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Plant Taxonomy

Variety of plant groups in Banff National Park, Alberta

Variety of plant groups in Banff National Park, Alberta (Don White, iStockphotos)

Variety of plant groups in Banff National Park, Alberta

Variety of plant groups in Banff National Park, Alberta (Don White, iStockphotos)

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Let's Talk Science
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Learn about the categories, or phylum, of the plant kingdom with examples from each.

Scientists like to classify living things in order to better understand their relationships. One way to do this is using Taxonomy. Taxonomy is the science of naming, describing and classifying organisms.

Modern taxonomy began in the mid-1700s. This is when Carl Linnaeus established a system to classify living organisms. He did this by giving every species a two-part Latin-based name. This is also known as a scientific name.

The Evolution of Classification Systems

Linnaeus classified organisms that could be seen with the naked eye into two large groups known as kingdoms. There were two kingdoms. The animal kingdom and the plant kingdom. This was based on whether or not they could move. Fungi were included with plants. Linnaeus further divided organisms by shared physical characteristics. His sub-groups included classes, orders, genera, and species. With the invention of the microscope around 1590, new organisms were discovered. This led to the need for more kingdoms.

The Five Kingdom system was first proposed in 1969. In this system, prokaryotes were put into a single kingdom called Monera. Most multicellular eukaryotes were either in the kingdom plantae (plants), animalia (animals) or fungi. Eukaryotes that did not fit elsewhere were put in the kingdom protista.

Not long after the five kingdom system was created, Carl Woese proposed a Six Kingdom system. He split the monera kingdom into two new kingdoms. These were archaea, which were ancient single-celled organisms and bacteria.

But Carl wasn’t finished thinking about classification. In 1990, he developed what is known as the Three Domain system. This system groups organisms mainly based on differences in the structure of the ribonucleic acid (RNA) found in their ribosomes. Within the three domains there are six kingdoms. These domains closely mirror the ones from 1977.

Shown is a colour illustration of the evolution of the kingdom classification system from the earliest in 1969 to 1977 and 1990.

Three different ways of organizing the kingdoms of life (©2022 Let’s Talk Science).

Image - Text Version

Shown is a colour illustration of the evolution of the kingdom classification system from the earliest in 1969 to 1977 and 1990. Colourful blocks shown from left to to right, display the names of each kingdom . 
1969: Five kingdom System
1977: Six Kingdom System
1990: Under three domains named bacteria, archaea and eukarya. Bacteria is further divided into the kingdom eubacteria, archae-bacteria is classified under the domain of archaea, and protist, plantae, fungi and animalia are all grouped under eukarya.

The Kingdom Plantae

All members of the plant kingdom share common features.

Plants:

  • are made of more than one cell. We call them multicellular
  • have cell walls
  • mainly cannot move
  • make their own food

The plant kingdom can be divided into groups based on plant structures. Plants with similar structures are grouped together. In the plant kingdom, these groups are called divisions.

Did you know?

The term “division” is used for plants and the term “phylum” is used for animals. Some scientists use the word “phylum” for both.

Plant Divisions 

Plants can first be divided into two groups. These are plants that make seeds and plants that do not make seeds. We call the subdivision of plants that make seeds phanerogams. We call the subdivision that does not make seeds cryptogams.

Shown is a colour flowchart of divisions within the plant kingdom with examples from each.

Plant divisions with examples (©2022 Let’s Talk Science).

Image - Text Version

Shown is a colour flowchart of divisions within the plant kingdom with examples from each.

Starting from the top, green blocks with text have connecting lines that branch out to other related blocks below. Under each block is an colour image example of each plant division.

At top centre is Kingdom Plantae branching into two categories of has no seeds or has seeds. If no seeds, then the plants can then be further classified into has no true roots, stems or leaves, has some root and leaf-like structures or has roots, stems and leaves. If has seeds, the plant can be classified into the categories of has flowers or has no flowers.

The example of a plant with no true roots, stems or leaves is algae. A green plant with wavy looking narrow leaves is shown. Below the image is the word "Algae" and the group name "Chlorophyta".

The example of a plant that has some root and leaf-like structures or has roots are mosses and liverworts. A small green plant resembling tiny pipe cleaners is shown. Below the image are the words "Mosses and Liverworts" and the group name "Bryophyta".

The example of a plant that has roots, stems and leaves are ferns and horsetails. A green plant with feather-like leaves is shown. Below the image are the words "Ferns and Horsetails" and the group name "Pteridophyta". 

There are two examples of plants that has no flowers or gymnosperms. The first are conifers, they have needle -like leaves. Below the image is the word "Conifers" and the group name "Pinophyta". The second example are ginkos and cycads, and they have wide green leaves. Below the image are the words "Ginkos and Cycads" and the group names "Ginkgophyta" and "Cycadphyta".

The example of a plant that has flowers are angiosperms. A plant with green, jagged narrow leaves and yellow round flowers is shown. Below the image is the word "Angiosperms" and the group name "Magnoliophyta".

From there, the subdivisions can be further divided. A common way to group cryptograms is by structure. Some cryptograms have roots, stems and leaves. Others only have some of these parts. Others still do not have any of these parts. Let’s look at these divisions in more depth.

The division chlorophyta contains algae. Land plants evolved from a group of green algae, as early as 850 million years ago. Scientists have found a fossil algae that lived around one billion years ago!

Algae are a diverse group of plants. They range from tiny single-celled organisms to gigantic seaweed.

Did you know?

There are seven types of algae. These are green algae, euglenoids, golden-brown algae, fire algae, red algae, yellow-green algae and brown algae.

Shown are two colour photos. On the left is a photo of single-celled algae and on the right is a photo of a kelp forest.

Right: Single-celled chlorella algae (Source: Sinhyu via iStockphoto); left: Kelp forest (Source: Shur_ca via iStockphoto).

Image - Text Version

Shown are two colour photos. On the left is a photo of single-celled algae and on the right is a photo of a kelp forest.
In the algae photo, each algae is a small, pale green translucent circle. A large group of algae is located in the upper left and bottom centre of the image. Individual algae are scattered around the rest of the image. The background is a pale grey colour.
In the kelp photo, a tall column of pale green leaves originates at the bottom centre of the image and continues up to the top of the image. The surrounding water is light blue in colour and appears a little cloudy. On the right a few larger fish can be seen in the foreground and a few smaller ones in the back. Narrow columns of sea kelp stand vertically in the background.

Misconception Alert

Seaweeds do not have roots, stems are leaves. But they do have parts that act in similar ways. They have holdfasts that act like roots, stipes that act like stems and blades that act like leaves. Some seaweeds also have air-filled bladders that help them float.

Algae are primarily aquatic. They live both in freshwater as well as marine habitats. But did you know they can also be found on land? Algae can have a symbiotic relationship with fungi. This results in a composite organism we call a lichen. A lichen is actually two organisms that work together like a single organism.

Algae and Climate Change 

Earth’s climate is warming. One of the results of this is a warming of the water on Earth. Algae grows better in warm water. In some places, blue-green algae grow so quickly that they lead to a problem called algal blooms. Algae blooms can cause clear water to become cloudy as well as form scum on the surface of the water. Algal blooms can make people sick when they swim in that water.

But fast-growing algae is not necessarily a bad thing. As algae grows, it removes carbon dioxide from the atmosphere through photosynthesis. Research has shown that, on average, one kilogram of algae uses 1.87 kilograms of CO2 each day. This means that one acre (4046.86 m2) of algae uses approximately 2.7 tons of CO2 per day. For comparison, one acre of a 25-year-old maple-beech-birch forest only uses 2.18 kilograms of CO2 per day.

Did you know?

We can also make plant-based fuel, or biofuel, using algae.

Why the world needs more algae, not less. (2021) by DW Planet (8:24 min.)

Chlorophyta – Freshwater and Marine Algae

The division chlorophyta contains algae. Land plants evolved from a group of green algae, as early as 850 million years ago. Scientists have found a fossil algae that lived around one billion years ago!

Algae are a diverse group of plants. They range from tiny single-celled organisms to gigantic seaweed.

Did you know?

There are seven types of algae. These are green algae, euglenoids, golden-brown algae, fire algae, red algae, yellow-green algae and brown algae.

Shown are two colour photos. On the left is a photo of single-celled algae and on the right is a photo of a kelp forest.

Right: Single-celled chlorella algae (Source: Sinhyu via iStockphoto); left: Kelp forest (Source: Shur_ca via iStockphoto).

Image - Text Version

Shown are two colour photos. On the left is a photo of single-celled algae and on the right is a photo of a kelp forest.
In the algae photo, each algae is a small, pale green translucent circle. A large group of algae is located in the upper left and bottom centre of the image. Individual algae are scattered around the rest of the image. The background is a pale grey colour.
In the kelp photo, a tall column of pale green leaves originates at the bottom centre of the image and continues up to the top of the image. The surrounding water is light blue in colour and appears a little cloudy. On the right a few larger fish can be seen in the foreground and a few smaller ones in the back. Narrow columns of sea kelp stand vertically in the background.

Misconception Alert

Seaweeds do not have roots, stems are leaves. But they do have parts that act in similar ways. They have holdfasts that act like roots, stipes that act like stems and blades that act like leaves. Some seaweeds also have air-filled bladders that help them float.

Algae are primarily aquatic. They live both in freshwater as well as marine habitats. But did you know they can also be found on land? Algae can have a symbiotic relationship with fungi. This results in a composite organism we call a lichen. A lichen is actually two organisms that work together like a single organism.

Algae and Climate Change 

Earth’s climate is warming. One of the results of this is a warming of the water on Earth. Algae grows better in warm water. In some places, blue-green algae grow so quickly that they lead to a problem called algal blooms. Algae blooms can cause clear water to become cloudy as well as form scum on the surface of the water. Algal blooms can make people sick when they swim in that water.

But fast-growing algae is not necessarily a bad thing. As algae grows, it removes carbon dioxide from the atmosphere through photosynthesis. Research has shown that, on average, one kilogram of algae uses 1.87 kilograms of CO2 each day. This means that one acre (4046.86 m2) of algae uses approximately 2.7 tons of CO2 per day. For comparison, one acre of a 25-year-old maple-beech-birch forest only uses 2.18 kilograms of CO2 per day.

Did you know?

We can also make plant-based fuel, or biofuel, using algae.

Why the world needs more algae, not less. (2021) by DW Planet (8:24 min.)

These are the oldest land plants. The first mosses appeared around 450 million years ago. Mosses live on land and prefer damp and shady areas. They often grow in dense, soft clumps. Mosses are one of the first types of plants to become established on rocky ground. They can break down rock, which helps to form soil.

Shown is a colour photo of an assortment of mosses against a white background.

Assortment of mosses (Source: Antagain via iStockphoto).

Image - Text Version

Shown is a colour photo of an assortment of mosses against a white background. 

A large mat of pale green, frilly plants dominate the centre of the image.  Some of the mosses have longer branching parts while others are shorter with denser branches. Each type of moss is a different shade of pale green.

Mosses are more advanced than algae, but less advanced from other plants because they do not have a vascular system. This means that they do not have specialized tissue to transport water throughout the plant. Instead, mosses get their water, nutrients and minerals by a process called osmosis. During osmosis, water moves from areas with a lot of water to areas with less water. Since Bryophyta cannot easily move water and nutrients around a large plant, mosses grow low to the ground. Most mosses are only a few centimetres high). Mosses also do not have roots. Instead, mosses have rhizoids. These are root-like threads that help anchor the plant to the ground. Unlike roots, rhizoids do not take in water or nutrients.

Did you know?

Mosses are able to absorb 20 to 30 times their weight in water!

Liverworts grow in similar habitats to mosses. The main part of the plant is flat and often branched. Some plants resemble the human liver, hence the name.

Mosses and Climate Change 

Scientists have learned that mosses are very sensitive to changes in temperature and humidity. Warmer conditions due to climate change will allow some mosses to do better and other mosses to do worse. Fewer mosses in places like the tundra and boreal forest will decrease their ability to store carbon. Although they only cover about 3% of the Earth’s land surface, peat mosses store about a third of the Earth’s soil carbon.

Bryophyta – Mosses and Liverworts

These are the oldest land plants. The first mosses appeared around 450 million years ago. Mosses live on land and prefer damp and shady areas. They often grow in dense, soft clumps. Mosses are one of the first types of plants to become established on rocky ground. They can break down rock, which helps to form soil.

Shown is a colour photo of an assortment of mosses against a white background.

Assortment of mosses (Source: Antagain via iStockphoto).

Image - Text Version

Shown is a colour photo of an assortment of mosses against a white background. 

A large mat of pale green, frilly plants dominate the centre of the image.  Some of the mosses have longer branching parts while others are shorter with denser branches. Each type of moss is a different shade of pale green.

Mosses are more advanced than algae, but less advanced from other plants because they do not have a vascular system. This means that they do not have specialized tissue to transport water throughout the plant. Instead, mosses get their water, nutrients and minerals by a process called osmosis. During osmosis, water moves from areas with a lot of water to areas with less water. Since Bryophyta cannot easily move water and nutrients around a large plant, mosses grow low to the ground. Most mosses are only a few centimetres high). Mosses also do not have roots. Instead, mosses have rhizoids. These are root-like threads that help anchor the plant to the ground. Unlike roots, rhizoids do not take in water or nutrients.

Did you know?

Mosses are able to absorb 20 to 30 times their weight in water!

Liverworts grow in similar habitats to mosses. The main part of the plant is flat and often branched. Some plants resemble the human liver, hence the name.

Mosses and Climate Change 

Scientists have learned that mosses are very sensitive to changes in temperature and humidity. Warmer conditions due to climate change will allow some mosses to do better and other mosses to do worse. Fewer mosses in places like the tundra and boreal forest will decrease their ability to store carbon. Although they only cover about 3% of the Earth’s land surface, peat mosses store about a third of the Earth’s soil carbon.

Yet more advanced are pteridophytes. This group includes ferns and horsetails. Unlike mosses, ferns do have a vascular system to transport water and nutrients. The vascular system includes tissues such as xylem and phloem. Ferns have roots that absorb water and nutrients from the soil. These get transported to the stems and leaves via the xylem and phloem. Ferns are also known for their fiddleheads. These are the curled-up leaves of young ferns. Ferns grow in a variety of habitats. These include swamps and damp forests.

Shown are photographs of a fiddlehead on the left, fern leaves in the centre image and horsetail stalks on the right.

Left: Fiddlehead (Source: Alkalyne via iStockphoto); Centre: Fern leaves (Source: hepatus via iStockphoto); Right: Water horsetails (Source: aga7ta via iStockphoto).

Image - Text Version

Shown are photographs of a fiddlehead on the left, fern leaves in the centre image and horsetail stalks on the right.

A fiddlehead is a new leaf on a fern. The foreground contains a rosette of arching leaves resembling the neck of a violin, with a smooth, green stem that has a deep, u-shaped groove on the inside of the stem. Its tiny leaves are tightly curled. Mature fern leaves can be seen in the dark background.

The fern plant has a number of pale green leaves with serrated edges. Each leaf branches into many smaller branches. Other shaded leaves are visible in the background.

A horsetail is a plant with few to no leaves. Several joined pale green stems are visible. There are small tufts of narrow leaves at the base of each section of stem. The light green stems are ribbed and each has a conical top. The background is light green to yellow and appears out of focus.

Horsetails are easily recognized by their jointed stems. If you find a horsetail, you can easily pull the stem apart at the joints. Branches can sometimes be seen radiating out from the joints. Like ferns, horsetails can be found in damp forests and along the banks of rivers.

Did you know?

Horsetails are also known as “scouring rushes” because they were used to scrub with. They were also sometimes used as toothbrushes!

Ferns and Climate Change 

Ferns make the perfect early warning system for climate change. They are very sensitive to changes in temperature and rainfall. For example, if the tip of your fern turns brown, the air in your house is likely too dry.

Scientists who research fossil plants have used fossil ferns to reconstruct past climates. For example, around 55 million years ago, the Earth was very hot. The Arctic Ocean was more of an enclosed hot lake, similar to today's Dead Sea. It became the perfect habitat for a small floating fern called Azolla.

Shown is a colour photograph of Azolla ferns on the surface of a rice field.

Azolla fern on the surface of wet rice field (Source: Retdar [CC BY-SA 4.0] via Wikimedia Commons)

Image - Text Version

Shown is a colour photograph of Azolla ferns on the surface of a rice field.

The dark blue water is almost completely covered by fern leaves. Each leaf has a triangular shape with many tiny leaflets. The leaves are a darker green towards their centres and a lighter green towards their edges.

 

The high levels of nitrogen and carbon dioxide (CO2) enabled the Azolla to thrive. They flourished for about a million years. During that time, the Azolla took CO2 out of the air and cooled the climate. So much so that it became too cold for them!

Scientists are researching different ways to use Azolla to help cool our planet. This includes growing them as a farm crop. They are nutritious and mild tasting. They do not take up land and can grow anywhere in the world.

Pteridophyta – Ferns and Horsetails

Yet more advanced are pteridophytes. This group includes ferns and horsetails. Unlike mosses, ferns do have a vascular system to transport water and nutrients. The vascular system includes tissues such as xylem and phloem. Ferns have roots that absorb water and nutrients from the soil. These get transported to the stems and leaves via the xylem and phloem. Ferns are also known for their fiddleheads. These are the curled-up leaves of young ferns. Ferns grow in a variety of habitats. These include swamps and damp forests.

Shown are photographs of a fiddlehead on the left, fern leaves in the centre image and horsetail stalks on the right.

Left: Fiddlehead (Source: Alkalyne via iStockphoto); Centre: Fern leaves (Source: hepatus via iStockphoto); Right: Water horsetails (Source: aga7ta via iStockphoto).

Image - Text Version

Shown are photographs of a fiddlehead on the left, fern leaves in the centre image and horsetail stalks on the right.

A fiddlehead is a new leaf on a fern. The foreground contains a rosette of arching leaves resembling the neck of a violin, with a smooth, green stem that has a deep, u-shaped groove on the inside of the stem. Its tiny leaves are tightly curled. Mature fern leaves can be seen in the dark background.

The fern plant has a number of pale green leaves with serrated edges. Each leaf branches into many smaller branches. Other shaded leaves are visible in the background.

A horsetail is a plant with few to no leaves. Several joined pale green stems are visible. There are small tufts of narrow leaves at the base of each section of stem. The light green stems are ribbed and each has a conical top. The background is light green to yellow and appears out of focus.

Horsetails are easily recognized by their jointed stems. If you find a horsetail, you can easily pull the stem apart at the joints. Branches can sometimes be seen radiating out from the joints. Like ferns, horsetails can be found in damp forests and along the banks of rivers.

Did you know?

Horsetails are also known as “scouring rushes” because they were used to scrub with. They were also sometimes used as toothbrushes!

Ferns and Climate Change 

Ferns make the perfect early warning system for climate change. They are very sensitive to changes in temperature and rainfall. For example, if the tip of your fern turns brown, the air in your house is likely too dry.

Scientists who research fossil plants have used fossil ferns to reconstruct past climates. For example, around 55 million years ago, the Earth was very hot. The Arctic Ocean was more of an enclosed hot lake, similar to today's Dead Sea. It became the perfect habitat for a small floating fern called Azolla.

Shown is a colour photograph of Azolla ferns on the surface of a rice field.

Azolla fern on the surface of wet rice field (Source: Retdar [CC BY-SA 4.0] via Wikimedia Commons)

Image - Text Version

Shown is a colour photograph of Azolla ferns on the surface of a rice field.

The dark blue water is almost completely covered by fern leaves. Each leaf has a triangular shape with many tiny leaflets. The leaves are a darker green towards their centres and a lighter green towards their edges.

 

The high levels of nitrogen and carbon dioxide (CO2) enabled the Azolla to thrive. They flourished for about a million years. During that time, the Azolla took CO2 out of the air and cooled the climate. So much so that it became too cold for them!

Scientists are researching different ways to use Azolla to help cool our planet. This includes growing them as a farm crop. They are nutritious and mild tasting. They do not take up land and can grow anywhere in the world.

Members of this division are gymnosperms (gym-no-sperms). Gymnosperms are the first group of vascular plants to produce seeds. Gymnosperms have seeds that do not have an outer covering, hence their name. The word gymnosperm comes from the Greek words gymno, meaning “naked,” and sperm, meaning “seed.”

People often call members of this division conifers. Conifers include pines, cedars, junipers, spruces, firs and many others.

Shown is a colour photograph of examples of conifer branches and cones.

Examples of conifer branches including pine, spruce and cedar (Source: LiliGraphie via iStockphoto).

Image - Text Version

Shown is a colour photograph of examples of conifer branches and cones.
There are six examples in a row across the top of the image and seven examples in a row at the bottom. The branches are in various shades of medium to dark green. The branches all have narrow green needle-shaped leaves or different lengths. Some branches also have cones. The cones are oval with overlapping paler brown scales.

Conifers can be recognized by their needles and cones. The needles of conifers are specialized leaves. They have a thick waxy covering that helps cut down on water loss. The cones are where the seeds are located.

Most conifers are evergreen. This means that they do not drop their needles in the winter. Instead, they replace them gradually over their lifetime. By staying green, the needles can make food for the plant year round. An exception to the rule are Tamaracks. The needles of these conifers turn bright yellow in autumn and then fall off.

Conifers are mainly found in the northern hemisphere. They are one of the most common plants in taiga regions. They thrive in areas where summers are short and winters are long, due to their ability to retain water during the winter. 

Did you know?

Some of the tallest trees are conifers. Some, like Sequoias, can grow more than 90 metres tall!

Shown is a colour photograph of a very large tree in a forest.

Picea sitchensis, a Sitka spruce on Vancouver Island (Source: Tim Gage [CC BY-SA 2.0] via Wikimedia Commons).

Image - Text Version

Shown is a colour photograph of a very large tree in a forest.
The trunk of a very large tree dominates the images. The trunk is so large that only the bottom part is visible. The trunk rises up out of rich brown soil. Green moss covers the left side of its expansive knotted trunk. A smaller trunk branches off from the right side of the main trunk. Younger trees and pale green shrubs are visible in the background. Huddled together near the trunk are two people. One is wearing dark blue clothing and the other is wearing a red vest and dark jeans.

Conifers and Climate Change

Conifers have already become victims of climate change. Large numbers of conifers have been lost due to droughts and wildfires. As the Earth gets warmer, Coniferous forests could be pushed to the tipping point. This is the point at which a species cannot recover from stress and becomes extinct. Anywhere from 16 to 54 percent of coniferous forests could be gone by the end of this century.

In planting trees today, there is a bias towards planting conifers, especially for timber production. Conifers are fast growing trees that have many uses, including for wood and for paper. There are pros and cons for growing so many conifers. On one hand, conifers can capture carbon as they grow. This is a good thing. On the other hand, conifers have darker coloured leaves than deciduous trees. This causes them to absorb heat from the Sun and warm the surrounding area. This is not a good thing. As we consider what trees to plant, we must consider all of these factors.

Pinophyta – Conifers

Members of this division are gymnosperms (gym-no-sperms). Gymnosperms are the first group of vascular plants to produce seeds. Gymnosperms have seeds that do not have an outer covering, hence their name. The word gymnosperm comes from the Greek words gymno, meaning “naked,” and sperm, meaning “seed.”

People often call members of this division conifers. Conifers include pines, cedars, junipers, spruces, firs and many others.

Shown is a colour photograph of examples of conifer branches and cones.

Examples of conifer branches including pine, spruce and cedar (Source: LiliGraphie via iStockphoto).

Image - Text Version

Shown is a colour photograph of examples of conifer branches and cones.
There are six examples in a row across the top of the image and seven examples in a row at the bottom. The branches are in various shades of medium to dark green. The branches all have narrow green needle-shaped leaves or different lengths. Some branches also have cones. The cones are oval with overlapping paler brown scales.

Conifers can be recognized by their needles and cones. The needles of conifers are specialized leaves. They have a thick waxy covering that helps cut down on water loss. The cones are where the seeds are located.

Most conifers are evergreen. This means that they do not drop their needles in the winter. Instead, they replace them gradually over their lifetime. By staying green, the needles can make food for the plant year round. An exception to the rule are Tamaracks. The needles of these conifers turn bright yellow in autumn and then fall off.

Conifers are mainly found in the northern hemisphere. They are one of the most common plants in taiga regions. They thrive in areas where summers are short and winters are long, due to their ability to retain water during the winter. 

Did you know?

Some of the tallest trees are conifers. Some, like Sequoias, can grow more than 90 metres tall!

Shown is a colour photograph of a very large tree in a forest.

Picea sitchensis, a Sitka spruce on Vancouver Island (Source: Tim Gage [CC BY-SA 2.0] via Wikimedia Commons).

Image - Text Version

Shown is a colour photograph of a very large tree in a forest.
The trunk of a very large tree dominates the images. The trunk is so large that only the bottom part is visible. The trunk rises up out of rich brown soil. Green moss covers the left side of its expansive knotted trunk. A smaller trunk branches off from the right side of the main trunk. Younger trees and pale green shrubs are visible in the background. Huddled together near the trunk are two people. One is wearing dark blue clothing and the other is wearing a red vest and dark jeans.

Conifers and Climate Change

Conifers have already become victims of climate change. Large numbers of conifers have been lost due to droughts and wildfires. As the Earth gets warmer, Coniferous forests could be pushed to the tipping point. This is the point at which a species cannot recover from stress and becomes extinct. Anywhere from 16 to 54 percent of coniferous forests could be gone by the end of this century.

In planting trees today, there is a bias towards planting conifers, especially for timber production. Conifers are fast growing trees that have many uses, including for wood and for paper. There are pros and cons for growing so many conifers. On one hand, conifers can capture carbon as they grow. This is a good thing. On the other hand, conifers have darker coloured leaves than deciduous trees. This causes them to absorb heat from the Sun and warm the surrounding area. This is not a good thing. As we consider what trees to plant, we must consider all of these factors.

Most members of these groups are now extinct. There is only one ginkgophyta species left on Earth. This is Ginkgo biloba, commonly called the ginkgo tree. Ginkgo trees are easily recognized by their fan-shaped leaves. Ginkgo’s also have very memorable fruit. The outer fleshy layer smells like vomit when it starts to rot! If you can get past that, the inner part is edible.

Did you know?

Fossil ginkgo leaves have been found dating back to the Permian period (270 million years ago).

Shown are two colour photos. On the left are ginkgo leaves. On the right is a cycad growing on a green grassy field.

Left: Ginkgo leaves (Source: v_apl via iStockphoto); Right: Cycad (Source: ViniSouza128 via iStockphoto).

Image -  Text Version

Shown are two colour photos. On the left are ginkgo leaves. On the right is a cycad growing on a green grassy field.

In the ginkgo leaves photo, the leaves are two-lobed, fan-shaped, light green in colour. The leaves are flat with irregular notches on the outer edge. The leaf veins grow nearly parallel into the main stem. The background is green and white in colour.

In the cycad photo, this tree has a cylindrical, short trunk with layered fringes. The evergreen leaves grow directly from the top of the trunk, creating a crown of foliage. The leaves are often quite large relative to the size of the trunk and tend to fan-out upwards. In the background is a red-clay pathway and beyond that, some tall grass, shrubs and the bottom portion of a tree trunk can be seen.

Cycads are also a very old group of seed plants. Fossil evidence shows that these plants existed in the Mesozoic Era (251.9 million to 66 million years ago). The cones of cycads are usually found at the top of the tree where the branches develop. Sago palms (Cycas revoluta), a type of cycad, are often grown as ornamental plants. Because they are so popular, some species are becoming nearly extinct in the wild.

Ginkgos and Climate Change

Ginkgos are very tough trees. It was one of the first trees to regrow after the bombing of Hiroshima at the end of World War II. Gingkos have also been shown to have high resistance to stresses like diseases, insects and air pollution.

It also doesn’t seem to mind warm temperatures. Scientists have found that during warm periods, the growing season of ginkgos gets longer. Finally, since they have been around for so long, scientists can use fossils of leaves to understand how climate has changed by counting their stomata.

Ginkgophyta and Cycadophyta – Ginkgos and Cycads

Most members of these groups are now extinct. There is only one ginkgophyta species left on Earth. This is Ginkgo biloba, commonly called the ginkgo tree. Ginkgo trees are easily recognized by their fan-shaped leaves. Ginkgo’s also have very memorable fruit. The outer fleshy layer smells like vomit when it starts to rot! If you can get past that, the inner part is edible.

Did you know?

Fossil ginkgo leaves have been found dating back to the Permian period (270 million years ago).

Shown are two colour photos. On the left are ginkgo leaves. On the right is a cycad growing on a green grassy field.

Left: Ginkgo leaves (Source: v_apl via iStockphoto); Right: Cycad (Source: ViniSouza128 via iStockphoto).

Image -  Text Version

Shown are two colour photos. On the left are ginkgo leaves. On the right is a cycad growing on a green grassy field.

In the ginkgo leaves photo, the leaves are two-lobed, fan-shaped, light green in colour. The leaves are flat with irregular notches on the outer edge. The leaf veins grow nearly parallel into the main stem. The background is green and white in colour.

In the cycad photo, this tree has a cylindrical, short trunk with layered fringes. The evergreen leaves grow directly from the top of the trunk, creating a crown of foliage. The leaves are often quite large relative to the size of the trunk and tend to fan-out upwards. In the background is a red-clay pathway and beyond that, some tall grass, shrubs and the bottom portion of a tree trunk can be seen.

Cycads are also a very old group of seed plants. Fossil evidence shows that these plants existed in the Mesozoic Era (251.9 million to 66 million years ago). The cones of cycads are usually found at the top of the tree where the branches develop. Sago palms (Cycas revoluta), a type of cycad, are often grown as ornamental plants. Because they are so popular, some species are becoming nearly extinct in the wild.

Ginkgos and Climate Change

Ginkgos are very tough trees. It was one of the first trees to regrow after the bombing of Hiroshima at the end of World War II. Gingkos have also been shown to have high resistance to stresses like diseases, insects and air pollution.

It also doesn’t seem to mind warm temperatures. Scientists have found that during warm periods, the growing season of ginkgos gets longer. Finally, since they have been around for so long, scientists can use fossils of leaves to understand how climate has changed by counting their stomata.

Flowering plants are the most diverse and successful group of plants on Earth. In fact, flowering plants make up approximately 90 percent of the Kingdom Plantae. Flowering plants can be found just about everywhere on Earth. You can find them from the driest deserts to the wettest rainforest and everywhere in between! Flowering plants include many familiar types such as grasses, roses, cacti and most deciduous trees.

The term for plants with flowers is angiosperm. Angiosperms are seed-producing plants with flowers and fruits that enclose the seeds. Angiosperms are part of the phylum magnoliophyta.

Shown is a colour photo of a Yellow Trout Lily flowering plant.

A Yellow Trout Lily (Erythronium americanum) is an example of a flowering plant (Source: Katja Schulz [CC BY 2.0] via Wikimedia Commons).

Image - Text Version

Shown is a colour photo of a Yellow Trout Lily flowering plant. In sharp focus and in the foreground, are brown-spotted green leaves arising from the ground. Brownish green shoots appear between the leaves and lemon-yellow flowers with six petals hang downwards. Orange or reddish brown anthers emerge from the flowers. Dry, brown leaves appear at lower left of the image. Out of focus in the background are various shades of grey, green and brown.

Flowering Plants and Climate Change

Flowers can adapt to changing temperatures by increasing or decreasing the amount of Ultraviolet (UV) pigment in their petals. Flowers' UV pigments form patterns that are invisible to the human eye. These patterns attract pollinators and act as a kind of sunscreen for plants. UV radiation can be harmful to humans, and it can also affect the ability of a plant to reproduce.

Many pollinators are drawn to flowers with a "bull's-eye" pattern. These are flowers that have petals which reflect UV on their tips and absorb UV at their bases. Flowers that increase their UV overall could lose that contrast. So although the flower may keep its pollen from being damaged, it may lose its pollinators.

Shown are 15 colour photographs of flowers that appear yellow under visible light, and bright blue under ultraviolet light.

Images of flowers as they appear in visible light (yellow, green and black images) and ultraviolet light (blue and black images) (Source: Matthew Gronquist, Alexander Bezzerides, Athula Atttygalle, Jerrold Mainwald, Maria Eisner, and Thomas Eisner (2001), Attractive and defensive functions of the ultraviolet pigments of a flower (Hypericum calycinum). PNAS 98 (24): 13745-13750. Copyright (2001) National Academy of Sciences, U.S.A Used with permission.).

Image - Text Version

Shown are 15 colour photographs of flowers that appear yellow under visible light, and bright blue under ultraviolet light.

Under visible light, the flowers are bright yellow on black backgrounds. In ultraviolet light, different parts of the flowers are more visible.

For example, in the first photograph, the flower appears entirely one shade of yellow. In the second photograph, the flower's outside petals appear bright blue, while a large part of the centre is very dark blue.

Each photograph is labelled in the top left or bottom left corner, from A - O.

 

 

Magnoliophyta – Flowering Plants

Flowering plants are the most diverse and successful group of plants on Earth. In fact, flowering plants make up approximately 90 percent of the Kingdom Plantae. Flowering plants can be found just about everywhere on Earth. You can find them from the driest deserts to the wettest rainforest and everywhere in between! Flowering plants include many familiar types such as grasses, roses, cacti and most deciduous trees.

The term for plants with flowers is angiosperm. Angiosperms are seed-producing plants with flowers and fruits that enclose the seeds. Angiosperms are part of the phylum magnoliophyta.

Shown is a colour photo of a Yellow Trout Lily flowering plant.

A Yellow Trout Lily (Erythronium americanum) is an example of a flowering plant (Source: Katja Schulz [CC BY 2.0] via Wikimedia Commons).

Image - Text Version

Shown is a colour photo of a Yellow Trout Lily flowering plant. In sharp focus and in the foreground, are brown-spotted green leaves arising from the ground. Brownish green shoots appear between the leaves and lemon-yellow flowers with six petals hang downwards. Orange or reddish brown anthers emerge from the flowers. Dry, brown leaves appear at lower left of the image. Out of focus in the background are various shades of grey, green and brown.

Flowering Plants and Climate Change

Flowers can adapt to changing temperatures by increasing or decreasing the amount of Ultraviolet (UV) pigment in their petals. Flowers' UV pigments form patterns that are invisible to the human eye. These patterns attract pollinators and act as a kind of sunscreen for plants. UV radiation can be harmful to humans, and it can also affect the ability of a plant to reproduce.

Many pollinators are drawn to flowers with a "bull's-eye" pattern. These are flowers that have petals which reflect UV on their tips and absorb UV at their bases. Flowers that increase their UV overall could lose that contrast. So although the flower may keep its pollen from being damaged, it may lose its pollinators.

Shown are 15 colour photographs of flowers that appear yellow under visible light, and bright blue under ultraviolet light.

Images of flowers as they appear in visible light (yellow, green and black images) and ultraviolet light (blue and black images) (Source: Matthew Gronquist, Alexander Bezzerides, Athula Atttygalle, Jerrold Mainwald, Maria Eisner, and Thomas Eisner (2001), Attractive and defensive functions of the ultraviolet pigments of a flower (Hypericum calycinum). PNAS 98 (24): 13745-13750. Copyright (2001) National Academy of Sciences, U.S.A Used with permission.).

Image - Text Version

Shown are 15 colour photographs of flowers that appear yellow under visible light, and bright blue under ultraviolet light.

Under visible light, the flowers are bright yellow on black backgrounds. In ultraviolet light, different parts of the flowers are more visible.

For example, in the first photograph, the flower appears entirely one shade of yellow. In the second photograph, the flower's outside petals appear bright blue, while a large part of the centre is very dark blue.

Each photograph is labelled in the top left or bottom left corner, from A - O.

 

 

The division chlorophyta contains algae. Land plants evolved from a group of green algae, as early as 850 million years ago. Scientists have found a fossil algae that lived around one billion years ago!

Algae are a diverse group of plants. They range from tiny single-celled organisms to gigantic seaweed.

Did you know?

There are seven types of algae. These are green algae, euglenoids, golden-brown algae, fire algae, red algae, yellow-green algae and brown algae.

Shown are two colour photos. On the left is a photo of single-celled algae and on the right is a photo of a kelp forest.

Right: Single-celled chlorella algae (Source: Sinhyu via iStockphoto); left: Kelp forest (Source: Shur_ca via iStockphoto).

Image - Text Version

Shown are two colour photos. On the left is a photo of single-celled algae and on the right is a photo of a kelp forest.
In the algae photo, each algae is a small, pale green translucent circle. A large group of algae is located in the upper left and bottom centre of the image. Individual algae are scattered around the rest of the image. The background is a pale grey colour.
In the kelp photo, a tall column of pale green leaves originates at the bottom centre of the image and continues up to the top of the image. The surrounding water is light blue in colour and appears a little cloudy. On the right a few larger fish can be seen in the foreground and a few smaller ones in the back. Narrow columns of sea kelp stand vertically in the background.

Misconception Alert

Seaweeds do not have roots, stems are leaves. But they do have parts that act in similar ways. They have holdfasts that act like roots, stipes that act like stems and blades that act like leaves. Some seaweeds also have air-filled bladders that help them float.

Algae are primarily aquatic. They live both in freshwater as well as marine habitats. But did you know they can also be found on land? Algae can have a symbiotic relationship with fungi. This results in a composite organism we call a lichen. A lichen is actually two organisms that work together like a single organism.

Algae and Climate Change 

Earth’s climate is warming. One of the results of this is a warming of the water on Earth. Algae grows better in warm water. In some places, blue-green algae grow so quickly that they lead to a problem called algal blooms. Algae blooms can cause clear water to become cloudy as well as form scum on the surface of the water. Algal blooms can make people sick when they swim in that water.

But fast-growing algae is not necessarily a bad thing. As algae grows, it removes carbon dioxide from the atmosphere through photosynthesis. Research has shown that, on average, one kilogram of algae uses 1.87 kilograms of CO2 each day. This means that one acre (4046.86 m2) of algae uses approximately 2.7 tons of CO2 per day. For comparison, one acre of a 25-year-old maple-beech-birch forest only uses 2.18 kilograms of CO2 per day.

Did you know?

We can also make plant-based fuel, or biofuel, using algae.

Why the world needs more algae, not less. (2021) by DW Planet (8:24 min.)

Chlorophyta – Freshwater and Marine Algae

The division chlorophyta contains algae. Land plants evolved from a group of green algae, as early as 850 million years ago. Scientists have found a fossil algae that lived around one billion years ago!

Algae are a diverse group of plants. They range from tiny single-celled organisms to gigantic seaweed.

Did you know?

There are seven types of algae. These are green algae, euglenoids, golden-brown algae, fire algae, red algae, yellow-green algae and brown algae.

Shown are two colour photos. On the left is a photo of single-celled algae and on the right is a photo of a kelp forest.

Right: Single-celled chlorella algae (Source: Sinhyu via iStockphoto); left: Kelp forest (Source: Shur_ca via iStockphoto).

Image - Text Version

Shown are two colour photos. On the left is a photo of single-celled algae and on the right is a photo of a kelp forest.
In the algae photo, each algae is a small, pale green translucent circle. A large group of algae is located in the upper left and bottom centre of the image. Individual algae are scattered around the rest of the image. The background is a pale grey colour.
In the kelp photo, a tall column of pale green leaves originates at the bottom centre of the image and continues up to the top of the image. The surrounding water is light blue in colour and appears a little cloudy. On the right a few larger fish can be seen in the foreground and a few smaller ones in the back. Narrow columns of sea kelp stand vertically in the background.

Misconception Alert

Seaweeds do not have roots, stems are leaves. But they do have parts that act in similar ways. They have holdfasts that act like roots, stipes that act like stems and blades that act like leaves. Some seaweeds also have air-filled bladders that help them float.

Algae are primarily aquatic. They live both in freshwater as well as marine habitats. But did you know they can also be found on land? Algae can have a symbiotic relationship with fungi. This results in a composite organism we call a lichen. A lichen is actually two organisms that work together like a single organism.

Algae and Climate Change 

Earth’s climate is warming. One of the results of this is a warming of the water on Earth. Algae grows better in warm water. In some places, blue-green algae grow so quickly that they lead to a problem called algal blooms. Algae blooms can cause clear water to become cloudy as well as form scum on the surface of the water. Algal blooms can make people sick when they swim in that water.

But fast-growing algae is not necessarily a bad thing. As algae grows, it removes carbon dioxide from the atmosphere through photosynthesis. Research has shown that, on average, one kilogram of algae uses 1.87 kilograms of CO2 each day. This means that one acre (4046.86 m2) of algae uses approximately 2.7 tons of CO2 per day. For comparison, one acre of a 25-year-old maple-beech-birch forest only uses 2.18 kilograms of CO2 per day.

Did you know?

We can also make plant-based fuel, or biofuel, using algae.

Why the world needs more algae, not less. (2021) by DW Planet (8:24 min.)

These are the oldest land plants. The first mosses appeared around 450 million years ago. Mosses live on land and prefer damp and shady areas. They often grow in dense, soft clumps. Mosses are one of the first types of plants to become established on rocky ground. They can break down rock, which helps to form soil.

Shown is a colour photo of an assortment of mosses against a white background.

Assortment of mosses (Source: Antagain via iStockphoto).

Image - Text Version

Shown is a colour photo of an assortment of mosses against a white background. 

A large mat of pale green, frilly plants dominate the centre of the image.  Some of the mosses have longer branching parts while others are shorter with denser branches. Each type of moss is a different shade of pale green.

Mosses are more advanced than algae, but less advanced from other plants because they do not have a vascular system. This means that they do not have specialized tissue to transport water throughout the plant. Instead, mosses get their water, nutrients and minerals by a process called osmosis. During osmosis, water moves from areas with a lot of water to areas with less water. Since Bryophyta cannot easily move water and nutrients around a large plant, mosses grow low to the ground. Most mosses are only a few centimetres high). Mosses also do not have roots. Instead, mosses have rhizoids. These are root-like threads that help anchor the plant to the ground. Unlike roots, rhizoids do not take in water or nutrients.

Did you know?

Mosses are able to absorb 20 to 30 times their weight in water!

Liverworts grow in similar habitats to mosses. The main part of the plant is flat and often branched. Some plants resemble the human liver, hence the name.

Mosses and Climate Change 

Scientists have learned that mosses are very sensitive to changes in temperature and humidity. Warmer conditions due to climate change will allow some mosses to do better and other mosses to do worse. Fewer mosses in places like the tundra and boreal forest will decrease their ability to store carbon. Although they only cover about 3% of the Earth’s land surface, peat mosses store about a third of the Earth’s soil carbon.

Bryophyta – Mosses and Liverworts

These are the oldest land plants. The first mosses appeared around 450 million years ago. Mosses live on land and prefer damp and shady areas. They often grow in dense, soft clumps. Mosses are one of the first types of plants to become established on rocky ground. They can break down rock, which helps to form soil.

Shown is a colour photo of an assortment of mosses against a white background.

Assortment of mosses (Source: Antagain via iStockphoto).

Image - Text Version

Shown is a colour photo of an assortment of mosses against a white background. 

A large mat of pale green, frilly plants dominate the centre of the image.  Some of the mosses have longer branching parts while others are shorter with denser branches. Each type of moss is a different shade of pale green.

Mosses are more advanced than algae, but less advanced from other plants because they do not have a vascular system. This means that they do not have specialized tissue to transport water throughout the plant. Instead, mosses get their water, nutrients and minerals by a process called osmosis. During osmosis, water moves from areas with a lot of water to areas with less water. Since Bryophyta cannot easily move water and nutrients around a large plant, mosses grow low to the ground. Most mosses are only a few centimetres high). Mosses also do not have roots. Instead, mosses have rhizoids. These are root-like threads that help anchor the plant to the ground. Unlike roots, rhizoids do not take in water or nutrients.

Did you know?

Mosses are able to absorb 20 to 30 times their weight in water!

Liverworts grow in similar habitats to mosses. The main part of the plant is flat and often branched. Some plants resemble the human liver, hence the name.

Mosses and Climate Change 

Scientists have learned that mosses are very sensitive to changes in temperature and humidity. Warmer conditions due to climate change will allow some mosses to do better and other mosses to do worse. Fewer mosses in places like the tundra and boreal forest will decrease their ability to store carbon. Although they only cover about 3% of the Earth’s land surface, peat mosses store about a third of the Earth’s soil carbon.

Yet more advanced are pteridophytes. This group includes ferns and horsetails. Unlike mosses, ferns do have a vascular system to transport water and nutrients. The vascular system includes tissues such as xylem and phloem. Ferns have roots that absorb water and nutrients from the soil. These get transported to the stems and leaves via the xylem and phloem. Ferns are also known for their fiddleheads. These are the curled-up leaves of young ferns. Ferns grow in a variety of habitats. These include swamps and damp forests.

Shown are photographs of a fiddlehead on the left, fern leaves in the centre image and horsetail stalks on the right.

Left: Fiddlehead (Source: Alkalyne via iStockphoto); Centre: Fern leaves (Source: hepatus via iStockphoto); Right: Water horsetails (Source: aga7ta via iStockphoto).

Image - Text Version

Shown are photographs of a fiddlehead on the left, fern leaves in the centre image and horsetail stalks on the right.

A fiddlehead is a new leaf on a fern. The foreground contains a rosette of arching leaves resembling the neck of a violin, with a smooth, green stem that has a deep, u-shaped groove on the inside of the stem. Its tiny leaves are tightly curled. Mature fern leaves can be seen in the dark background.

The fern plant has a number of pale green leaves with serrated edges. Each leaf branches into many smaller branches. Other shaded leaves are visible in the background.

A horsetail is a plant with few to no leaves. Several joined pale green stems are visible. There are small tufts of narrow leaves at the base of each section of stem. The light green stems are ribbed and each has a conical top. The background is light green to yellow and appears out of focus.

Horsetails are easily recognized by their jointed stems. If you find a horsetail, you can easily pull the stem apart at the joints. Branches can sometimes be seen radiating out from the joints. Like ferns, horsetails can be found in damp forests and along the banks of rivers.

Did you know?

Horsetails are also known as “scouring rushes” because they were used to scrub with. They were also sometimes used as toothbrushes!

Ferns and Climate Change 

Ferns make the perfect early warning system for climate change. They are very sensitive to changes in temperature and rainfall. For example, if the tip of your fern turns brown, the air in your house is likely too dry.

Scientists who research fossil plants have used fossil ferns to reconstruct past climates. For example, around 55 million years ago, the Earth was very hot. The Arctic Ocean was more of an enclosed hot lake, similar to today's Dead Sea. It became the perfect habitat for a small floating fern called Azolla.

Shown is a colour photograph of Azolla ferns on the surface of a rice field.

Azolla fern on the surface of wet rice field (Source: Retdar [CC BY-SA 4.0] via Wikimedia Commons)

Image - Text Version

Shown is a colour photograph of Azolla ferns on the surface of a rice field.

The dark blue water is almost completely covered by fern leaves. Each leaf has a triangular shape with many tiny leaflets. The leaves are a darker green towards their centres and a lighter green towards their edges.

 

The high levels of nitrogen and carbon dioxide (CO2) enabled the Azolla to thrive. They flourished for about a million years. During that time, the Azolla took CO2 out of the air and cooled the climate. So much so that it became too cold for them!

Scientists are researching different ways to use Azolla to help cool our planet. This includes growing them as a farm crop. They are nutritious and mild tasting. They do not take up land and can grow anywhere in the world.

Pteridophyta – Ferns and Horsetails

Yet more advanced are pteridophytes. This group includes ferns and horsetails. Unlike mosses, ferns do have a vascular system to transport water and nutrients. The vascular system includes tissues such as xylem and phloem. Ferns have roots that absorb water and nutrients from the soil. These get transported to the stems and leaves via the xylem and phloem. Ferns are also known for their fiddleheads. These are the curled-up leaves of young ferns. Ferns grow in a variety of habitats. These include swamps and damp forests.

Shown are photographs of a fiddlehead on the left, fern leaves in the centre image and horsetail stalks on the right.

Left: Fiddlehead (Source: Alkalyne via iStockphoto); Centre: Fern leaves (Source: hepatus via iStockphoto); Right: Water horsetails (Source: aga7ta via iStockphoto).

Image - Text Version

Shown are photographs of a fiddlehead on the left, fern leaves in the centre image and horsetail stalks on the right.

A fiddlehead is a new leaf on a fern. The foreground contains a rosette of arching leaves resembling the neck of a violin, with a smooth, green stem that has a deep, u-shaped groove on the inside of the stem. Its tiny leaves are tightly curled. Mature fern leaves can be seen in the dark background.

The fern plant has a number of pale green leaves with serrated edges. Each leaf branches into many smaller branches. Other shaded leaves are visible in the background.

A horsetail is a plant with few to no leaves. Several joined pale green stems are visible. There are small tufts of narrow leaves at the base of each section of stem. The light green stems are ribbed and each has a conical top. The background is light green to yellow and appears out of focus.

Horsetails are easily recognized by their jointed stems. If you find a horsetail, you can easily pull the stem apart at the joints. Branches can sometimes be seen radiating out from the joints. Like ferns, horsetails can be found in damp forests and along the banks of rivers.

Did you know?

Horsetails are also known as “scouring rushes” because they were used to scrub with. They were also sometimes used as toothbrushes!

Ferns and Climate Change 

Ferns make the perfect early warning system for climate change. They are very sensitive to changes in temperature and rainfall. For example, if the tip of your fern turns brown, the air in your house is likely too dry.

Scientists who research fossil plants have used fossil ferns to reconstruct past climates. For example, around 55 million years ago, the Earth was very hot. The Arctic Ocean was more of an enclosed hot lake, similar to today's Dead Sea. It became the perfect habitat for a small floating fern called Azolla.

Shown is a colour photograph of Azolla ferns on the surface of a rice field.

Azolla fern on the surface of wet rice field (Source: Retdar [CC BY-SA 4.0] via Wikimedia Commons)

Image - Text Version

Shown is a colour photograph of Azolla ferns on the surface of a rice field.

The dark blue water is almost completely covered by fern leaves. Each leaf has a triangular shape with many tiny leaflets. The leaves are a darker green towards their centres and a lighter green towards their edges.

 

The high levels of nitrogen and carbon dioxide (CO2) enabled the Azolla to thrive. They flourished for about a million years. During that time, the Azolla took CO2 out of the air and cooled the climate. So much so that it became too cold for them!

Scientists are researching different ways to use Azolla to help cool our planet. This includes growing them as a farm crop. They are nutritious and mild tasting. They do not take up land and can grow anywhere in the world.

Members of this division are gymnosperms (gym-no-sperms). Gymnosperms are the first group of vascular plants to produce seeds. Gymnosperms have seeds that do not have an outer covering, hence their name. The word gymnosperm comes from the Greek words gymno, meaning “naked,” and sperm, meaning “seed.”

People often call members of this division conifers. Conifers include pines, cedars, junipers, spruces, firs and many others.

Shown is a colour photograph of examples of conifer branches and cones.

Examples of conifer branches including pine, spruce and cedar (Source: LiliGraphie via iStockphoto).

Image - Text Version

Shown is a colour photograph of examples of conifer branches and cones.
There are six examples in a row across the top of the image and seven examples in a row at the bottom. The branches are in various shades of medium to dark green. The branches all have narrow green needle-shaped leaves or different lengths. Some branches also have cones. The cones are oval with overlapping paler brown scales.

Conifers can be recognized by their needles and cones. The needles of conifers are specialized leaves. They have a thick waxy covering that helps cut down on water loss. The cones are where the seeds are located.

Most conifers are evergreen. This means that they do not drop their needles in the winter. Instead, they replace them gradually over their lifetime. By staying green, the needles can make food for the plant year round. An exception to the rule are Tamaracks. The needles of these conifers turn bright yellow in autumn and then fall off.

Conifers are mainly found in the northern hemisphere. They are one of the most common plants in taiga regions. They thrive in areas where summers are short and winters are long, due to their ability to retain water during the winter. 

Did you know?

Some of the tallest trees are conifers. Some, like Sequoias, can grow more than 90 metres tall!

Shown is a colour photograph of a very large tree in a forest.

Picea sitchensis, a Sitka spruce on Vancouver Island (Source: Tim Gage [CC BY-SA 2.0] via Wikimedia Commons).

Image - Text Version

Shown is a colour photograph of a very large tree in a forest.
The trunk of a very large tree dominates the images. The trunk is so large that only the bottom part is visible. The trunk rises up out of rich brown soil. Green moss covers the left side of its expansive knotted trunk. A smaller trunk branches off from the right side of the main trunk. Younger trees and pale green shrubs are visible in the background. Huddled together near the trunk are two people. One is wearing dark blue clothing and the other is wearing a red vest and dark jeans.

Conifers and Climate Change

Conifers have already become victims of climate change. Large numbers of conifers have been lost due to droughts and wildfires. As the Earth gets warmer, Coniferous forests could be pushed to the tipping point. This is the point at which a species cannot recover from stress and becomes extinct. Anywhere from 16 to 54 percent of coniferous forests could be gone by the end of this century.

In planting trees today, there is a bias towards planting conifers, especially for timber production. Conifers are fast growing trees that have many uses, including for wood and for paper. There are pros and cons for growing so many conifers. On one hand, conifers can capture carbon as they grow. This is a good thing. On the other hand, conifers have darker coloured leaves than deciduous trees. This causes them to absorb heat from the Sun and warm the surrounding area. This is not a good thing. As we consider what trees to plant, we must consider all of these factors.

Pinophyta – Conifers

Members of this division are gymnosperms (gym-no-sperms). Gymnosperms are the first group of vascular plants to produce seeds. Gymnosperms have seeds that do not have an outer covering, hence their name. The word gymnosperm comes from the Greek words gymno, meaning “naked,” and sperm, meaning “seed.”

People often call members of this division conifers. Conifers include pines, cedars, junipers, spruces, firs and many others.

Shown is a colour photograph of examples of conifer branches and cones.

Examples of conifer branches including pine, spruce and cedar (Source: LiliGraphie via iStockphoto).

Image - Text Version

Shown is a colour photograph of examples of conifer branches and cones.
There are six examples in a row across the top of the image and seven examples in a row at the bottom. The branches are in various shades of medium to dark green. The branches all have narrow green needle-shaped leaves or different lengths. Some branches also have cones. The cones are oval with overlapping paler brown scales.

Conifers can be recognized by their needles and cones. The needles of conifers are specialized leaves. They have a thick waxy covering that helps cut down on water loss. The cones are where the seeds are located.

Most conifers are evergreen. This means that they do not drop their needles in the winter. Instead, they replace them gradually over their lifetime. By staying green, the needles can make food for the plant year round. An exception to the rule are Tamaracks. The needles of these conifers turn bright yellow in autumn and then fall off.

Conifers are mainly found in the northern hemisphere. They are one of the most common plants in taiga regions. They thrive in areas where summers are short and winters are long, due to their ability to retain water during the winter. 

Did you know?

Some of the tallest trees are conifers. Some, like Sequoias, can grow more than 90 metres tall!

Shown is a colour photograph of a very large tree in a forest.

Picea sitchensis, a Sitka spruce on Vancouver Island (Source: Tim Gage [CC BY-SA 2.0] via Wikimedia Commons).

Image - Text Version

Shown is a colour photograph of a very large tree in a forest.
The trunk of a very large tree dominates the images. The trunk is so large that only the bottom part is visible. The trunk rises up out of rich brown soil. Green moss covers the left side of its expansive knotted trunk. A smaller trunk branches off from the right side of the main trunk. Younger trees and pale green shrubs are visible in the background. Huddled together near the trunk are two people. One is wearing dark blue clothing and the other is wearing a red vest and dark jeans.

Conifers and Climate Change

Conifers have already become victims of climate change. Large numbers of conifers have been lost due to droughts and wildfires. As the Earth gets warmer, Coniferous forests could be pushed to the tipping point. This is the point at which a species cannot recover from stress and becomes extinct. Anywhere from 16 to 54 percent of coniferous forests could be gone by the end of this century.

In planting trees today, there is a bias towards planting conifers, especially for timber production. Conifers are fast growing trees that have many uses, including for wood and for paper. There are pros and cons for growing so many conifers. On one hand, conifers can capture carbon as they grow. This is a good thing. On the other hand, conifers have darker coloured leaves than deciduous trees. This causes them to absorb heat from the Sun and warm the surrounding area. This is not a good thing. As we consider what trees to plant, we must consider all of these factors.

Most members of these groups are now extinct. There is only one ginkgophyta species left on Earth. This is Ginkgo biloba, commonly called the ginkgo tree. Ginkgo trees are easily recognized by their fan-shaped leaves. Ginkgo’s also have very memorable fruit. The outer fleshy layer smells like vomit when it starts to rot! If you can get past that, the inner part is edible.

Did you know?

Fossil ginkgo leaves have been found dating back to the Permian period (270 million years ago).

Shown are two colour photos. On the left are ginkgo leaves. On the right is a cycad growing on a green grassy field.

Left: Ginkgo leaves (Source: v_apl via iStockphoto); Right: Cycad (Source: ViniSouza128 via iStockphoto).

Image -  Text Version

Shown are two colour photos. On the left are ginkgo leaves. On the right is a cycad growing on a green grassy field.

In the ginkgo leaves photo, the leaves are two-lobed, fan-shaped, light green in colour. The leaves are flat with irregular notches on the outer edge. The leaf veins grow nearly parallel into the main stem. The background is green and white in colour.

In the cycad photo, this tree has a cylindrical, short trunk with layered fringes. The evergreen leaves grow directly from the top of the trunk, creating a crown of foliage. The leaves are often quite large relative to the size of the trunk and tend to fan-out upwards. In the background is a red-clay pathway and beyond that, some tall grass, shrubs and the bottom portion of a tree trunk can be seen.

Cycads are also a very old group of seed plants. Fossil evidence shows that these plants existed in the Mesozoic Era (251.9 million to 66 million years ago). The cones of cycads are usually found at the top of the tree where the branches develop. Sago palms (Cycas revoluta), a type of cycad, are often grown as ornamental plants. Because they are so popular, some species are becoming nearly extinct in the wild.

Ginkgos and Climate Change

Ginkgos are very tough trees. It was one of the first trees to regrow after the bombing of Hiroshima at the end of World War II. Gingkos have also been shown to have high resistance to stresses like diseases, insects and air pollution.

It also doesn’t seem to mind warm temperatures. Scientists have found that during warm periods, the growing season of ginkgos gets longer. Finally, since they have been around for so long, scientists can use fossils of leaves to understand how climate has changed by counting their stomata.

Ginkgophyta and Cycadophyta – Ginkgos and Cycads

Most members of these groups are now extinct. There is only one ginkgophyta species left on Earth. This is Ginkgo biloba, commonly called the ginkgo tree. Ginkgo trees are easily recognized by their fan-shaped leaves. Ginkgo’s also have very memorable fruit. The outer fleshy layer smells like vomit when it starts to rot! If you can get past that, the inner part is edible.

Did you know?

Fossil ginkgo leaves have been found dating back to the Permian period (270 million years ago).

Shown are two colour photos. On the left are ginkgo leaves. On the right is a cycad growing on a green grassy field.

Left: Ginkgo leaves (Source: v_apl via iStockphoto); Right: Cycad (Source: ViniSouza128 via iStockphoto).

Image -  Text Version

Shown are two colour photos. On the left are ginkgo leaves. On the right is a cycad growing on a green grassy field.

In the ginkgo leaves photo, the leaves are two-lobed, fan-shaped, light green in colour. The leaves are flat with irregular notches on the outer edge. The leaf veins grow nearly parallel into the main stem. The background is green and white in colour.

In the cycad photo, this tree has a cylindrical, short trunk with layered fringes. The evergreen leaves grow directly from the top of the trunk, creating a crown of foliage. The leaves are often quite large relative to the size of the trunk and tend to fan-out upwards. In the background is a red-clay pathway and beyond that, some tall grass, shrubs and the bottom portion of a tree trunk can be seen.

Cycads are also a very old group of seed plants. Fossil evidence shows that these plants existed in the Mesozoic Era (251.9 million to 66 million years ago). The cones of cycads are usually found at the top of the tree where the branches develop. Sago palms (Cycas revoluta), a type of cycad, are often grown as ornamental plants. Because they are so popular, some species are becoming nearly extinct in the wild.

Ginkgos and Climate Change

Ginkgos are very tough trees. It was one of the first trees to regrow after the bombing of Hiroshima at the end of World War II. Gingkos have also been shown to have high resistance to stresses like diseases, insects and air pollution.

It also doesn’t seem to mind warm temperatures. Scientists have found that during warm periods, the growing season of ginkgos gets longer. Finally, since they have been around for so long, scientists can use fossils of leaves to understand how climate has changed by counting their stomata.

Flowering plants are the most diverse and successful group of plants on Earth. In fact, flowering plants make up approximately 90 percent of the Kingdom Plantae. Flowering plants can be found just about everywhere on Earth. You can find them from the driest deserts to the wettest rainforest and everywhere in between! Flowering plants include many familiar types such as grasses, roses, cacti and most deciduous trees.

The term for plants with flowers is angiosperm. Angiosperms are seed-producing plants with flowers and fruits that enclose the seeds. Angiosperms are part of the phylum magnoliophyta.

Shown is a colour photo of a Yellow Trout Lily flowering plant.

A Yellow Trout Lily (Erythronium americanum) is an example of a flowering plant (Source: Katja Schulz [CC BY 2.0] via Wikimedia Commons).

Image - Text Version

Shown is a colour photo of a Yellow Trout Lily flowering plant. In sharp focus and in the foreground, are brown-spotted green leaves arising from the ground. Brownish green shoots appear between the leaves and lemon-yellow flowers with six petals hang downwards. Orange or reddish brown anthers emerge from the flowers. Dry, brown leaves appear at lower left of the image. Out of focus in the background are various shades of grey, green and brown.

Flowering Plants and Climate Change

Flowers can adapt to changing temperatures by increasing or decreasing the amount of Ultraviolet (UV) pigment in their petals. Flowers' UV pigments form patterns that are invisible to the human eye. These patterns attract pollinators and act as a kind of sunscreen for plants. UV radiation can be harmful to humans, and it can also affect the ability of a plant to reproduce.

Many pollinators are drawn to flowers with a "bull's-eye" pattern. These are flowers that have petals which reflect UV on their tips and absorb UV at their bases. Flowers that increase their UV overall could lose that contrast. So although the flower may keep its pollen from being damaged, it may lose its pollinators.

Shown are 15 colour photographs of flowers that appear yellow under visible light, and bright blue under ultraviolet light.

Images of flowers as they appear in visible light (yellow, green and black images) and ultraviolet light (blue and black images) (Source: Matthew Gronquist, Alexander Bezzerides, Athula Atttygalle, Jerrold Mainwald, Maria Eisner, and Thomas Eisner (2001), Attractive and defensive functions of the ultraviolet pigments of a flower (Hypericum calycinum). PNAS 98 (24): 13745-13750. Copyright (2001) National Academy of Sciences, U.S.A Used with permission.).

Image - Text Version

Shown are 15 colour photographs of flowers that appear yellow under visible light, and bright blue under ultraviolet light.

Under visible light, the flowers are bright yellow on black backgrounds. In ultraviolet light, different parts of the flowers are more visible.

For example, in the first photograph, the flower appears entirely one shade of yellow. In the second photograph, the flower's outside petals appear bright blue, while a large part of the centre is very dark blue.

Each photograph is labelled in the top left or bottom left corner, from A - O.

 

 

Magnoliophyta – Flowering Plants

Flowering plants are the most diverse and successful group of plants on Earth. In fact, flowering plants make up approximately 90 percent of the Kingdom Plantae. Flowering plants can be found just about everywhere on Earth. You can find them from the driest deserts to the wettest rainforest and everywhere in between! Flowering plants include many familiar types such as grasses, roses, cacti and most deciduous trees.

The term for plants with flowers is angiosperm. Angiosperms are seed-producing plants with flowers and fruits that enclose the seeds. Angiosperms are part of the phylum magnoliophyta.

Shown is a colour photo of a Yellow Trout Lily flowering plant.

A Yellow Trout Lily (Erythronium americanum) is an example of a flowering plant (Source: Katja Schulz [CC BY 2.0] via Wikimedia Commons).

Image - Text Version

Shown is a colour photo of a Yellow Trout Lily flowering plant. In sharp focus and in the foreground, are brown-spotted green leaves arising from the ground. Brownish green shoots appear between the leaves and lemon-yellow flowers with six petals hang downwards. Orange or reddish brown anthers emerge from the flowers. Dry, brown leaves appear at lower left of the image. Out of focus in the background are various shades of grey, green and brown.

Flowering Plants and Climate Change

Flowers can adapt to changing temperatures by increasing or decreasing the amount of Ultraviolet (UV) pigment in their petals. Flowers' UV pigments form patterns that are invisible to the human eye. These patterns attract pollinators and act as a kind of sunscreen for plants. UV radiation can be harmful to humans, and it can also affect the ability of a plant to reproduce.

Many pollinators are drawn to flowers with a "bull's-eye" pattern. These are flowers that have petals which reflect UV on their tips and absorb UV at their bases. Flowers that increase their UV overall could lose that contrast. So although the flower may keep its pollen from being damaged, it may lose its pollinators.

Shown are 15 colour photographs of flowers that appear yellow under visible light, and bright blue under ultraviolet light.

Images of flowers as they appear in visible light (yellow, green and black images) and ultraviolet light (blue and black images) (Source: Matthew Gronquist, Alexander Bezzerides, Athula Atttygalle, Jerrold Mainwald, Maria Eisner, and Thomas Eisner (2001), Attractive and defensive functions of the ultraviolet pigments of a flower (Hypericum calycinum). PNAS 98 (24): 13745-13750. Copyright (2001) National Academy of Sciences, U.S.A Used with permission.).

Image - Text Version

Shown are 15 colour photographs of flowers that appear yellow under visible light, and bright blue under ultraviolet light.

Under visible light, the flowers are bright yellow on black backgrounds. In ultraviolet light, different parts of the flowers are more visible.

For example, in the first photograph, the flower appears entirely one shade of yellow. In the second photograph, the flower's outside petals appear bright blue, while a large part of the centre is very dark blue.

Each photograph is labelled in the top left or bottom left corner, from A - O.

 

 

Learn More

Who was Linnaeus?
Stories and videos about the life and work of Carl Linnaeus from The Linnean Society.

Taxonomy: Life's Filing System (2012)
Video (12:15 min.) from Crash Course explaining the history and importance of taxonomy.

What's in a Lichen? How Scientists Got It Wrong for 150 Years
Video (4:12 min.) from National Geographic. For 150 years, scientists believed lichen were defined by a symbiotic relationship between a fungus and algae. Meet the team of researchers who question this belief.

Algae Biofuel: Can Pond Scum Power The Planet?
A STEM in Context article by Let’s Talk Science. Learn about the potential of algae as a material for making biofuel.

What Gingko Leaves Can Tell Us About Climate Change
This video (3:56) from PBS/NOVA discusses how the gingko tree can be used as way to track the progress of atmospheric CO2 levels over history. 

References

AnnBurg, V. (2021, Sep. 11) How saving Ginkgo biloba could save humankind: Paleobotanical Future. Society of Ethnobiology.

Bailey, R. (2109, Nov. 28) Three domain system - how biological life is classified. ThoughtCo.

Biology Online (2022, Aug. 27) Dictionary - Chlorophyta definition.

Coghlan, J. (n.d.) What to plant? Broadleaf vs. Conifer. The Carbon Community.

Hicks, L. (2020, Sep. 28) Flower colours are changing in response to climate change. Science.

Huizen, J. (2014, Jul. 15) Can the Fern That Cooled the Planet Do It Again? Scientific American.

Panawala, L. (2017, Oct. 3) Difference between phylum and division. Research Gate.

Rader's Biology4Kids.com. (n.d.). Taxonomy.

Reuters, T. (2016, Feb. 4) Conifer forest expansion blamed for boosting global warming. CB. Science.

Streich, A. M., Todd, K. A., (2014) Classification and naming of plants. Extension 

Toochi EC. (2018) Carbon sequestration: how much can forestry sequester CO2?. Forest Res Eng Int J. 2(3): 148–150. 

Waghmare, P. (2021, Aug. 3) Plant kingdom: Types, characteristics, examples of phylum. Testbook.