Unit 4: Sustainability of Ecosystems

Acid rain is any precipitation that has an unusually low pH. It can be rain, snow, fog, etc. But what is a low pH and why is this a problem?

Explore how walking on soil changes how water soaks into the ground and why that matters to gardeners and farmers.

Can carbon offsets help you reduce your environmental footprint, practice sustainable living and fight climate change?

This backgrounder explains what greenhouse gases are and how they contribute to climate change.

Biofuels like ethanol might help fight climate change. But they can contribute to food insecurity and greenhouse gases in ways that might surprise you.

What is the nitrogen cycle? How do human activities such as using fertilizer affect the nitrogen cycle? How can this cause greenhouse gases?

14 images of some plants such as carrots, cabbage and leeks whose roots, stems or leaves are used for food

Learn about two taxonomy systems that scientists use to classify the life around us.

Cloning makes it possible to bring extinct species back to life. But is that a good idea?

What's tasty, abundant and high in protein and vitamins? Bugs! Bugs feed about 2 billion people each day. They also hold promise for food security and sustainability.

10 images of some cold-blooded vertebrates such as snakes, lizards and alligators typically having dry, scaly skin

6 images of some seeds which are the fertilized part of a plant used for germinating new plants such as fennel, kiwis and pumpkins

The ocean is full of very small but very useful creatures called microbes. Without them, none of the sea plants or animals you’ve seen would exist!

A study on bird feeders and beak sizes shows how an everyday human activity can affect the evolution of another species.

9 images of plants in some large naturally occuring habitats called biomes such as tundra, grasslands and boreal forests