![Green walls in Harvard University](/sites/default/files/styles/resource_card_image_360x300_/public/2020-05/Green_wall_Harvard_University.jpg?itok=_ivWsw8S)
Green Walls
STEM Explained
Green walls use plant processes to improve air quality in buildings.
![Narwhals, polar bears and other common Arctic animals swim in the Arctic waters. Image © id-work, iStock](/sites/default/files/styles/resource_card_image_360x300_/public/2019-09/5755.jpg?itok=CVjIdhgO)
How are Arctic Animals in Canada Affected by Climate Change?
STEM Explained
Arctic animals have evolved to thrive in harsh arctic ecosystems, but the environmental footprint created by climate change is affecting their survival.
![bees on frame held by beekeeper](/sites/default/files/styles/resource_card_image_360x300_/public/2019-11/Bees_at_work.jpg?itok=eCBFpn4d)
How are the World's Bee Populations Doing?
STEM Explained
Bees are important for agriculture. But bee populations face threats. This resource looks at Colony Collapse Disorder, herbicides & pesticides, and more.
![Canaries were once used to signal dangers to miners. - Image © Vito Cangiulli, iStockPhoto.com](/sites/default/files/styles/resource_card_image_360x300_/public/2019-09/Canaries%20were%20once%20used%20to%20signal%20dangers%20to%20miners.jpg?itok=mc-wHhjT)
How Can Birds Help Monitor the Health of Ecosystems?
STEM Explained
Scientists can observe birds to get useful information about the health of, and changes in, an ecosystem.
![Goldfish Goldfish](/sites/default/files/styles/resource_card_image_360x300_/public/Gullfiskur.jpg?itok=L6czSzoc)
Fish: Freshwater
Picture Collections
4 images of some fish such as koi that live in freshwater river and lake environments and in freshwater aquariums and garden ponds
![Massive algal bloom](/sites/default/files/styles/resource_card_image_360x300_/public/2019-09/massive-algal-bloom.jpg?itok=pqgXB2yc)
Eutrophication: Why you should care about pond scum
STEM Explained
When fertilizers from agriculture get into lakes and rivers, big problems can result for aquatic ecosystems, food chains & webs!
![Grey Herons Building Nest Grey Herons Building Nest](/sites/default/files/styles/resource_card_image_360x300_/public/Ardea_cinerea_building_nest.jpg?itok=U8TThZvf)
Birds: Nest Construction
Picture Collections
images of some birds in the process of building their nests
![Nest With Eggs Nest With Eggs](/sites/default/files/styles/resource_card_image_360x300_/public/photo-1436731837106-3b37ef132fc2.jpg?itok=Gbo4Ab1n)
Birds: Nests
Picture Collections
10 images of some birds' nests showing various designs, structures and materials used for building them
![Eagle Eagle](/sites/default/files/styles/resource_card_image_360x300_/public/eagle2.jpg?itok=9md6UX31)
Birds: Raptors (Birds of Prey)
Picture Collections
5 images of predatory birds that hunt and feed on other animals such as eagles, the Great Horned Owl and vultures
![Blue Jay Blue Jay](/sites/default/files/styles/resource_card_image_360x300_/public/Bluejay.jpg?itok=txRE8CEw)
Birds: Songbirds
Picture Collections
10 images of some birds such as finches, chickadees and cardinals that produce sounds and calls in a musical way
![A beaver looks up from the water. Image © Jillian Cooper, iStockPhoto.com](/sites/default/files/styles/resource_card_image_360x300_/public/2019-09/A%20beaver%20looks%20up%20from%20the%20water.jpg?itok=KHUwOIhq)
Canadian Invaders!
STEM Explained
Beavers are a Canadian symbol. But in South America, they’re considered an invasive species.
![Green tree frog](/sites/default/files/styles/resource_card_image_360x300_/public/2019-12/Green_tree_frog.jpg?itok=Vf8kr8ir)
Amphibians
Picture Collections
12 images of some cold-blooded animals such as frogs and newts classified as amphibians that can live in the water or on land
![Chameleon blending in its surroundings](/sites/default/files/styles/resource_card_image_360x300_/public/2019-12/Cameleon_Tunisie_0.jpg?itok=KMn52lS1)
Animals: Adaptation
Picture Collections
11 images of some animals such as lizards and Arctic Hares whose appearance has adapted to provide protection in their environments
![Kitten Kitten](/sites/default/files/styles/resource_card_image_360x300_/public/11-cat.jpg?itok=IpDJVBPq)
Animals: Babies and Adults
Picture Collections
20 images of animal pairs such as polar bears, turtle, dogs and birds in their juvenile and adult stages of life
![Grizzly Bear Grizzly Bear](/sites/default/files/styles/resource_card_image_360x300_/public/Grizzly_Bear_Yellowstone.jpg?itok=kyKgyS-Q)
Animals: Hibernation
Picture Collections
10 images of some animals such as bears, bats, turtles and lemurs that spend the cold weather in a dormant state