All living things (plants, animals, fungi and bacteria) are divided into categories called "species". Scientists continually discover and categorize new species, but every day day many more species on earth go extinct.

Having species of many kinds (biodiversity) is one of our Earth's greatest natural resources, but human activity is constantly reducing this variety by altering habitats, hunting, and/or introducing toxins and foreign species into the organism's ecosystem.

In this unit we will learn more about biodiversity and the adapations that organisms make to live in their environments.

Image: Biodiversity image from