Hox Genes

Description:  Hox genes control the body plan of organisms with each hox gene coding for a specific body part. Hox gene mutations (e.g. a fruit fly with a leg in the place of an antenna) can lead to investigations on development. Similarities in hox genes across various animals can show phylogeny.

Web Resource: Hox genes - Wikipedia

What underlies the incredible diversity of life on Earth? How have complex life forms evolved? The journey from water to land, the return of land mammals to the sea, and the emergence of humans all suggest that creatures past and present are members of a single tree of life.

Megafauna Extinction: Humans or Climate?

Description:  North America (like Africa today) was once covered with large megafauna (animals weighing more than 100 pounds). This included giant mammoths, ground sloths, and beavers the size of a large bear. However most of these animals disappeared by 11,000 years ago. What was the cause of this extinction? Humans, climate, or a combination of the two? Phenomenon like this can be found around the World and can introduce the idea of human impacts on the environment.

Web Resource:  What Killed the Great Beasts of North America?

Complete video at: http://fora.tv/2010/05/18/Dr_Elizabeth_Hadly_Mammals_and_Climate_Change Stanford biologist Elizabeth Hadly recaps a debate among biologists over whether prehistoric megafauna like mammoths, giant sloths and saber-toothed cats became extinct due to overhunting by humans, or by a combination of hunting and a changing climate.