PBS Evolution, Episode 2
One of the most difficult concepts to grasp in learning about evolution is the notion of speciation -- the emergence of new species from an ancestor. This episode gives some compelling examples and evidence of speciation, particularly revolving around how animals first emerged onto land, and in the case of whales, returned back to the sea.
Key Concepts: Natural selection, adaptations, divergent speciation, mammal evolution, transitional forms, fossils, vestigial structures, Cambrian explosion, embryology, DNA, mutations, bipedalism, quadrupedalism.
Answer Key: Available at the biology instructor resources subscription page.