What do scientists compare to determin the evolutionary relationships among organisms?
Body structure, development before birth, and DNA sequences.
How did Darwin come to understand that evolution had occurred on the Galapagos Islands?
Body structures of living species.
What is an organism's body structure?
It is thebasic body plan, such as how its bones are arranged.
What are homologous structures?
Similar structures that related species have inherited from a common ancestor.
What trait does the chicken, rat, and turtle all share when in the fetus?
A tail and tiny gill slits in their throats.
What have scientists begun doing when comparing different species?
Scientists have begun to compare the genes of different species to determine who closely related two species are.
What else have scientists use this DNA technique on?
Fossils of bones, teeth, plants, and insects trapped in amber.
What is a branching tree?
A branching tree is a diagram that shows how scientists think different groups of organisms are related.