3.  Natural Selection-mechanism of change in populations. o Individuals with certain variations are likely to survive, reproduce, and pass these variations to future generations o Over time, offspring with certain variations make up most of the population and may look entirely different from their ancestors

5. 4. Anatomy Homologous structures- structural features with a common evolutionary origin o Forelimbs of crocodiles, whales, and birds are similar Analogous structures- body parts of organisms that do not have a common origin, but are similar in function o Wings on birds and insects Vestigial structures- body structure that has no function in a present day organism, but was probably useful to an ancestor o Ostrich have wings, but don’t fly o Humans have apendix, but don’t need it

6. Homologous Structures (above) Analogous Structures (left)

7. 5. Embryology Embryos of various organisms are similar 6. Biochemistry DNA and RNA in different species are similar