Natural Selection-mechanism of change in populations.

o Individuals with certain variations are likely to survive, reproduce, and pass these variations to future generations

oOver time, offspring with certain variations make up most of the population and may look entirely different from their ancestors

^ƚƌƵĐƚƵƌĂůϭ͘ ĚĂƉƚĂƚŝŽŶƐ• D ŝŵŝĐƌLJ- ĞŶĂďůĞƐŽŶĞƐƉĞĐŝĞƐƚŽƌĞƐĞŵďůĞĂŶŽƚŚĞƌƐƉĞĐŝĞƐ

o ŚĂƌŵůĞƐƐƐƉĞĐŝĞƐŵĂLJƌĞƐĞŵďůĞĂŚĂƌŵĨƵůƐƉĞĐŝĞƐ ĂŶĚƚŚĞƌĞĨŽƌĞƉƌĞĚĂƚŽƌƐĂǀ ŽŝĚƚŚĞ ŵ͘

<ŝŶŐ̂ ŶĂŬdž͘ Ğ ůŽŽŬƐůŝŬĞ Ă ŽƌĂů̂ ŶĂŬĞ

• ĂŵŽƵĨůĂŐĞ - ĞŶĂďůĞƐƐƉĞĐŝĞƐ ƚŽďůĞŶĚǁ ŝƚŚƚŚĞŝƌƐƵƌƌŽƵŶĚŝŶŐ Ϯ͘ WŚLJƐŝŽůŽŐŝĐĂůĚĂƉƚĂƚŝŽŶƐ

• /ŶƐĞĐƚƐĂŶĚǁ ĞĞĚƐŵĂLJďĞĐŽŵĞƌĞƐŝƐƚĂŶƚƚŽĐŚĞŵŝĐĂůƐŝŶ ƉĞƐƚŝĐŝĚĞƐĂĨƚĞƌŵĂŶLJLJĞĂƌƐ

• ĂĐƚĞƌŝĂŚĂǀ ĞĚĞǀ ĞůŽƉĞĚĂƌĞƐŝƐƚĂŶĐĞƚŽƉĞŶŝĐŝůůŝŶ

ϯ͘ &ŽƐƐŝůƐ• ĂŶƐĞĞƚŚĞƐĞƋƵĞŶĐĞŽĨĞǀ ŽůƵƚŝŽŶ

4. Anatomy• Homologous structures- structural features with a

common evolutionary origino 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 functiono Wings on birds and insects

• Vestigial structures- body structure that has no function in a present day organism, but was probably useful to an ancestoro Ostrich have wings, but don’t flyo Humans have apendix, but don’t need it

Homologous Structures (above)

Analogous Structures (left)

5. Embryology• Embryos of various organisms are similar

6. Biochemistry• DNA and RNA in different species are similar