evolution

who is james hutton

a geologist in the 1780s who believed that earth is very old and the surface has changed over time

what did Jean-Baptiste de Lamarck believe in his theory of aquired traits

organisms change over time through use and disuse of body parts and offspring inherited physical changes their parents acquired during their life

how was Lamarck’s theory proven wrong

Weismann’s experiement where he cut tails off mice for 20 generations and saw if it changed at all (it didn’t)

who is charles darwin

a naturalist on the HMS Beagle who discovered Darwinian evolution through finch beak differentiation on the galapagos

what did the HMS Beagle do

it was a scientific expedition exploring South America and circumnavigating the southern hemisphere from 1831-1836

what are the 4 concepts of darwinian evolution

1. all organisms produce far more offspring than can survive, but their numbers remain constant

2. all organisms must compete for limited food, mates, and living space

3. all organisms vary in their characteristics (no 2 are alike), which is heritable

4. survival of the fittest: organism that can survive the competition will live long enough to pass on their genes. Those who are unfit will die and their unfit genes with die with them

what is the evidence for evolution

1. artificial selection works, so should natural selection

2. fossil record shows changes in organisms over time

3. common ancestry can be seen in many groups of organisms

what is artificial selection

when man controls reproduction of organisms to obtain desired traits. Resulting offspring can be very different from their parents.

how do fossils form

they form in sedimentary rock when an organism is quickly covered by sediment: pressure and heat convert tissue into stone

types of fossils

mineralization, trace, resin, frozen

what are ways to date fossils and explain them

1. law of superposition: if undisturbed older rocks are towards the bottom, and younger rocks are above (relative dates)

2. index fossils: extinct life forms that lived for a known period of time

3. radioactive dating: gives actual age by measuring radioactive material

what is a half life

the time it take for an element to break in half, resulting in a daughter product

why are there gaps on the fossil record

fossils rarely form

what are homologous structures

parts of different organisms that have a similar structure and are evolutionary related

what are anologous structures

parts of different organism with similar function, but did not come from a common ancestor

what are vestigal structuers

nonfunctional structures that serve no role, but may have served a role in the past