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Unit 7: Evolution


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A trait that a species develops over time through natural selection.
Anatomy and Development
shows structures and embrios of organisms are similar and from commonm ancestor.
Behavior Isolation
Two species are capable of interbreeding but have different mating rituals
Species evolve with respect to one anther, predators and prey
Darwin's Finches
David Lack observes in wet season, sees nothing. Grants measure back sof finches regularly for many years and find are getting bigger
Darwin/HMS Beagle/Galapagos Islands.
Darwin came up with the now known correct theory of evolution and published it. He set out on Devember 27, 1831, to a journey around the world, where the galapogos infulenced him greatly.
Directional Selection
Phenotypes at one end are better, graph shifts
Get rid of less fit, but we are slowing evolution with medicine.
Disrubtive Selection
Phenotypes at both ends are better, graph splits in two
Compares DNA sequences to make phylogenic trees
Environment and Natural Selection
Natural Selection selects trait with respect to the organisms environment. Snowy=warm fur
Evidence for evolution
Fossil record, Geologic Distribution, Anatomy and Development, DNA
Change over time
Gets rid of less fit species, and forces surviving to adapt quickly to new environment
how well an organism can survive and reproduce.
Fossil Record
Physical record of history of life on earth
Galapagos Islands
They are all isolated, and have different environments, making them perfect for evolution.
Geographic Isolation
Seperated by geographic barriers
Geologic Distribution
Species living in similar environments evolve similarly, convergent evolution
Gradualism vs Puntuated Equilibrium
Gradual-evolves at same rate, puntu-evolves at same rate except during periods of rapid evol.
Homologous vs Vestigal Structures
Homo- structues with different mature forms but from same embrionic tissues, fore limbs in mammals. Vest- structures that have been reduced over time, tail bone
Horse Lab
The horse's environment was getting drier so it adapted to larger body, longer legs, more complex teeth, no toes.
Showed Industrial evolution: black moths dominated in polluted areas, white in nonpolluted
Lamarck, Hutton/Lyell, Malthus, Wallace
Came up with incorrect evol. ideas, geological processes take millions of years so Earth is old, if humans continue to grow there will not be enough rescources, sends Darwin his evol. essay
Miller and Ullrey
Used different machines simulating Earth's first events, starting with a mixture of gases and ending up with proteins.
Natural Selection
Says that individuals better suited to environment will survive and reproduce. Must be heritable variation, and competition for rescources.
Lived in cold environment, so developed warm feathers, oily waterproof coat, and huddling to stay warm.
Phenotypes vs Genotypes
Pheno is the physical trait, Geno is the genetic makeup of it
Must be able to reproduce together and produce fertile offspring
Stabilizing selection
PHenotypes at center of curve are better, graph narrows
Temporal isolation
Different species reproduce at different times of the year/dday
Where did Eukatyotes evolve from?
2 BYA, bacteria entered prokaryotes and turned into chloroplasts and mitochondria.

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