• the study of embryos in the early stages of development
• similarity in vertebrates suggests common ancestry
• every organism repeats its evolutionary development of own embryology

• proved possibility of Darwin's theory
• displayed different species and traits of one particular bird
• went against church's beliefs (controversy)

when a new population is started by only few individuals

ex - colonization of new world (started from a few europeans = huge population)

• preservation of bones
• document succession of life forms
• found in sedimentary rocks
• small insects in amber
• show decent of common ancestor

• look similar but have different functions
• common ancestor!!!
• ex- batwing + human hand
• DIVERGENT evolution

• look similar and have similar function

• NO COMMON ANCESTOR!
• CONVERGENT EVOLUTION

• creates variation
• changes DNA sequence

• struggle for existence
• each generation has just as much reproductive potential as previous
• more offspring are born than can live (famine, etc)

• aquire traits
• use it or lose it
• perfection with use
• if you want something bad enough, you can have it/grow it

1. Variation
2. more offspring are born than can survive (Malthus' idea)
3. struggle of existence (competition)
4. adaptations (characteristics beneficial to survival will become more common in population)
5. emergence of new species

• when heritable traits (help survive) become more popular in population over successive generations

parallel - similar ecological roles but not closely related

convergent - similar environments but not the same (analogous structures)

divergent - common ancestor but now different from different environments (homologous)

• proposed that world is older than church said it is (over 6000 years)
• earth is subject to slow but continuous cycles of erosion and uplift
• proposed uniformitarianism

1. fossil record
2. anatomical record
3. molecular record
4. artificial selection

1. mutation - changes DNA sequence

-creates variation

2.  gene flow - movement of alleles and individuals in and out of populations

ex- seed and pollen distribution, migration of animals

3.  non random mating - sexual selection

4.  genetic drift - chance events (founder effect + bottleneck)

• when a large population is reduced drastically by disaster
• ex - famine, loss of habitat, etc
• chance event
• narrows gene pool
• ex - cheetahs share small # of alleles and all are identical twins (1% diversity)

Cause? 2 bottlenecks= ice age + poaching/loss of habitat