Download HBIO—Evolution II Notes

HBIO—Evolution II Notes
I.
Measuring Change—Hardy Weinberg Equilibrium
a. Hardy-Weinberg Equilibrium—a mathematical formula that predicts that
genotype and gene frequencies will remain constant over time if:
i. Population is large
ii. All members reproduce freely
iii. No mutations
iv. No immigration / emigration
v. No Natural Selection
b. If any of the above conditions are violated, evolution will occur.
c. See Fishy Frequency Lab
II.
Speciation: a lineage-splitting event that produces two or more separate species that is
able to : 1. reproduce freely in nature 2. produce fertile offspring
a. Species—a group of individuals that can interbreed in nature (actually or
potentially) and produce fertile offspring.
b. Geographic Speciation (Power Point Example)
i. A physical barrier separates a population
ii. Each new population has a different environment and selects for different
traits.
iii. If populations get back together, may not be able to:
1. reproduce freely
2. produce fertile offspring
Adaptation: Organism or species becomes better suited to its environment
III.
Patterns of Evolution
a. Divergent Evolution / Adaptive Radiation—two or more species arise from a
common ancestor (result of varied environment)
ex./ Anole Lizard
Convergent Evolution—two distantly related species become more similar (result
of similar environments)
**Cannot become same species—too genetically different
ex./ groundhog and wombat, ostrich and emu
b. Co-evolution—two species adapt in response to eachother
ex./ hummingbirds and trumpet shaped flowers
IV.
Evidence of Evolution—See Stations
a. Fossils—evidence of earlier life in rock
i. Record is incomplete
ii. Oldest are simplest
iii. 90% of fossils are of organisms now extinct
iv. Use radioactive dating to help determine age of fossils
b. Comparative Anatomy
i. Homologous Structures—similar structure / different function
ii. Analogous Structures—similar function / different structure
iii. Vestigial Structures—no longer functions
c. Comparative Embryology—organisms that are more similar have more common
embryonic development
d. Comparative Biochemistry—DNA Comparisons and Molecular Evidence
i. DNA Comparisons—more genes and DNA sequences in common, the
more related organisms are
ii. Molecular Evidence—k