Tonight's Reading/Studying

The final exam of the semester looms in the distance, so PLEASE study!  You have all of your notes/handouts.  Here are a few categories to study:

Chapter 13:
1)  Evidence for evolution:  fossil record, biogeography, comparative anatomy (including homologous structures and vestigial structures),  comparing embryonic development, and molecular biology (similarities in amino acid and DNA sequences)
2)  Sources of genetic variation:  mutation, crossing over and independent assortment (during meiosis), random fertilization
3)  How do you know if a population is evolving?  Hardy-Weinberg--that's how.  Look over the equation, remembering what each variable represents!
4)  The five conditions that must be met in order for a population to be in Hardy-Weinberg equilibrium (i.e. NOT evolving; stable allele frequencies):  see p. 267
5)  Things that alter allele frequencies in a population (i.e. lead to microevolution and disrupt HW equilibrium):   a)  genetic drift:  changes that are due to chance alone (ex. bottlenecks and founder effect)
b)  gene flow (alleles come in/leave a population);  c) mutations (to a SMALL extent); and d)  natural selection (the only mechanism that consistently leads to adaptive evolution)  and there are three types:  stabilizing, disruptive, directional.  Sexual selection leads to differences in appearance (phenotype) between males and females of a species (think birds).

Chapter 14:
1)  Definitions of species:  biological, morphological, ecological, and phylogenetic (see p. 279)
2)  Speciation:  the formation of new species
3)  Reproduction barriers keep species separate:  prezygotic (there are 5); and postzygotic (there are 3)--see p. 281 Table 14.3
4)  Types of speciation:  a)  allopatric (different environments/geographic isolation occurred); and b) sympatric:  same environment; gene flow just stops or is drastically reduced (think polyploidy in plants, habitat differentiation, and sexual selection)
5)  Hybrid zones:  regions where members of diff. species meet and mate, producing at least some hybrid offspring.  Outcomes could be:   a) reinforcement; b) fusion; or c) stability
6)  Adaptive radiation (concept discussed again in chapter 15):  many diverse species arise from a common ancestor; is very common after a mass extinction because niches open up
7)  Speciation can occur slowly (gradualism model) or rapidly (punctuated equilibrium model); fossil record supports the punctuated model


Chapter 15:  I hope it is still pretty fresh on your minds.

Tonight's Reading/Work

For Review:  p. 274-275:  Number 2-11, 13

Begin reading Chapter 14:  The Origin of Species