AP Bio Unit 7 - Evolution & Phylogeny

basics of evolution, speciation, evolution of a population, phylogeny and systematics

What are the 4 elements of natural selection

variation exists in a population, overpopulation of offspring, competition, differential survival, differential reproductional

evidence of evolution

fossil record, anatomical record, molecular record

homologous structures

same components, but for different use

Vestigial structures

once had a purpose, but not anymore

Analogous structures

similar functions, but different origins bc convergent evolution

Convergent

species evolve and select similar traits

Divergent

species have a common ancestor

species

population whose members can interbreed and produce offspring

Allopatric isolation

geographic separation

Sympatric isolation

still live in the same area, but have reproductive barriers

6 pre-reproduction barriers

geographic, ecological, temporal, behavioral, mechanical, and gametic

geographic isolation

species occur in different areas

Ecological isolation

species occur in same region, but different habitats so don’t interact

Temporal isolation

species that breed during times of day

Behavioral isolation

different behavioral patterns and rituals (can’t attract male)

Mechanical isolation

their parts don’t fit

gametic isolation

sperm of one species can’t fertilize the eggs of another species

biochemical barrier

gametic isolation due bc sperm can’t penetrate egg

Chemical incompatibility

gametic isolation due bc sperm can’t survive in female

Post-reproduction barriers

decreased hybrid viability, hybrid fertility, hybrid breakdown

hybrid viability

genes of parents impaired hybrid development

Hybrid fertility

chromosomes in parents vary leading to being sterile

hybrid breakdown

hybrids are fertile and viable in the 1st generation, but offspring are feeble or sterile

Populations evolve bc

survival of the fittest and differential reproductive success (who bears more offspring)

Variation

raw material of natural selection

Mutation

cause of variation; random changes in DNA (errors in mitosis and meiosis)

Sex

cause of variation; mixing of alleles which lead to new combos and new phenotypes

5 agents of evolutionary change

mutation & variation, gene flow, non-random mating, genetic drift, natural selection

gene flow

movement of individuals and alleles in and out of populations (ex. Pollen traveling by wind and insects)

Non-random mating

organisms picking who they believe is the fittest

genetic drift

effect of chance events

Founder effect

small group splinters off and starts new colony

bottleneck effect

disaster reduces population to small number then population recovers and expands again

Genetic equilibrium requires

no mutations, large population, no gene flow, random mating, all individuals survive and reproduce equally

hardy weinberg is used to

determine genetic equilibrium

hardy weinberg genotypic frequencies

p^2 + 2pq + q^2 = 1.0 (AA + Aa + aa = 1.0)

Hardy weinberg allele frequencies

p + q = 1.0

phylogeny

evolutionary history of a species

Systematics

connects classification system to phylogeny by categorizing and naming organisms

Build phylogenies with

morphological and molecular homologies

Evaluating molecular homologies by

aligning DNA sequence and more bases in common means species are closely related

Cladograms

patterns of shared characteristics

Principle of parsimony

simplest explanation and fewest evolutionary events that explain data

3 domains of the Universal tree of life

bacteria, Eukarya, Archaea