Unit 5: Evolution of Species and Populations

What are the three domains of life?

Archaea, Bacteria, Eukarya

What are the characteristics of Domain Archaea?

Prokaryotic, unicellular, autotroph or heterotroph, varied cell walls, asexual, example: methanobacteria

What are the characteristics of Domain Bacteria?

Prokaryotic, unicellular, autotroph or heterotroph, peptidoglycan cell walls, asexual, examples: E. coli, Salmonella

What are the characteristics of Domain Eukarya?

Eukaryotic, mostly multicellular, autotroph or heterotroph, varied cell walls, sexual/asexual, examples: trees, birds

What distinguishes the Protista kingdom?

Mostly unicellular, some multicellular, autotroph/heterotroph, pectin or no cell wall, examples: amoebas, algae

What distinguishes the Fungi kingdom?

Mostly multicellular, heterotroph, chitin cell wall, examples: mushrooms, yeasts

What distinguishes the Plantae kingdom?

Multicellular, autotroph, cellulose cell wall, examples: trees, flowers

What distinguishes the Animalia kingdom?

Multicellular, heterotroph, no cell wall, examples: humans, worms

What are the key components of natural selection?

Variation, inheritance, overproduction, differential survival, adaptation

What is the result of natural selection?

Traits that improve survival become more common over generations.

What is strata in geology?

Rock layers; oldest at the bottom, youngest at top

Why is the fossil record incomplete?

Not all organisms fossilize; erosion or other forces destroy fossils.

What are homologies?

Similar structures from a common ancestor

How do mutations and sexual reproduction cause genetic variation?

Mutations add new alleles; sex shuffles alleles into new combos.

Define: Gene Pool, Population, Microevolution

Gene Pool: All alleles in a population; Population: Group of same species in one area; Microevolution: Small changes in allele frequencies

What are the 5 Hardy-Weinberg conditions?

Large population, Random mating, No migration, No mutations, No natural selection

What is genetic drift?

Random change in allele frequencies

What is gene flow?

Movement of alleles between populations

What is the bottleneck effect?

Sharp reduction in population size = less diversity

What is the founder effect?

Small group colonizes new area = less diversity

Why is natural selection unique?

It’s the only mechanism that consistently increases adaptation.

Compare stabilizing, directional, and disruptive selection.

Stabilizing: favors average; Directional: favors one extreme; Disruptive: favors both extremes

What’s the difference between intrasexual and intersexual selection?

Intrasexual: same sex competes; Intersexual: one sex chooses

How does antibiotic resistance evolve?

Bacteria with resistant mutations survive and reproduce.

What’s the difference between microevolution and speciation?

Microevolution = small allele changes; Speciation = new species forms

What are prezygotic barriers?

Prevent fertilization: habitat, temporal, behavioral, mechanical, gamete isolation

What are postzygotic barriers?

After fertilization: inviability, sterility, breakdown

What is allopatric speciation?

Speciation due to geographic isolation

What is sympatric speciation?

Speciation in the same location (e.g., polyploidy in plants)

What is adaptive radiation?

One species evolves into many to fill niches (e.g., Darwin's finches)

Compare punctuated equilibrium and gradualism.

Punctuated: sudden changes; Gradualism: slow, steady changes

What is the goal of taxonomy?

Organize and classify organisms by relationships

What are the taxonomic ranks?

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Homologous vs. Analogous structures?

Homologous: same origin, different function; Analogous: different origin, same function

What is convergent evolution?

Unrelated species evolve similar traits

What is divergent evolution?

Related species become different over time

What does a cladogram show?

Evolutionary relationships based on shared traits

What is an outgroup in a cladogram?

The least related group used as a reference