BIO 1 Final Exam Cram

How are macroevolution and microevolution related?

Micro = allele frequency changes; Macro = speciation/large-scale evolution; Micro changes accumulate into macro.

How do reproductive barriers lead to speciation?

Prevent gene flow → populations diverge → new species form.

Distinguish between allopatric and sympatric speciation.

Allopatric = geographic isolation; Sympatric = no geographic isolation (often polyploidy).

How can polyploidy contribute to sympatric speciation?

Extra chromosome sets → reproductive isolation → new species.

What are diagnostic traits?

Unique traits used to identify and distinguish species.

How can the fossil record support both gradualism and punctuated equilibrium?

Gradualism = slow continuous change; Punctuated equilibrium = long stability + rapid speciation.

What factors can cause or hasten extinction?

Habitat loss, invasive species, pollution, overexploitation, climate change, continental drift, meteorites.

How have humans influenced extinctions?

Habitat destruction, deforestation, pollution, overfishing/hunting, invasive species, climate change.

Describe prezygotic barriers and postzygotic barriers.

Prezygotic = prevent fertilization; Postzygotic = offspring die, are sterile, or have low fitness.

What five conditions are required for Hardy-Weinberg equilibrium?

No mutations; No gene flow; Random mating; No genetic drift; No natural selection.

Explain p + q = 1 and p² + 2pq + q² = 1.

p = dominant allele; q = recessive allele; p² = homozygous dominant; 2pq = heterozygous; q² = homozygous recessive.

Distinguish between directional, disruptive, and stabilizing selection.

Directional = one extreme favored; Stabilizing = average favored; Disruptive = both extremes favored.

How do mutations affect an organism's phenotype?

Create new alleles; phenotype may change; beneficial, harmful, or neutral.

Under what conditions does a mutation pass to subsequent generations?

Only if it occurs in gametes (sex cells).

How does sampling error lead to genetic drift?

Chance changes allele frequencies, especially in small populations.

What is the difference between the founder effect and a population bottleneck?

Founder = few individuals start new population; Bottleneck = population drastically reduced.

How do nonrandom mating and migration result in evolutionary change?

Nonrandom mating changes genotype frequencies; Migration (gene flow) moves alleles between populations.

How does global climate change threaten biodiversity?

Habitat shifts, warming, coral bleaching, more extinctions.

What is the value of diversity to humans and ecosystems as a whole?

Medicine, food, pollination, nutrient cycling, climate regulation, ecosystem stability.

Describe the three types of biodiversity.

Genetic diversity; Species diversity; Ecosystem diversity.

Differentiate among extinct, endangered, and vulnerable species.

Extinct = gone; Endangered = high extinction risk; Vulnerable = likely to become endangered.

Which human activities account for most of the loss of terrestrial habitat?

Urban sprawl, agriculture, deforestation, mining, development.

How do dams and channelization alter river ecosystems?

Alter flow, trap sediment, harm wildlife, reduce habitat diversity.

Why is damage to estuaries and coastlines especially devastating?

Loss of nurseries, wetlands, flood protection, erosion control, biodiversity.

How do pollutants affect aquatic ecosystems?

Contaminate water, biological magnification, kill organisms, disrupt food webs.

How does human population growth affect conservation biology?

More resource use, pollution, habitat loss, biodiversity decline.

How can scientists, governments, and ordinary citizens work together for conservation?

Research; laws/protected areas; recycle, conserve resources, reduce pollution.

What can homologies reveal about evolution?

Common ancestry.

What is a vestigial structure? Examples?

Reduced ancestral structure; examples: appendix, tailbone, whale pelvis, snake leg bones.

How does embryonic development reveal shared evolutionary history?

Similar embryos suggest common ancestry.

How does analysis of DNA and proteins support evolution?

More similar DNA/proteins = closer evolutionary relationship.

How can molecular clocks help determine when two species diverged?

Compare mutation rates to estimate divergence time.