evolution frqs

Explain the principles of natural selection and give a real-world example.

Natural selection is the process where organisms with advantageous traits are more likely to survive and reproduce. Principles include: Variation (individuals in a population vary), Inheritance (traits are passed from parents to offspring), Selection (some traits provide a survival/reproductive advantage), and Time (evolution occurs over generations). Example: Peppered moths during the Industrial Revolution. Initially, light-colored moths were more common due to camouflage. Pollution darkened tree bark, making dark-colored moths better camouflaged, leading to a higher survival rate.

Explain how diversity within a species results in increased fitness.

Diversity increases fitness because different traits help organisms survive in changing environments. A population with high genetic diversity is more likely to have some individuals that can survive and reproduce when conditions change. This is \"survival of the fittest,\" where fitness refers to reproductive success.

List factors contributing to genetic variation and identify the 'ultimate' source.

Factors contributing to genetic variation include: Mutation (random changes in DNA, ultimate source), Gene Flow (movement of genes between populations), Sexual Reproduction (new combinations of genes), and Genetic Drift (random changes in allele frequencies). Mutation is considered the “ultimate” source because it is the origin of new alleles.

Explain the phrase, 'Individuals don't evolve, populations do.'

Individuals do not evolve because their genetic makeup remains constant during their lifetime. Evolution occurs at the population level, where the proportion of different genetic variants (alleles) changes over generations due to natural selection, genetic drift, etc.

Describe and sketch the three modes of selection.

Modes of selection include: Directional Selection (favors one extreme phenotype), Disruptive Selection (favors both extreme phenotypes, leading to two or more distinct groups), and Stabilizing Selection (favors intermediate phenotypes). (Imagine sketches illustrating each mode, with graphs showing phenotype distribution before and after selection).

Describe at least three mechanisms of microevolution.

Mechanisms of microevolution include: Natural Selection (differential survival/reproduction based on traits), Genetic Drift (random changes in allele frequencies), Gene Flow (migration of genes between populations), and Mutation (introduction of new alleles).

Explain why genetic drift impacts smaller populations more.

Genetic drift has a bigger impact on smaller populations because random events can significantly alter allele frequencies. In a small population, losing a few individuals can remove alleles entirely. In a large population, the same loss would have a minimal effect on overall allele frequencies.

List the conditions for evolution to not occur.

1. Population is large. 

2. Must be random mating.

3. No migration.

4. No mutations.

5. No natural selection

Differentiate between speciation and extinction.

Speciation is the process by which new species arise. Extinction is the process by which species cease to exist. Speciation increases diversity, while extinction reduces it.

Explain why isolation is necessary for speciation.

Isolation is necessary for speciation because it prevents gene flow between groups. Without gene flow, genetic differences can accumulate due to natural selection, mutation, and genetic drift, eventually leading to reproductive isolation and the formation of new species.

Differentiate between gradual and mass extinction.

Gradual extinction occurs slowly over long periods due to environmental changes or other factors. Mass extinction is a rapid and widespread event that eliminates a large percentage of species on Earth.

Differentiate between gradualism and punctuated equilibrium.

Gradualism is the theory that evolution occurs slowly and steadily over time. Punctuated equilibrium is the theory that evolution occurs in bursts of rapid change separated by long periods of stasis.

Differentiate between divergent and convergent evolution.

Divergent evolution is when related species evolve different traits due to different environments or selective pressures (e.g., Darwin's finches). Convergent evolution is when unrelated species evolve similar traits due to similar environments or selective pressures (e.g., the wings of bats and insects).

Explain the significance of coevolution.

Coevolution is the process where two species evolve in response to each other. This often occurs in symbiotic relationships, such as between pollinators and flowering plants, where each species exerts selective pressure on the other.

Distinguish the three domains of life and list other taxonomic levels.

The three domains are:Eubacteria = prokaryotes; “true” bacteria, like pathogens

• Archaebacteria = prokaryotes in extreme environments

• Eukarya. Other taxonomic levels are: Kingdom, Phylum, Class, Order, Family, Genus, and Species.

Explain the role of transitional fossils.

Transitional fossils show intermediate forms between ancestral groups and their descendants. They provide evidence of how major evolutionary changes occurred over time, filling gaps in the fossil record.

Explain the differences between homologous, analogous, and vestigial structures.

Homologous structures have a common ancestry but different functions (e.g., the forelimbs of mammals). Analogous structures have similar functions but different ancestries (e.g., the wings of birds and insects, product of convergent evolution). Vestigial structures are remnants of structures that had a function in an ancestor but no longer do (e.g., the human appendix. Homologous structures result from divergent evolution, analogous from convergent evolution.

Summarize the endosymbiotic theory.

The endosymbiotic theory proposes that mitochondria and chloroplasts were once free-living prokaryotes that were engulfed by larger cells and developed a symbiotic relationship. Key evidence includes their double membranes, independent DNA, and ribosome structure.

Explain how taxonomy and phylogeny are similar yet unique.

Taxonomy is the science of classifying organisms. Phylogeny is the study of the evolutionary relationships among organisms. Taxonomy uses phylogeny to create classifications that reflect evolutionary history.

Explain what phylogenetic trees show and what evidence is used to construct them.

Phylogenetic trees show the evolutionary relationships among organisms. They are constructed using evidence from morphology, genetics, and behavior. They visually depicts common ancestery and how closely related the species are.

Describe how biogeography and embryology provide evidence for evolution.

Biogeography (the study of the geographic distribution of species) shows how species are distributed based on their evolutionary history and continental drift. Embryology (the study of embryo development) reveals similarities in early development among different species, indicating common ancestry.

List the two macromolecules that provide evidence for evolution in biochemistry.

The two macromolecules that provide evidence for evolution in biochemistry are DNA and proteins. Similarities in DNA and protein sequences indicate evolutionary relationships.

List two things we can and cannot learn from a phylogenetic tree.

From a phylogenetic tree, we can learn: (1) which species are most closely related, and (2) the order in which different lineages diverged. We cannot learn: (1) the absolute ages of the species, and (2) the rate of evolution.

Describe an example of direct observation providing evidence for evolution.

An example of direct observation is the evolution of antibiotic resistance in bacteria. Over time, bacteria exposed to antibiotics evolve resistance mechanisms, demonstrating evolution in real-time.