Evolution and Mutation Concepts

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Questions and Answers

What is the process through which related species develop different traits due to different environmental pressures called?

Convergent evolution

Divergent evolution (correct)

Co-evolution

Adaptive radiation

What is microevolution primarily concerned with?

The extinction of species

Evolutionary change due to mass extinction events

Changes in allele frequencies within a population (correct)

The formation of new species

Which of the following represents an example of a structural adaptation?

Seasonal migration

Mating dances

Camouflage for hunting (correct)

Hibernation during winter

What is co-evolution?

When one species evolves in response to another species Signup and view all the answers

How do mutations contribute to evolution?

By providing random heritable changes in DNA Signup and view all the answers

Which of the following is NOT considered an environmental pressure faced by organisms?

Peer behavior Signup and view all the answers

Which adaptation allows organisms to survive by reducing metabolism?

Hibernation Signup and view all the answers

What is gene flow in the context of evolution?

The introduction of new alleles into a population Signup and view all the answers

What is a primary characteristic of natural selection?

It requires variation within a species. Signup and view all the answers

Which of the following best defines artificial selection?

The selective pressure exerted by humans on a population. Signup and view all the answers

What type of selection favors the extreme phenotypes in a population?

Disruptive selection Signup and view all the answers

What is a consequence of monoculture resulting from artificial selection?

Vulnerability to diseases and environmental changes. Signup and view all the answers

Which of the following is an example of a prezygotic mechanism?

Behavioral isolation Signup and view all the answers

What drives genetic drift in a population?

Chance events that change allele frequencies. Signup and view all the answers

Which of the following does NOT describe behavioral adaptations?

Physiological changes to tolerate temperature. Signup and view all the answers

What role does gene flow play in evolution?

It increases genetic diversity. Signup and view all the answers

Which type of selection acts when environmental changes favor one extreme phenotype over the others?

Directional selection Signup and view all the answers

What defines allopatric speciation?

Isolation caused by geographical barriers. Signup and view all the answers

What is the impact of the bottleneck effect on a population?

Decreases genetic diversity. Signup and view all the answers

Which structures provide evidence for common ancestry among different species?

Homologous structures Signup and view all the answers

What is one consequence of sexual selection?

It favors traits that enhance mating success. Signup and view all the answers

What does a vestigial structure indicate about an organism?

It was functional in its ancestors. Signup and view all the answers

Which mechanism is NOT a type of prezygotic barrier?

Hybrid inviability Signup and view all the answers

Study Notes

Evolution

Evolution is descent with modification, as defined by Charles Darwin.
Divergent evolution: Related species develop different traits due to differing environments or natural selection. Example: mammoths and elephants from Primelephas.
Microevolution: Changes in allele frequencies within populations leading to evolution.
Macroevolution: Formation of new species from existing ones.
Convergent evolution: Different species evolve similar traits due to similar environments.
Coevolution: One species evolves in response to another's evolution.
Environmental pressures: Weather, famine, space limitations, competition for resources (food, mates). Organisms overcoming these pressures are more likely to survive and reproduce.
Adaptive radiation: A common ancestor diversifies into various adapted species.

Mutation

Adaptations arise from random heritable mutations in DNA.
Mutations result from DNA replication errors or environmental mutagens (UV rays, viruses, carcinogens).
Mutations provide biological advantages.
Mutations introduce genetic variation, starting point for adaptation.
Organisms have enzymes to repair faulty DNA.
Beneficial mutations become characteristics of the species' population.
Gene flow increases genetic variation by moving alleles between populations.

Structural Adaptations

Special body features like camouflage, sharp talons, excellent vision, thick fur, thorns, or being poisonous.
Mimicry is a structural and behavioral adaptation.
Environmental pressures determine the benefit of variations within a species.

Physiological Adaptations

Allow organisms to perform specialized functions.
Hibernation: Physiological and behavioral adaptation reducing metabolism to conserve energy during harsh climates.
Antibiotic resistance in bacteria (e.g., Staphylococcus aureus).
Monarch butterflies consuming milkweed to become toxic.

Behavioural Adaptations

Actions, or behaviours, that aid survival.
Migration: Moving from one place to another.
Mating rituals (e.g., lion roars, bird dances) increase reproduction.
Mimicry is a behavioral adaptation, acting like a harmful species

Environmental Influences

Environmental stresses (droughts, floods, climate change, human activities) affect variations and drive evolution.

Natural Selection

A population's traits change over generations due to organisms with advantageous traits surviving more and reproducing.
Natural selection requires variation within the species.
Natural selection is not intentional or predictive of environmental change.

Selective Pressure

Environmental conditions favouring certain traits over others. Pressures can be abiotic (non-living, e.g., climate) or biotic (living, e.g., competition).

Fitness

An organism's contribution to the gene pool of the next generation, measured in viable offspring. Central to Darwin's theory.

Artificial Selection

Humans exert selective pressure on a population to gain or modify desirable traits.
Achieved via selective breeding.
Very fast, compared to natural selection.
Reduction of genetic diversity through monoculture (planting the same species). This makes crops vulnerable to disease and environmental issues. Health problems in animals also result.

Evidence of Evolution

Fossil record: History of different species preserved in rock layers.
Transitional fossils: Show links between groups of organisms (e.g., Archaeopteryx, dinosaur-bird characteristics).
Vestigial structures: Reduced forms of structures functional in ancestors.
Biogeography: Study of geographical distribution of organisms.
Anatomy: Studying body structures and functions, ex. vertebrates using their bones for different uses.
Homologous structures: Similar structure and origin, though function may differ.
Analogous structures: Similar function, different evolutionary origin.
Embryology: Studying early, prenatal stages of organisms.
DNA analysis: Similar DNA sequences indicate common ancestry.

Mechanisms of Evolution

Mutations introduce new alleles.
Changes in allele frequencies indicate evolution.
Gene flow: Increased genetic diversity and changes in allele frequencies. Increased genetic diversity increases survival against natural selection.
Non-random mating: Selection for phenotypes or inbreeding that increases homozygous genotypes and harmful recessive allele expression (doesn't directly affect allele frequencies). Inbreeding decreases heterozygous genotypes and increases homozygous individuals.
Genetic drift: Change in allele frequencies due to chance events, reduces variation.
Bottleneck effect: Rapid population decrease causing allele frequencies changes due to a loss in genetic diversity. (disease, starvation)
Founder effect: Small group starts new population.
Natural selection:
- Stabilizing selection: Favors intermediate phenotypes, reduces variation.
- Directional selection: Favors one extreme phenotype over another, usually when environment changes.
- Disruptive selection (diversifying): Favors extreme phenotypes, eliminating intermediates.
- Sexual selection: Natural selection for mating.

Speciation

Defining a new species involves physiology, biochemistry, behavior, and genetics.
Allopatric speciation: Geographic isolation (e.g., continental drift, islands, mountains) divides a species into separate groups.
Sympatric speciation: Populations in the same habitat diverge genetically through reproductive isolation (e.g., chromosomal changes, non-random mating).
Polyploidy in plants: Improper meiosis creates gametes with extra chromosomes leading to new species.
Prezygotic mechanisms: Prevent fertilization and zygote formation.
Postzygotic mechanisms: Prevent hybrid zygotes from becoming viable or fertile.
Prezygotic barriers: Prevent mating or fertilization.
Postzygotic barriers: After fertilization, preventing hybrid fertility.

Prezygotic Mechanisms

Behavioral isolation: Different courtship and mating cues.
Habitat isolation
Temporal isolation: Different breeding times.
Mechanical isolation: Reproductive organ differences prevent fertilization.
Gametic isolation: Gametes from different species don't recognize/fertilize each other.

Postzygotic Mechanisms

Hybrid inviability: Genetic incompatibility stops hybrid zygote development.
Hybrid sterility: Hybrid offspring are healthy but infertile.
Hybrid breakdown: F2 generation or backcross with parents are weak or infertile.

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Description

Explore the fascinating processes of evolution and mutation. This quiz covers key concepts such as divergent evolution, coevolution, adaptive radiation, and the role of mutations in adaptation. Test your knowledge on how species evolve and respond to environmental pressures.