Natural Selection and Evolutionary Concepts

Questions and Answers

What is directional selection?

A process reducing genetic diversity

A mode of natural selection favoring extreme phenotypes (correct)

A linear set of changes in organisms

The diversification into different ecological niches

What does stabilizing selection do?

Decreases genetic diversity (correct)

Increases genetic diversity

Supports extreme traits

Allows for rapid evolution

What is disruptive selection?

A mode of natural selection favoring extreme trait values over intermediate values.

Define uniformitarianism.

The theory that geological changes result from continuous and uniform processes. Signup and view all the answers

What is variational evolution?

A process of continual branching and extinction. Signup and view all the answers

Describe transformational evolution.

A linear set of changes in a single object. Signup and view all the answers

What does adaptive radiation refer to?

The diversification of a group of organisms into forms filling different ecological niches. Signup and view all the answers

What is homoplasy?

A character shared by species but not present in their common ancestor. Signup and view all the answers

Explain ecological release.

It occurs when a species is introduced to a new environment and may establish a local population or die out. Signup and view all the answers

What does 'sessile' mean?

Fixed in one place; immobile. Signup and view all the answers

Define punctuated equilibrium.

A theory suggesting species remain stable with little change for most geological history. Signup and view all the answers

What is alcohol dehydrogenase?

An enzyme that breaks down alcohol. Signup and view all the answers

Describe the founder effect.

When a group's lack of a gene leads to the entire group's lack of that gene. Signup and view all the answers

What is teleology?

The study of evidences of design in nature, or explanations by final causes. Signup and view all the answers

What is gene flow?

The transfer of alleles or genes between populations. Signup and view all the answers

Define genetic drift.

Variation in allele frequencies due to chance events in small populations. Signup and view all the answers

What is pleiotropy?

The production of multiple unrelated effects by a single gene. Signup and view all the answers

What are hitch-hiking alleles?

Alleles that change frequency due to being near another gene undergoing selection. Signup and view all the answers

What is a haplotype?

A set of DNA variations that tend to be inherited together. Signup and view all the answers

Study Notes

Natural Selection Types

Directional Selection: Favours extreme phenotypes, leading to shifts in allele frequencies over time toward that phenotype.
Stabilizing Selection: Reduces genetic diversity, stabilizing the population mean for a particular trait.
Disruptive Selection: Favours extreme trait values over intermediate ones, promoting diversity in a population.

Evolutionary Concepts

Uniformitarianism: Theory that geological changes occur through continuous and uniform processes over time.
Variational Evolution: Involves continual branching and extinction of species; differs from transformational evolution, which follows a simple, linear path.
Transformational Evolution: Refers to linear changes in a single lineage, contrasting with the branching nature of variational evolution.

Adaptive Mechanisms

Adaptive Radiation: Diversification of organisms into different forms to exploit various ecological niches.
Homoplasy: Shared traits among different species not present in their common ancestor, often due to convergent evolution.

Species Introduction and Ecology

Ecological Release: Occurs when a species is introduced to a new environment, leading to establishment or extinction.
Sessile: Describes organisms, such as barnacles, that are fixed in one place and unable to move.

Theories of Evolutionary Change

Punctuated Equilibrium: Suggests that species experience long periods of stability (stasis) interrupted by brief, significant changes.

Genetic Concepts

Alcohol Dehydrogenase: Enzyme responsible for breaking down alcohol; absence can lead to addiction.
Founder Effect: Occurs when a small group lacks a specific gene, resulting in its absence in the larger population.
Gene Flow: Transfer of alleles between populations, potentially causing notable changes in allele frequencies.
Genetic Drift: Random changes in gene frequencies, especially significant in small populations due to chance events.
Pleiotropy: A single gene affecting multiple traits, leading to diverse phenotypic expressions.
Hitch-hiking Alleles: Alleles that change frequency not due to natural selection but because of proximity to another gene under selection.
Haplotype: A combination of DNA variations inherited together, indicating the presence of linked alleles or SNPs on the same chromosome.

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Description

Explore key concepts of natural selection, including directional, stabilizing, and disruptive selection. Understand evolutionary theories such as uniformitarianism and variational evolution, along with adaptive mechanisms like adaptive radiation. This quiz will test your knowledge of how these principles shape biodiversity.