Evolution - General Overview

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Questions and Answers

What is the primary reason altruists would disappear from a population?

They travel to different environments.

They consume too much of the resources.

They become less beneficial over time.

Non-altruists benefit without sharing costs. (correct)

What does reciprocal altruism illustrate in animal behavior?

Only related animals engage in altruistic acts.

Animals cooperate for mutual benefits. (correct)

Altruism leads to higher reproductive success.

Help is always given unconditionally.

Which of the following best defines inclusive fitness?

The total number of an organism's offspring.

The ability to survive in changing environments.

The reproductive success within sterile castes.

The combined measure of direct and indirect fitness. (correct)

What happens to a vampire bat that is caught cheating in blood sharing?

It faces abandonment by its partners. Signup and view all the answers

How do closely related organisms influence the decision to help each other reproduce?

They share a significant proportion of alleles. Signup and view all the answers

What is a characteristic of sterile castes in eusocial insects?

They support the reproductive efforts of the queen. Signup and view all the answers

Why can altruistic behaviors be classified as selfish in many instances?

They typically lead to immediate rewards for the altruist. Signup and view all the answers

What did J.B.S. Haldane imply about his willingness to sacrifice himself?

He values genetic relationships in determining sacrifice. Signup and view all the answers

What does natural selection primarily target in a population?

Allowing organisms to adapt to their current environment Signup and view all the answers

What concept explains the limitations of moving from a local optimum to a global optimum in evolution?

Adaptive landscape Signup and view all the answers

What is the definition of a mutation in genetics?

A change in a gene Signup and view all the answers

How does natural selection influence the evolution of complex traits?

Complex traits must evolve through viable intermediates Signup and view all the answers

What is a heterozygous individual?

An organism with two different alleles at a locus Signup and view all the answers

What does the term 'exaptation' refer to in evolutionary biology?

A trait that evolved for one purpose but is used for another Signup and view all the answers

Why might 'half a wing' evolve despite seeming non-functional for flight?

It has potential alternative uses that confer advantages Signup and view all the answers

Which of the following statements about allelic variation is true?

Alleles can exist in more than two forms in a population Signup and view all the answers

What is one of the key misunderstandings about how natural selection operates?

Natural selection is a force similar to gravity Signup and view all the answers

What does linkage disequilibrium measure?

The association between alleles of two different genes Signup and view all the answers

What is the main role of natural selection in evolution?

To act on existing genetic variation Signup and view all the answers

What role do mutations play in the process of natural selection?

Mutations introduce changes that could potentially enhance reproductive success Signup and view all the answers

What is meant by a trait's 'current utility' in evolutionary terms?

How the trait functions in the modern environment Signup and view all the answers

Which statement best describes the term 'homozygous'?

Possessing two identical alleles at a locus Signup and view all the answers

What is the typical level of polymorphism in birds?

15% of loci having multiple alleles Signup and view all the answers

What percentage of loci in plants typically have more than one allele?

45% Signup and view all the answers

What is the primary focus of sexual selection in natural selection?

Factors contributing to an organism's mating success Signup and view all the answers

Which of the following is an example of sexual dimorphism resulting from sexual selection?

Bright plumage in male birds compared to females Signup and view all the answers

What does the good genes model suggest about male displays?

They signal male fitness and absence of parasites Signup and view all the answers

What do critics argue about species selection?

It lacks theoretical probability of occurrence. Signup and view all the answers

How can traits that are detrimental to survival nevertheless persist in a population?

They enhance mating success sufficiently to offset survival costs Signup and view all the answers

What type of competition occurs when males compete for females in polygynous species?

Competition driven solely by female choice and preference Signup and view all the answers

What has been shown to be true about the number of species produced over time?

It is significantly less than the amount of different alleles. Signup and view all the answers

What phenomenon does the presence of polymorphisms within some species indicate?

Morphological changes can occur without speciation. Signup and view all the answers

What did Milinski and Bakker’s research on sticklebacks demonstrate?

Male coloration correlates with parasite load and attractiveness Signup and view all the answers

Which aspect of evolution do population geneticists focus on?

The process as it is currently occurring. Signup and view all the answers

Which statement characterizes the runaway sexual selection model?

It suggests that certain traits evolve purely due to female preference for extremes. Signup and view all the answers

What implication does the concept of sexual selection have on the evolution of species?

It highlights the importance of reproductive success over survival traits. Signup and view all the answers

Which molecule is suggested to be the first replicating molecule in the history of life?

RNA Signup and view all the answers

What role do certain RNA sequences play according to laboratory studies?

They act as polymerases forming RNA strands. Signup and view all the answers

How do the rates of evolution change over time according to the content?

They vary over time, which is widely accepted. Signup and view all the answers

What distinguishes phenotypic changes from evolutionary changes?

Phenotypic changes are not heritable. Signup and view all the answers

Why might the scientific narrative of evolutionary history be incomplete?

The more remote the time, the less certain the information is. Signup and view all the answers

How does evolution relate to the environment?

Evolution involves adapting to current surroundings without a notion of progress. Signup and view all the answers

What was demonstrated by Paquin and Adams in their yeast culture experiment?

Competitive ability can fluctuate over time based on the environment. Signup and view all the answers

Which statement about species and their environments is true?

Species can modify their environment to support their survival. Signup and view all the answers

What role does genetic variation play in evolution?

It is necessary for evolution to occur. Signup and view all the answers

How can environmental changes impact species' competitiveness?

Species may need to migrate to maintain competitiveness. Signup and view all the answers

What can be concluded about the success of traits over time?

A trait successful at one time may fail at another. Signup and view all the answers

Which of the following is NOT a characteristic of evolution?

It is a directional process toward complexity. Signup and view all the answers

Signup and view all the answers

Study Notes

Evolution- General 1

Evolution is the cornerstone of modern biology, uniting all fields under one theoretical umbrella.
A common misconception is arranging species on an evolutionary ladder.
Evolution is a change in the gene pool of a population over time.
A gene is a hereditary unit passed down unaltered.
The gene pool is all the genes in a species or population.
The English moth, Biston betularia, exemplifies observed evolution. Dark moths increased in frequency during the Industrial Revolution due to natural selection. Dark moths survived better on darkened birch trees.

What is Evolution?

Evolution is a change in the gene pool of a population over time.
A gene is a hereditary unit.
The gene pool is all the genes in a population or species.

Common Misconceptions about Evolution

Evolution can occur without morphological change.
Morphological change can occur without evolution.
Phenotype is an organism's observable characteristics.
Phenotype depends on genes and environment.
Evolution is not progress, but adaptation to current surroundings.
Natural selection may not necessarily lead to better traits in the long term

Genetic Variation

Evolution requires genetic variation.
Mutation is a change in a gene, creating new genetic variation.
Alleles are different versions of a gene (created by mutation).
Allelic diversity and non-random associations of alleles are components of genetic variation.
Considerable variation exists in natural populations.
Linkage disequilibrium is the association between alleles of different genes found together more often than expected.

Natural Selection

Natural selection is the only mechanism of adaptive evolution.
Natural Selection is defined as differential reproductive success of existing genetic variants in a gene pool.
Selection weeds out deleterious alleles or causes an allele to sweep to fixation.
Balancing selection maintains genetic variation when heterozygotes are more fit than homozygotes.
Sickle-cell anemia is an example of balancing selection. Heterozygotes are resistant to malaria, but homozygotes have anemia.
Organisms do not behave for the good of their species, but for their own survival and reproduction.

Sexual Selection

Sexual selection is natural selection acting on factors contributing to mating success.
Sexual traits can be detrimental to survival but outweigh the survival liability due to attracting more mates.
Examples of sexual selection include the peacock's tail, the colors and patterns of male birds, calls of frogs, and flashes of fireflies.

Genetic Drift

Allele frequencies can change due to chance. This is known as genetic drift. A binomial sampling error.
Drift is significant in small populations
In small populations, the variance in allele frequency change is greater than in larger populations.
The overall rate of genetic drift (measured in substitutions per generation) is independent of population size.

Mechanisms that Decrease Genetic Variation

Natural selection.
Genetic drift.

Mechanisms that Increase Genetic Variation

Mutation.
Recombination.
Gene flow.

The Fate of Mutant Alleles

Most new alleles are lost, and only a small percentage fix.
Neutral alleles change frequency due to chance alone.
Fixation (an allele's frequency reaching or near 100%) is a process.
The probability of fixation of a neutral allele is equal to its frequency.

Directional Selection

Directional selection depletes genetic variation at the selected loci.
Sequences can hitchhike with alleles due to low recombination rates.

Recombination

Recombination creates new combinations of alleles from the mother and the father.

Gene Flow

New organisms from other populations can introduce new alleles to the local gene pool.
This is called gene flow.
Gene flow affects populations by increasing variation.

Speciation

Speciation is the process of a single species becoming two or more species.
Allopatric speciation occurs when a population is geographically divided into isolated subpopulations.
Sympatric speciation occurs when subpopulations become reproductively isolated without first being geographically isolated.

Extinction

Extinction is the fate of all species
Ordinary extinction is the demise of a species due to competition with related species, habitat loss, or the development of an unbeatable defense.
Mass extinction is the widespread and rapid disappearance of many species simultaneously.

Punctuated Equilibrium

Punctuated equilibrium proposes that most macroevolutionary change occurs quickly during speciation events rather than gradually.
Gaps in the fossil record where transitional forms are not found are cited as evidence.

The Modern Synthesis of Genetics and Evolution

The modern synthesis combines Darwin's theory of natural selection with Mendelian genetics.
It recognizes multiple mechanisms of evolution (including genetic drift), discrete genes, and gradual accumulation of small genetic changes as the basis of macroevolution.

Some Books about Biology and Evolution

(List of books provided)

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Description

Explore the fundamental concepts of evolution, the changes in the gene pool over time, and common misconceptions surrounding the topic. This quiz covers the significance of evolution in biology and examples like the English moth, Biston betularia, showcasing natural selection. Test your understanding of these essential principles.