Biology 1120: Evolution of Populations Quiz

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Questions and Answers

What is the concept that describes the genetic makeup stability in a population under specific conditions?

Hardy-Weinberg principle (correct)

Mendelian inheritance

Genetic drift

Natural selection

Which of the following factors is NOT one of the five conditions required for genetic equilibrium?

Natural selection (correct)

No mutations

Large population size

Random mating

Which statement accurately conveys the relationship between phenotypic variation and genetic variation?

Phenotypic variation often reflects genetic variation. (correct)

Phenotypic variation has no relation to genetic variation.

All phenotypic variation arises from environmental factors.

Genetic variation only shows in individuals not in populations.

What role do mutations play in a population's genetic variation?

They contribute to genetic variation by altering gene sequences. Signup and view all the answers

The understanding of diversity in organisms includes studying their interactions with what?

Each other and the environment Signup and view all the answers

What results from a genetic bottleneck in a population?

A decrease in allele frequencies compared to previous generations Signup and view all the answers

What is the founder effect?

The result of a few individuals starting a new population Signup and view all the answers

How does gene flow affect genetic variation within a population?

It generally increases variation within a recipient population Signup and view all the answers

What role does natural selection play in adaptive evolutionary change?

It conserves individuals with beneficial traits Signup and view all the answers

What did researchers discover about the genetic diversity of the Florida Panthers?

They have approximately one-third the genetic diversity of their ancestors Signup and view all the answers

What type of selection occurs when extreme phenotypes are favored and result in a decrease of intermediate phenotypes?

Disruptive selection Signup and view all the answers

Which process maintains stable frequencies of multiple phenotypic forms in a population?

Heterozygote advantage Signup and view all the answers

What does the Hardy-Weinberg principle state about the genotypes in a population at genetic equilibrium?

They occur in the frequency of $p^2 + 2pq + q^2 = 1$. Signup and view all the answers

In a scenario where a population of finches has individuals with either long beaks or short beaks thriving, while those with medium beaks do not, what effect is being observed?

Disruptive selection Signup and view all the answers

What is the expected outcome of stabilizing selection on a population's characteristics?

Reduction in phenotypic variation Signup and view all the answers

Which of the following represents the frequency of the recessive genotype (aa) in a population?

$q^2$ Signup and view all the answers

Under which condition does genetic equilibrium exist according to the Hardy-Weinberg principle?

Random mating Signup and view all the answers

When a small group of individuals becomes isolated from a larger population and establishes a new population with reduced genetic diversity, this phenomenon is referred to as what?

Founder effect Signup and view all the answers

What happens if one of the Hardy-Weinberg conditions is not met?

Microevolution occurs. Signup and view all the answers

If the frequencies of blue and green fish in a population change because the more common color is selected against, what type of selection is at play?

Frequency-dependent selection Signup and view all the answers

Which statement correctly describes heterozygote advantage in relation to malaria resistance?

Heterozygotes offer greater resistance to malaria Signup and view all the answers

In a population, if the frequency of the dominant allele (A) is 0.8, what is the frequency of the recessive allele (a)?

0.2 Signup and view all the answers

Which of the following is NOT one of the five processes of microevolution?

Phenotypic variation Signup and view all the answers

Given allele frequencies of p=0.3 and q=0.7 after a tsunami event, what microevolutionary process likely occurred?

Genetic drift Signup and view all the answers

What effect does genetic drift have on small populations?

Decreases genetic variation within the population. Signup and view all the answers

In the context of allele frequency, what does the equation $p + q = 1$ signify?

The combined frequency of dominant and recessive alleles. Signup and view all the answers

What does a gene pool represent in a population?

All the alleles for all the loci present in a population Signup and view all the answers

Which term describes the physical or chemical expression of an organism's genes?

Phenotype Signup and view all the answers

If a population has a genotype frequency of 0.49 for homozygous dominant (AA), 0.42 for heterozygous (Aa), and 0.09 for homozygous recessive (aa), what does the sum of these frequencies equal?

1.00 Signup and view all the answers

How is allele frequency defined within a population?

The proportion of a specific allele in a population Signup and view all the answers

What does genetic equilibrium indicate about a population?

There is no net change in allele or genotype frequencies over time Signup and view all the answers

In a population of 1000 individuals carrying 2000 alleles, what is the allele frequency of allele 'A' if there are 1400 instances of allele 'A'?

0.7 Signup and view all the answers

What would indicate that evolution is occurring in a population?

Change in allele frequencies over generations Signup and view all the answers

Which of the following best describes genotype frequency?

The proportion of a specific genotype in a population Signup and view all the answers

Study Notes

Biology 1120 - Professor Feely

Course name: Biology 1120
Instructor: Professor Feely
Office Hours: Holt Hall 217, Tuesdays 2-3:30 pm and Thursdays 1-2 pm. Contact for other times.

Course Information

Syllabus required
Review 21.2 due Thursday
Pearson login due Thursday
Optional EC by 28th

Course Objectives

Demonstrate knowledge of different levels of biological organization and apply it to differentiate between various taxonomic groups.
Demonstrate knowledge of evolution and apply it to various taxonomic groups.
Demonstrate knowledge of ecology at different levels of biological organization.

21.2: Evolution of Populations

Focuses on population genetics.
Covers the Hardy-Weinberg principle and conditions for equilibrium.
Explains how evolutionary forces alter allele frequencies.
Discusses the nature and extent of genetic variation in a population.

Learning Outcomes

Population genetics reviewed
Hardy-Weinberg principle defined
Five conditions for genetic equilibrium explained.
How key evolutionary forces alter allele frequencies explained.
Nature/extent of genetic variation detailed

Population Genetics

The study of genetic variation within a population
Estimates the amount of observed variation within.
Important for understanding evolutionary processes.
Gene pool includes alleles of all loci.
Diploid organisms have two alleles at each locus with Homozygous, Heterozygous.
Each individual has a unique subset of alleles.

Gene Pool Analysis

Evolution described in terms of genotype, phenotype and allele frequencies.
Genotype definition: combination of alleles in an individual.
Genotype frequency: proportion of a particular genotype in a population (expressed as a decimal).
Phenotype definition: physical or chemical expression of an organism's genes.
Phenotype frequency: proportion of a particular phenotype in a population.
Allele frequency: proportion of a specific allele (A or a) in a population.

The Hardy-Weinberg Equilibrium

Allele and genotype frequencies in a population do not change over generations unless impacted by outside forces.
Genetic equilibrium: no net change in allele or genotype frequencies over time.
Evolution is demonstrated by change in allele frequencies across generations.

Hardy-Weinberg Principle (Cont'd)

Genotypes at equilibrium occur in specific frequencies (p² + 2pq + q²= 1). - p² : frequency of AA
2pq : frequency of Aa
q² : frequency of aa

Conditions of Genetic Equilibrium

Five conditions are met for equilibrium: random mating, no net mutations, large population size, no migration, and no natural selection.
Failure of any of these leads to microevolution.

Microevolution

Changes in allele or genotype frequencies within a population over generations.
Five microevolutionary processes are detailed, opposite of genetic equilibrium.
Nonrandom mating, Mutation, Genetic drift, Gene flow and Natural selection.
Focus on the effects for example, genetic drift, genetic bottlenecks and natural selection (examples given).

Natural Selection Acts on Phenotype

Natural Selection leads to changes as populations adapt to different environments and ways of life.
Preserves and eliminates phenotypes (and their genes) that are advantageous or unfavorable.
Individuals that survive and reproduce have a selective advantage.
Different types of natural selection are detailed, including directional, stabilizing and disruptive.

Practice Questions

In corn, purple kernels are dominant, yellow. Question about phenotypic frequency or allele frequencies from given data.
Founder effect example: example question given about a flock of finches colonising a new island.
Selection in Galapagos finches: example question given about drought in Galapagos led to finches with long or short beaks.
Tsunami and rose allele frequencies: detail of a tsunami impact on a population of rose plants.

Balancing Selection

Natural selection maintains stable frequencies of two or more phenotypic forms.
Heterozygote advantage example: sickle cell allele and malaria resistance detailed in regions.

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Description

Test your understanding of population genetics and the Hardy-Weinberg principle with this quiz for Biology 1120. Explore how evolutionary forces influence allele frequencies and the genetic variation within populations. Perfect preparation for your upcoming assessments with Professor Feely.