Evolutionary Processes & Hardy-Weinberg Equilibrium

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Questions and Answers

What best explains the variation in male and female mallard ducks' coloration?

Stabilizing selection

Directional selection

Disruptive selection (correct)

Divergent evolution

Which factor is necessary to maintain allelic frequencies in a Hardy-Weinberg population model?

Natural selection

Frequent mutation

Random mating (correct)

Genetic drift

What term describes barriers to successful interbreeding between species within the same community?

Adaptive radiation

Geographic isolation

Reproductive isolation (correct)

Sexual dependency

The similarity in the underlying anatomy of bat wings and human arms suggests they are examples of what?

Homology Signup and view all the answers

In a population at Hardy-Weinberg equilibrium, if the frequency of a recessive allele is 0.4, what percentage of the population is heterozygous for that allele?

48% Signup and view all the answers

According to the Hardy-Weinberg equation, how is the dominant trait represented?

p Signup and view all the answers

The differences in sparrow songs among sympatric species of sparrows illustrate which concept?

Behavioral isolation Signup and view all the answers

Which of the following is an evolutionary process not based on random factors?

Natural selection Signup and view all the answers

Which of the following is not a sexually selected trait?

Fruit fly wings Signup and view all the answers

Which of the following is not a requirement for natural selection to occur?

Sexual reproduction Signup and view all the answers

Why can Hardy-Weinberg equilibrium occur only in large populations?

Genetic drift is a much stronger force in small versus large populations. Signup and view all the answers

What are the frequencies of the p and q alleles in a population of frogs consisting of 9 percent with speckles (the recessive condition) and 91 percent without speckles?

p = 0.49, q = 0.51 Signup and view all the answers

Frequency-dependent selection is one way in which multiple alleles are preserved in a population. What is a false statement about it?

It is possible only when there are two alleles. Signup and view all the answers

Which of the following provides no evidence for evolution?

Artificial selection Signup and view all the answers

Why do we assume that oxygen was not present in the original atmosphere?

Inorganic molecules could not have formed in the presence of oxygen. Signup and view all the answers

Study Notes

Evolutionary Processes & Principles

Non-random evolutionary processes: Natural selection, gene flow.
Random evolutionary processes: Mutation, genetic drift, bottlenecks.
Sexual selection traits: Male baboon canine teeth, peacock tail feathers, male/female size dimorphism in many species.
Adaptations: Can be shaped by genetic drift, affect fitness if altered, can be deleterious, do not guarantee mating success.
Requirements for natural selection: Variation between individuals, heritable trait, differences in reproductive success. Sexual reproduction is not a requirement for natural selection but is for reproduction of the trait itself.

Hardy-Weinberg Equilibrium

Large populations & equilibrium: Genetic drift is stronger in small populations. Random mating is more likely in large populations.
Conditions for Hardy-Weinberg equilibrium:
- No mutations
- Random mating
- No gene flow
- No genetic drift
- No natural selection
Frequency of alleles (p and q) in equilibrium: Ex. 9% speckles (recessive) , 91% no speckles (dominant) determines p & q values.

Other Evolutionary Concepts

Frequency-dependent selection: Preserves multiple alleles. Crucial during speciation
Evidence for evolution: Vestigial characters, Darwin's finches, homologous characters, embryology.
Absence of oxygen in early atmosphere: Inorganic molecules could form without oxygen.
Random evolutionary processes example: earthquake separating a population, a mutation that changes characteristics, a new environment that causes a population’s home range to shift.

Selection Types

Disruptive selection: Not the one highlighted in the selected text.
Directional selection: Not the one highlighted in the selected text.
Stabilizing selection: Not the one highlighted in the selected text.

Maintaining Allelic Frequencies

Hardy-Weinberg equilibrium & alleles: Requires random mating; Natural selection and genetic drift disrupt equilibrium
Reproductive isolation: Prevents interbreeding between species in the same community, a key concept in speciation.

Evolutionary Structures

Homologous structures: Bat wings and human arms, similar underlying anatomy despite different functions, evidence of shared ancestry.
Analogous structures: Not in the text.

Hardy-Weinberg Calculations

Heterozygous individuals: Using the Hardy-Weinberg equation, the percentage of the population that is heterozygous for a certain allele can be determined.
Allele Frequency Calculation Using the frequencies, p and q, you can find the frequency of heterozygous genotypes in populations.
Hardy-Weinberg equation Variables:
- p represents the frequency of the dominant allele.
- q represents the frequency of the recessive allele.
- p2 represents the frequency of homozygous dominant individuals.
- q2 represents the frequency of homozygous recessive individuals.
- 2pq represents the frequency of heterozygous individuals.
- p + q = 1

Isolation Mechanisms

Behavioral isolation: Examples include differences in courtship rituals between species, like sparrow songs.

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Description

Explore the essential concepts of evolutionary processes and the Hardy-Weinberg equilibrium. This quiz covers both non-random and random evolutionary processes, adaptations, and the key requirements for natural selection. Test your understanding of genetic principles and the conditions that maintain genetic equilibrium in populations.