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Ch. 26 - Population and Evolutionary Genetics
Chapter 25, Problem 2

Write a short essay describing the roles of mutation, migration, and selection in bringing about speciation.

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Start by defining speciation, which is the process by which populations evolve to become distinct species.
Explain the role of mutation in speciation: Mutations introduce genetic variation by altering DNA sequences, which can lead to new traits that may be advantageous, neutral, or deleterious.
Discuss migration (gene flow) and its impact: Migration involves the movement of individuals between populations, which can introduce new genetic material and increase genetic diversity, potentially leading to speciation if populations become isolated.
Describe natural selection and its influence: Natural selection acts on genetic variation, favoring traits that enhance survival and reproduction, which can lead to the accumulation of differences between populations over time.
Conclude by explaining how the interplay of mutation, migration, and selection can lead to reproductive isolation, a key factor in the formation of new species.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Mutation

Mutation refers to changes in the DNA sequence of an organism's genome. These alterations can occur spontaneously or be induced by environmental factors. Mutations introduce genetic variation, which is essential for evolution, as they can lead to new traits that may be advantageous, neutral, or deleterious. Over time, beneficial mutations can accumulate, contributing to the divergence of populations and the formation of new species.
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Migration

Migration, or gene flow, is the movement of individuals and their genetic material between populations. This process can introduce new alleles into a population, increasing genetic diversity. When populations migrate and interbreed, they can share beneficial traits, but if populations become isolated, migration can also lead to distinct evolutionary paths. This isolation is a key factor in speciation, as it can result in the development of unique adaptations in different environments.
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Selection

Natural selection is the process by which certain traits become more common in a population due to their advantageous effects on survival and reproduction. Organisms with favorable traits are more likely to survive and reproduce, passing those traits to the next generation. Over time, selection can lead to significant changes in a population's genetic makeup, driving speciation as populations adapt to different ecological niches or environmental pressures, ultimately leading to the emergence of new species.
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Related Practice
Textbook Question

Population geneticists study changes in the nature and amount of genetic variation in populations, the distribution of different genotypes, and how forces such as selection and drift act on genetic variation to bring about evolutionary change in populations and the formation of new species. From the explanation given in the chapter, what answers would you propose to the following fundamental questions?

How do we know whether the genetic structure of a population is static or dynamic?

363
views
Textbook Question

Population geneticists study changes in the nature and amount of genetic variation in populations, the distribution of different genotypes, and how forces such as selection and drift act on genetic variation to bring about evolutionary change in populations and the formation of new species. From the explanation given in the chapter, what answers would you propose to the following fundamental questions?

How do we know when populations have diverged to the point that they form two different species?

421
views
Textbook Question

Population geneticists study changes in the nature and amount of genetic variation in populations, the distribution of different genotypes, and how forces such as selection and drift act on genetic variation to bring about evolutionary change in populations and the formation of new species. From the explanation given in the chapter, what answers would you propose to the following fundamental questions?

How do we know the age of the last common ancestor shared by two species?

318
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Textbook Question

Consider rare disorders in a population caused by an autosomal recessive mutation. From the frequencies of the disorder in the population given, calculate the percentage of heterozygous carriers:

0.0064

259
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Textbook Question

Consider rare disorders in a population caused by an autosomal recessive mutation. From the frequencies of the disorder in the population given, calculate the percentage of heterozygous carriers:

0.000081

240
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Textbook Question

Consider rare disorders in a population caused by an autosomal recessive mutation. From the frequencies of the disorder in the population given, calculate the percentage of heterozygous carriers:

0.09

263
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