In what sense is natural selection more “predictable” than genetic drift?

Short Answer

Expert verified

Natural selection allows change in allele frequencies in a random way, which increases the reproductivity of the population. However, genetic drift occurs by chance, and it can decrease or increase the allele frequency. Thus, natural selection is more predictable than genetic drift.

Step by step solution

01

Natural selection

Natural selection is the evolutionary force that acts on the population to increase its survival in the environment. It allows adaptation in organisms, which increases the population. Natural selection only occurs when the population possesses an inheritable variation.

02

Genetic drift

The change in allele frequency causes genetic drift in the population. Migration, mutation, or random mating bring changes in allele frequencies and cause genetic drift. A small population caused by genetic drift is more likely to go extinct. Founder effect and bottleneck effect are two forms of genetic drift.

03

The reasons that make genetic drift unpredictable

Allele frequencies are constantly changing in a population for better adaptation.Genetic drift is an evolutionary process that causes speciation and genetic variation in species.

However, genetic drift does not increase the degree of adaptation in an individual or population. It alters the allele frequency in such a way that it may be harmful or beneficial to the population.

It is not necessary that a change in allele frequency in a population will lead to genetic drift. However, the inheritable changes in allele frequencies always go through natural selection. Therefore, natural selection is more predictable.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Explain why genetic variation within a population is a prerequisite for evolution?

Using at least two examples, explain how the process of evolution is revealed by the imperfections of living organisms.

Researchers studied genetic variation in the marine mussel Mytilus edulis around Long Island, New York. They measured the frequency of a particular allele (lap 94) for an enzyme involved in regulating the mussel’s internal saltwater balance. The researchers presented their data as a series of pie charts linked to sampling sites within Long Island Sound, where the salinity is highly variable, and along the coast of the open ocean, where salinity is constant. (a) Create a data table for the 11 sampling sites by estimating the frequency of lap 94 from the pie charts. (Hint: Think of each pie chart as a clock face to help you estimate the proportion of the shaded area.) (b) Graph the frequencies for sites 1–8 to show how the frequency of this allele changes with increasing salinity in Long Island Sound (from southwest to northeast). Evaluate how the data from sites 9–11 compared with the data from the sites within the Sound. (c) Considering the various mechanisms that can alter allele frequency, construct a hypothesis that explains the patterns you observe in the data and that accounts for the following observations: (1) The lap94 allele helps mussels maintain osmotic balance in water with a high salt concentration but is costly to use in less salty water; and (2) mussels produce larvae that can disperse long distances before they settle on rocks and grow into adults.

Natural selection changes allele frequencies because some _________ survive and reproduce better than others.

(A) alleles

(B) loci

(C) species

(D) individuals

What is the relative fitness of a sterile mule? Explain.

See all solutions

Recommended explanations on Biology Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free