wunder beta

📘 How does natural selection change a population?

Imagine two islands with related finches. If one island offers hard seeds and the other offers soft seeds, inherited beak differences can change which birds leave descendants.

5
lessons
~25 min
to learn
Adults
level
Start the course →

What you’ll learn

  1. Variation supplies the raw materialIdentify heritable variation and explain why it is required for selection to change descendants.Mutation and reproduction supply inherited differences that selection can filter.
  2. Differential survival and reproductionExplain fitness as relative reproductive success and connect environmental pressures to unequal outcomes.Predators, mates, and antibiotics can change which variants leave descendants.
  3. Population frequencies changeDescribe how selection changes allele frequencies or trait distributions without transforming individuals.Repeated unequal reproduction shifts the composition of a population.
  4. Evidence across measurable timescalesUse generation time and replicated measurements to evaluate evolutionary change.Fast-reproducing organisms make population change measurable over short calendar times.
  5. What selection can and cannot explainDistinguish selection from other evolutionary forces and state why fitness is context dependent.Selection creates conditional adaptations, not perfect or universal organisms.

Questions this course answers

Which variation can natural selection change across generations?

Selection can shift inherited variants because descendants can receive them.

Put the natural selection pathway in order.

Variation comes first, differential reproductive success follows, and the population composition changes in descendants.

What does biological fitness measure?

Fitness is reproductive success relative to others in the same setting.

Match each term to its role.

Several mechanisms can change population genetics, and they should not be confused.

What changed in a population of dark and light moths when dark moths left more offspring?

Natural selection changes descendant proportions rather than transforming individuals.

Why can antibiotic treatment increase the proportion of resistant bacteria?

The antibiotic filters the population; it does not make every bacterium deliberately adapt.

Grounded in trusted sources

  • OpenStax, Concepts of Biology, 11.1 Discovering How Populations Change, https://openstax.org/books/concepts-biology/pages/11-1-discovering-how-populations-change
  • OpenStax, Biology 2e, 19.3 Adaptive Evolution, https://openstax.org/books/biology-2e/pages/19-3-adaptive-evolution
  • Centers for Disease Control and Prevention, About Antimicrobial Resistance, https://www.cdc.gov/antimicrobial-resistance/about/index.html
  • Natural History Museum, Rainbow nature: life in black and white, https://www.nhm.ac.uk/discover/rainbow-nature-life-in-black-and-white.html
  • Lenski Research Group, Long-Term Evolution Experiment, https://myweb.uiowa.edu/pbrehm/
  • Wikimedia Commons MediaWiki API, image metadata and thumbnails, https://commons.wikimedia.org/w/api.php

Every Wunder lesson is built from real, reputable sources — never invented.

Related courses

📘How does a mountain range rise?📘How does a hydroelectric dam generate power?📘How do electric eels make electricity?📘Why does your stomach growl?📘What are Saturn’s rings made of?📘What is fog?📘How old is the universe?📘How do broken bones heal?

Wunder is a personalized learn-anything platform — tell it any topic and it builds a beautiful, fact-checked course in minutes, with narration, a knowledge check, and a college-style University track.

All topics · Home

© 2026 Wunder Learning LLC · Terms & Privacy