EvolutionLesson 1 of 4 in the course Evolution and Its Processes

Natural Selection, Population Genetics, and Evolutionary Patterns

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

This lesson traces how ideas about changing species developed before and during the nineteenth century, culminating in Charles Darwin and Alfred Russel Wallace’s explanation of natural selection.

For centuries, influential thinkers treated species as fixed and unchanging. This view was associated with the writings of Plato, although some ancient Greek thinkers expressed ideas resembling evolutionary change. In the eighteenth century, naturalists including Georges-Louis Leclerc, Comte de Buffon, and Erasmus Darwin, Charles Darwin’s grandfather, again considered the possibility that species could change. The recognition that some species had become extinct also challenged the idea that all living forms had always existed unchanged.

All flashcards

Natural selection
A process in which heritable differences in survival or reproduction cause traits to become more or less common across generations.
Geological gradualism
The idea that gradual processes operating over immense periods can produce major geological changes.
Mutation
A change in DNA and the ultimate source of new alleles.
Homologous structures
Structures that share an evolutionary origin, even when their current forms or functions differ.
Sexual selection
Selection based on differences in success at obtaining mates and producing offspring.

Quiz questions

  1. What makes a heritable trait an adaptation?Answer: It improves survival or reproduction in a particular environment.
  2. Which process is the ultimate source of new alleles?Answer: Mutation
  3. Why are bat and insect wings considered analogous structures?Answer: They have similar functions but evolved independently from different ancestral structures.
  4. Under Hardy–Weinberg equilibrium, what effect does dominance alone have on an allele's frequency?Answer: Dominance alone does not cause the allele's frequency to rise.
  5. When can migration between populations change allele frequencies?Answer: When individuals move between populations that differ in allele frequencies.

Based on Concepts of Biology by Samantha Fowler, Rebecca Roush, James Wise (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

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