Natural Selection

About this deck

This deck includes 36 flashcards covering natural selection, darwin, variation, and related concepts. Use it to review key Biology ideas, focus on weak cards, and prepare for your exam with StudyLess.

1. 01

   What was the title and publication year of Darwin's most famous work?

   On the Origin of Species (1859).

2. 02

   What is Fitness?

   An organism's ability to survive and reproduce in its environment.

3. 03

   Does natural selection act on phenotype or genotype?

   Phenotype, as it acts on observable physical traits/behavior.

4. 04

   What are the five Hardy-Weinberg conditions?

   No mutations, no gene flow, large population, random mating, no natural selection.

5. 05

   What is the connection between variation, natural selection, and evolution?

   Variation provides traits → natural selection favors helpful ones → traits become more common = evolution.

6. 06

   What are selection pressures and what are some examples?

   Factors affecting survival; e.g., predators, disease, food availability.

7. 07

   What's the difference between a population and a species?

   Population: same species, same area. Species: organisms that can interbreed and produce fertile offspring.

8. 08

   What did Grant's finch experiment demonstrate about natural selection?

   During drought, large-beaked finches survived better due to large seeds, increasing average beak size.

9. 09

   What's the difference between the bottleneck effect and the founder effect?

   Bottleneck: population drastically reduced by disaster. Founder: small group splits off to start new population.

10. 10

    What's the difference between single gene and polygenic traits in terms of selection?

    Single gene: few distinct phenotypes, selection picks one. Polygenic: range of phenotypes, selection shifts/narrows curve.

11. 11

    Who were the key influences on Darwin and what were their main ideas?

    Lyell (Earth changes slowly), Malthus (populations compete), Lamarck (organisms change over time).

12. 12

    What is Natural Selection?

    Individuals with better-suited traits survive and reproduce more, passing those traits on.

13. 13

    What are gene pools and allele frequencies, and how do they relate to evolution?

    Gene pool is all alleles in a population; allele frequency is how common each is. Evolution is change in frequencies.

14. 14

    What is genetic drift?

    Random changes in allele frequencies, mostly affecting small populations.

15. 15

    What are the three mechanisms of genetic variation?

    Mutation, sexual recombination, gene flow.

16. 16

    What are the three principles of Natural Selection?

    Variation exists, traits are heritable, favorable traits lead to more reproduction.

17. 17

    What is directional selection?

    Favors one extreme, causing the population to shift in that direction.

18. 18

    What is disruptive selection?

    Favors both extremes, selects against the middle, causing population to split.

19. 19

    What is stabilizing selection?

    Favors the average, selects against extremes, leading to less variation.

20. 20

    What is speciation?

    When one species splits into two or more new species.

21. 21

    What are four ways reproductive isolation develops?

    Geographic, behavioral, temporal, and mechanical/gametic isolation.

22. 22

    How did speciation occur in the Galápagos finches?

    Ancestor species arrived, adapted different beaks to island food, leading to 13 separate species.

23. 23

    What's the difference between microevolution and macroevolution?

    Micro: small allele frequency changes within a population. Macro: large-scale change over time, produces new species.

24. 24

    What's the difference between divergent and convergent evolution?

    Divergent: related species become different. Convergent: unrelated species become similar.

25. 25

    Why did Darwin hesitate to publish his ideas?

    His ideas contradicted religious beliefs; he spent ~20 years collecting evidence before publishing.

26. 26

    What's the difference between homologous and analogous structures, and how do they relate to divergent/convergent evolution?

    Divergent → Homologous (same structure, different function). Convergent → Analogous (different structure, same function).

27. 27

    How do coevolution and macroevolution relate?

    Two species pressure each other to change over time, leading to large enough changes to produce new species.

28. 28

    What are vestigial structures and what are some examples?

    Body parts that lost their function over evolution; e.g., human tailbone, whale hip bones.

29. 29

    Why does marsupial distribution matter for evolution?

    Marsupials in Australia and South America support common ancestry and evolution due to past continent connection.

30. 30

    What does the fossil record show about evolution?

    Shows how species changed over time, transitional forms, and life's long history of change.

31. 31

    How does molecular biology support evolution?

    Closely related species share more similar DNA; more alike genes mean more recent common ancestor.

32. 32

    What is artificial selection and why did Darwin use it as proof?

    Humans breed organisms for desired traits. Darwin used it to show selective pressure changes traits naturally.

33. 33

    What is the role of extinction in evolution?

    Removes species, opens niches, allowing other species to evolve and diversify to fill them.

34. 34

    What were Darwin's key observations about species?

    Species varied between islands, fossils resembled nearby living species, and isolated populations looked different.

35. 35

    What are the Hardy-Weinberg equations and what do the variables represent?

    p² + 2pq + q² = 1 and p + q = 1. p=dominant allele, q=recessive allele, p²=homozygous dominant, q²=homozygous recessive, 2pq=heterozygous.

36. 36

    What is reproductive isolation?

    When two populations can no longer interbreed and produce fertile offspring.