Table of contents

1. Introduction to Biology2h 42m
2. Chemistry3h 37m
3. Water1h 26m
4. Biomolecules2h 23m
5. Cell Components2h 26m
6. The Membrane2h 31m
7. Energy and Metabolism2h 0m
8. Respiration2h 40m
9. Photosynthesis2h 49m
10. Cell Signaling59m
11. Cell Division2h 47m
12. Meiosis2h 0m
13. Mendelian Genetics4h 44m
14. DNA Synthesis2h 27m
15. Gene Expression3h 6m
16. Regulation of Expression3h 31m
17. Viruses37m
- Viruses
  37m
18. Biotechnology2h 58m
19. Genomics17m
- Genomes
  17m
20. Development1h 5m
21. Evolution3h 1m
22. Evolution of Populations3h 53m
23. Speciation1h 37m
24. History of Life on Earth2h 6m
25. Phylogeny2h 31m
26. Prokaryotes4h 59m
27. Protists1h 12m
28. Plants1h 22m
29. Fungi36m
- Fungi
  19m
- Fungi Reproduction
  17m
30. Overview of Animals34m
- Overview of Animals
  34m
31. Invertebrates1h 2m
32. Vertebrates50m
33. Plant Anatomy1h 3m
34. Vascular Plant Transport1h 2m
- Water Potential
  1h 2m
35. Soil37m
- Soil and Nutrients
  20m
- Nitrogen Fixation
  16m
36. Plant Reproduction47m
- Flowers
  33m
- Seeds
  14m
37. Plant Sensation and Response1h 9m
38. Animal Form and Function1h 19m
39. Digestive System1h 10m
- Digestion
  1h 3m
- Blood Sugar Homeostasis
  7m
40. Circulatory System1h 49m
41. Immune System1h 12m
42. Osmoregulation and Excretion50m
- Osmoregulation and Excretion
  50m
43. Endocrine System1h 4m
- Endocrine System
  1h 4m
44. Animal Reproduction1h 2m
- Animal Reproduction
  1h 2m
45. Nervous System1h 55m
- Neurons and Action Potentials
  1h 8m
- Central and Peripheral Nervous System
  46m
46. Sensory Systems46m
- Sensory System
  46m
47. Muscle Systems23m
- Musculoskeletal System
  23m
48. Ecology3h 11m
49. Animal Behavior28m
- Animal Behavior
  28m
50. Population Ecology3h 41m
51. Community Ecology2h 46m
52. Ecosystems2h 36m
53. Conservation Biology24m
- Conservation Biology
  24m

1. Introduction to Biology

Natural Selection and Evolution

General Biology

1. Introduction to Biology

Natural Selection and Evolution

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Multiple Choice

Which of the following scenarios is best explained by natural selection rather than other evolutionary mechanisms?

Genes are exchanged between two populations of flowers when pollen is carried by the wind.

A hurricane randomly kills a large portion of a coastal lizard population, leaving only a few survivors.

A population of moths becomes darker over generations because darker moths are less likely to be eaten by predators.

A small group of birds migrates to a new island and establishes a new population with different allele frequencies.

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Verified step by step guidance

Step 1: Understand the concept of natural selection. Natural selection is a mechanism of evolution where individuals with traits that provide a survival or reproductive advantage are more likely to pass on their genes to the next generation. Over time, this leads to an increase in the frequency of advantageous traits in the population.

Step 2: Analyze the first scenario: 'Genes are exchanged between two populations of flowers when pollen is carried by the wind.' This describes gene flow, which is the transfer of genetic material between populations. It is not an example of natural selection because it does not involve differential survival or reproduction based on traits.

Step 3: Analyze the second scenario: 'A hurricane randomly kills a large portion of a coastal lizard population, leaving only a few survivors.' This describes genetic drift, a random change in allele frequencies due to chance events. It is not an example of natural selection because the survival of individuals is not based on advantageous traits.

Step 4: Analyze the third scenario: 'A population of moths becomes darker over generations because darker moths are less likely to be eaten by predators.' This is an example of natural selection because the darker coloration provides a survival advantage (camouflage from predators), leading to an increase in the frequency of the darker trait over generations.

Step 5: Analyze the fourth scenario: 'A small group of birds migrates to a new island and establishes a new population with different allele frequencies.' This describes the founder effect, a type of genetic drift that occurs when a new population is established by a small group of individuals. It is not an example of natural selection because the allele frequencies change due to the small population size, not due to advantageous traits.