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

23. Speciation

Introduction to Speciation

General Biology

23. Speciation

Species

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Multiple Choice

Which of the following is an example of a postzygotic reproductive barrier?

One species of frog mates in April, but another mates in May.

The sperm of a marine worm can only fertilize eggs of the same species.

One species of flower grows in forested areas, another in meadows.

Two pheasant species perform different courtship dances.

Two fruit flies of different species produce sterile offspring.

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Verified step by step guidance

Understand the concept of reproductive barriers: Reproductive barriers are mechanisms that prevent species from mating with each other or ensure that any offspring are sterile. They are divided into prezygotic and postzygotic barriers.

Identify prezygotic barriers: These occur before fertilization and include temporal isolation (mating at different times), habitat isolation (living in different environments), behavioral isolation (different mating rituals), and mechanical or gametic isolation (incompatibility of reproductive organs or gametes).

Identify postzygotic barriers: These occur after fertilization and include hybrid inviability (offspring do not develop properly), hybrid sterility (offspring are sterile), and hybrid breakdown (offspring are fertile but their descendants are not).

Analyze the given options: The first four options describe prezygotic barriers: temporal isolation (frogs mating in different months), gametic isolation (marine worm sperm), habitat isolation (flowers in different areas), and behavioral isolation (pheasants with different dances).

Recognize the correct example of a postzygotic barrier: The last option, 'Two fruit flies of different species produce sterile offspring,' describes hybrid sterility, a postzygotic barrier, because the offspring are unable to reproduce.