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

Introduction to Speciation

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1:34 minutes

Problem 5

Textbook Question

Which of the following factors would be the most likely to contribute to allopatric speciation?
a. The separated population is large, and genetic drift occurs.
b. Selection pressures in the isolated population are similar to those in the ancestral population.
c. Gene flow between the two populations is extensive.
d. Different mutations begin to distinguish the gene pools of the separated populations.

Verified step by step guidance

Understand the concept of allopatric speciation: Allopatric speciation occurs when populations of the same species become geographically isolated, preventing gene flow between them. Over time, genetic differences accumulate, leading to the formation of new species.

Analyze the role of genetic drift: Genetic drift is more likely to have a significant impact in small populations rather than large ones. Therefore, option A is less likely to contribute to allopatric speciation in this scenario.

Evaluate the impact of selection pressures: If selection pressures in the isolated population are similar to those in the ancestral population, there is less likelihood of divergence. Thus, option B does not strongly support allopatric speciation.

Consider the effect of gene flow: Extensive gene flow between populations would counteract the genetic divergence necessary for speciation. Therefore, option C is unlikely to contribute to allopatric speciation.

Examine the role of mutations: Mutations introduce genetic variation, and if different mutations accumulate in the isolated populations, they can lead to divergence in the gene pools. This process is a key factor in allopatric speciation, making option D the most likely contributor.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Allopatric Speciation

Allopatric speciation occurs when a population is geographically separated, leading to reproductive isolation. This separation can result from physical barriers like mountains or rivers, preventing gene flow between the groups. Over time, the isolated populations may evolve independently, potentially leading to the emergence of new species.

Genetic Drift

Genetic drift is a mechanism of evolution that involves random changes in allele frequencies within a population. It is particularly significant in small populations, where chance events can lead to the loss or fixation of alleles. This can contribute to divergence between separated populations, enhancing the likelihood of speciation.

Gene Flow

Gene flow refers to the transfer of genetic material between populations through migration and interbreeding. High levels of gene flow can counteract the effects of speciation by homogenizing genetic differences. In the context of allopatric speciation, reduced gene flow is crucial, as it allows populations to diverge genetically and adapt to their unique environments.

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Can factors that cause sympatric speciation also cause allopatric speciation? Explain.

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Multiple Choice

Which of the following is an example of temporal isolation in speciation?

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Multiple Choice

Which of the following must occur for speciation to happen?