Speciation - Ch. 14 Flashcards

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1
Q

What’s the difference between microevolution and macroevolution?

A

Microevolution- adaptation of populations

Macroevolution- multiplication of species, generating biological diversity

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2
Q

What is speciation?

A

the divergence of 1 species into 2 or more; the origin of new species

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3
Q

What does the biological species concept state, and what are it’s problems?

A

Populations/organisms belong to the same species if they can: 1. interbreed (mate) and 2. produce fertile offspring in a natural setting.
Problems: Extinct species, asexual species, remote populations
Solutions/other ways to define species: Observable + measurable traits, ecological niches (role in environment), genetic similarities (DNA)

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4
Q

How can populations become different species?

A

Reproductive barriers/Reproduction Isolation prevents individuals of closely related species from interbreeding.

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5
Q

What are the prezygotic barriers? (Prezygotic barriers are barriers that prevent mating or fertilization between species)

A

The prezygotic barriers are:

  1. Temporal Isolation- mating/fertilization occurs at different seasons or times of day
  2. Habitat Isolation- populations live in different habitats and do not meet
  3. Behavioral Isolation- little to no sexual attraction exists between populations; change in behavior reproductively isolates them
  4. Mechanical Isolation- structural/morphological differences prevent fertilization
  5. Gametic Isolation- female and male gametes fail to unite in fertilization; they are incompatible
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6
Q

What are the postzygotic barriers? (Postzygotic barriers are barriers that operate if interspecies mating actually occurs and results in HYBRID zygotes)

A
  1. Reduced Hybrid Viability- hybrids fail to develop or reach sexual maturity
  2. Reduced Hybrid Fertility- hybrids fail to produce functional gametes
  3. Hybrid Breakdown- hybrids are sterile
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7
Q

What are the 2 mechanisms of speciation?

A
  1. Allopatric- geographic barrier physically separates populations; gene flow is blocked
  2. Sympatric- takes place within habitat or parent species; reproductive barrier forms within a subset of population
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8
Q

What’s a polyploid?

A

Accidents during cell division results in an extra set of chromosomes (polyploid).

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