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Biol 1620 > Ch 2 > Flashcards

Ch 2 Flashcards

1
Q

What are the different Species Concepts?

A

Morphological SC
Biological SC
Ecological SC
Phylogenetic SC

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2
Q

What is the morphological SC based on?

A

visual similarities

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3
Q

What is the biological SC based on?

A

based on reproduction / gene flow within a population

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4
Q

According to the biological SC, members of a different species do not interbreed because of pre-zygotic and post-zygotic “blocks.
What are the pre-zygotic blocks?

A 
Mechanical Isolation
Behavioral Isolation
Temporal
Ecological Isolation
Gametic Isolation
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5
Q

What is mechanical isolation?

A

populations are structurally unable to reproduce

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6
Q

What is behavior isolation?

A

individuals don’t recognize mating rituals from other poulations

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7
Q

What is temporal isolation?

A

individuals have different mating times (day, year, age)

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8
Q

What is ecological isolation?

A

individuals have different mating locations

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9
Q

What is gametic isolation?

A

different chemical signals of gametes (do not fuse; are syngamy)

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10
Q

According to the biological SC, members of a different species do not interbreed because of pre-zygotic and post-zygotic “blocks.”
What are the post-zygotic blocks?

A

hybrid inviability

hybrid sterility

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11
Q

What is hybrid inviability?

A

zygote does not develop (death before development)

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12
Q

What is hybrid sterility?

A

hybrids are sterile

no gene flow between populations

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13
Q

What is the ecological SC?

A

otherwise similar organisms/groups may be distinguished by niche preference within a variable environment

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14
Q

What is the phylogenetic SC?

A

populations can be traced to a common ancestor that has evolved significantly different differences in diagnostic traits

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15
Q

How do new species form?

A

Speciation

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16
Q

What does speciation involve?

A
  • reproduction isolation of 2 or more populations of an ancestral species
  • genetic divergence of the isolated populations
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17
Q

What are the different types of speciation?

A

Allopatric speciation

sympatric speciation

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18
Q

What is allopatric speciation?

A

when formerly isolated population re-converges with and is no longer able to reproduce with ancestral population

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19
Q

Steps to allopatric speciation

A
  • geographic isolation of 2+ populations from an ancestral species
  • genetic divergence (mutations)
  • reproductive isolating mechanism is evolved
  • new species
20
Q

What is Sympatrick Speciation?

A

A mutation occurs within the ancestral population

21
Q

Steps to Sympatric Speciation

A

Ancestral population

  • isolated mechanism is formed within population
  • genetic divergence occurs
  • new species
22
Q

What are 2 changes that support Sympatric Speciation?

A

Ploidy Changes

Changes in Ecological Factors

23
Q

What are Ploidy Changes

A

Part of Sympatric Speciation

- polyploidy: 3+ complete sets of chromosomes

24
Q

What types of Ploidy Changes are there?

A

Autopolyploidy

Allopolyploidy

25
Q

What is Autopolyploidy?

A

Polyploid is formed by non disjunction during meiosis

26
Q

Is autopolyploidy more common or less common to allopolyploidy?

A

Less common

27
Q

What is Allopolyploidy?

A

Closely related but differing species produce hybrid

  • hybrid doubles the # of chromosomes through non disjunction
  • results in allopolyploidy
  • generic divergence occurs
  • new species
28
Q

What are Changes in ecological speciation?

A

Part of Sympatric Speciation

  • simple mutation producing a change in niche preference / mating behavior
  • this disrupts selection
29
Q

What is adaptive radiation?

A

When 1 species grows into many more

30
Q

What is character displacement?

A

When 2 similar, isolated species come together

They will have to compete not only within species, but with the new species as well

This causes each species average characteristics to move toward the extremes

31
Q

What happens at the hybrid zone between closely related species?

A

Fusion

Reinforcement

Stability

32
Q

What is fusion in the hybrid zone?

A

Gene flow occurs into both populations

-this merges the gene pools

33
Q

What happens during reinforcement in the hybrid zones?

A

Hybrids are less successful in producing offspring

-this strengthens reproductive isolating factors over time

34
Q

What is stability in the hybrid zones?

A

Hybrids are formed

-no significant fusion or reinforcement occurs

35
Q

What is Phyletic Gradualism?

A

Steady change within a lineage

-older theory

36
Q

What is Punctuated Equilibrium?

A 
Rapid Speciation (a Speciation event)
-followed by stability (stasis)
37
Q

When was the earth formed?

A

4.5b yrs ago

38
Q

When were the oldest fossils found

A

3.5b yrs ago

39
Q

When did the banded iron formations occur?

A

2.2-2.8b yrs ago

40
Q

What was the significance of the banded iron formations?

A

Pointed to massive amounts of free oxygen in the air

  • likely causes by photosynthesis
  • resulted in iron being oxidized and precipitating
41
Q

When was the oldest eukaryotes fossils dated to?

A

2.1b yrs ago

42
Q

When we’re the oldest tetrads dated to?

A

1.1b yrs ago

43
Q

What’s the significance of tetrads?

A

Sexual reproduction

44
Q

What’s the earliest multicellular animal fossil?

A

600m yrs ago

45
Q

When’s the earliest plant?

A

425m yrs ago

46
Q

When is the modern homo sapien dated?

A

30-50k yrs ago

Biol 1620 (22 decks)

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