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Ecology & Evolution > Unit 3 Lecture 13 > Flashcards

Unit 3 Lecture 13 Flashcards

1
Q

Explain the study of the Red-Collared Widowbird

A
  • measured tail of each male
  • measured body condition
  • experimentally shortened some tails
  • Figured out how many mates they had
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2
Q

Explain the female choice

A
  • Females who choose males with attractive traits pass alleles to their offspring that influence expression of the trait and the preference
  • Leads to stronger preferences and larger display traits
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3
Q

What is sexual cannibalism?

A

In red-backed spiders, males voluntarily get eaten

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4
Q

What are conditions under which males might be selected to be eaten by the female (i.e. benefit from copulatory suicide)

A
  • Males rarely have a chance to mate more than once in the wild (80% die before mating)
  • But females can mate more than once
  • Females that ate a male often refused mating with another male
  • Males that were eaten got to copulate 2x as long (transfer sperm while being eaten) and had 2x more offspring
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5
Q

Explain the study of the Oldfield Mouse and Beach Mouse with evolution

A

Studiers wanted to know if white coat color evolved once or many times in mice; and the underlying genetic mechanism
- They found out that white coat color evolved many times, and the underlying genetics mechanism is different in the gulf coast mice compared to Atlantic coast mice

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6
Q

Are they different species?
Polar Bears vs. Grizzly Bears
- Different color
- Genetic Analysis suggests started diverging 500,000 years ago
- Continued to hybridize for a long time
- They share a lot of genes
- Hybrids are viable and fertile

A

Same Species

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7
Q

Are they different species?
Eastern Meadowlard vs. Western Meadowlard
- Morphologically indistinguishable but songs sound different
- Range overlaps in some places, but rarely interbreed
- Genetic divergence started 2.5 million years ago
- Hybrids are sterile

A

Different species

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8
Q

Are they different species?
Drosophila Simulans vs. D. Mauritiana
- Morphologically different in some traits
- Range does not overlap
- Diverged 250,000 years ago
- Can produce hybrids but offspring are sterile

A

Two diff. species

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9
Q

Are they different species?
Hawthorne Fly found on plant vs. apple
- Morphologically very similar
- Lives in same places when hawthorns and apples grow close by but mates and reproduced on different host plants
- Host plants mature at slightly different times
- Started diverging in the past 400 years
- Hybrids are produced rarely in nature and are viable and fertile

A

Two diff. Species

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10
Q

Are they different species?
Corals Monostrea Annularis vs. M. Franksi
- Morphologically different in some locations very similar in others
- Ranges overlap, but spawns at different times of the day
- Diverged 500,000 years ago
- In some locations genetically different but in other locations genetically indistinguishable
- Hybrids are viable and fertile

A

Single Species

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11
Q

Are they different species?
Elk Deer vs. Red Deer
- Morphologically very similar, biggest difference is in vocalization
- Ranges do not overlap
- Genetically different lineage, diverged 9,000 years ago
- Can interbreed in captivity; hybrids are viable and fertile

A

Single species

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12
Q

Are they different species?
Red Fox vs. Gray Fox
- Superficially similar but many differences
- Ranges overlap in North America
- Diverged 10 million years ago
- Not known to hybridize

A

Two dif. Species

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13
Q

Are they different species?
Common Redpoll vs. Hoary Redpoll
- Plumage differences
- Ranges overlap a lot
- Cannot distinguish them genetically
- Hybrids viable and fertile

A

Single Species

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14
Q

What are Species Concept ?

A
  1. Morphological Species concept
  2. Phylogenetic Species concept
  3. Biological Species concept
  4. General Lineage species Concept
    - Each concept has pros and cons and gray areas
    - Concepts generally agree that species in some unit of biological organization that evolves together
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15
Q

What is morphological concept?

A

Differences need to be great enough that we would clearly identify them as different species

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16
Q

What Is phylogenetic concept?

A

Concept basically says that we need to use a phylogeny and genetic differentiation. Once we reach/get a certain percentage genetic differentiation, they’re different species, and whether they look the same or not

17
Q

What is biological concept?

A

In which if the species can interbreed, then they are NOT a different species (viable offspring)

18
Q

What is general lineage concept?

A

Uses a phylogeny but does not depend on x percentage of genetic diversion

19
Q

What is species?

A

Think of species as the end point of the process of population divergence

20
Q

Divergence is primarily about the reduction of what?

A

Gene flow
- As long as there is gene flow amongst two populations, there will NOT be divergence in the two populations and they will remain the same species
- However, if gene flow STOPS then there could be different selective pressures none population over the other

21
Q

Speciation primarily involves _____ to reproduction (gene flow)

A

Barriers
- these cause populations to diverge into two groups of different population and will behave as two different evolutionary lineages
- once this happens, evolution can proceed separately and the lineages can differentiate (many types of barriers)

22
Q

Name types of barriers to reproduction

A
  • Geographic barriers
  • Can’t attract
  • Can’t physically mate
  • Adaptation to different environments
  • Sperm can’t fertilize egg
  • Hybrids can’t grow to maturity
  • Hybrids are sterile
  • Hybrids are selected against
23
Q

What does allopatry mean?

A

Populations are separated in space
- Elk and red deer are allopatric because the ocean separates them

24
Q

What does sympatric mean?

A

populations with areas of overlap
- polar bear and grizzly bear

25
Q

Name the 3 steps to allopatric speciation

A
  1. First you have a happy population living together, then a geographic barriers arises and reduces gene flow between the populations
  2. Genetic differences accumulate in each population (divergence) and reproductive barriers evolve (reproductive isolation between 2 population)
  3. By the time geographic barrier goes away (or individuals evolve ability to disperse across barrier) the two populations are NO LONGER able to hybridize
26
Q

Give an example of how geographic barriers can come and go

A
  1. The Bering Strait
  2. Isthmus of Panama
    - Used to be that lobsters could intermix on either side of the Panama, then the Panama closes and there was divergence in population on other side
27
Q

If a population ARE reproductively isolated then….

A

They will remain as separated lineages (i.e. biological species) and won’t be able to interbreed again

28
Q

If a population are NOT reproductively isolated then…

A

They will collapse back together, there will be gene flow amongst the populations again

Ecology & Evolution (26 decks)

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