Population genetics and speciation Flashcards

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1
Q

What is a population?

A

A group of same species living in a specific environment/area

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2
Q

Microevolution

A

The change in allelic frequencies in a population over time

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3
Q

Genetic variation

A

Phenotypic variation based on changes in genes/DNA sequences

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4
Q

A single globin gene underwent____and_______. Mutations resulted in __________?

A

Duplication and divergence

Two different functioning genes on two different chromosomes

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5
Q

What are fixed alleles?

A

When there is only one allele for a particular locus

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6
Q

What is the Hardy-Weinberg Equilibrium?

A

In a population that is not evolving, allele and genotype frequencies remain constant from one generation to another

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7
Q

What equation is for allelic frequencies?

A

1 = p + q

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8
Q

What equation is for genotypic frequencies?

A

p^2 + 2pq + q^2 = 1

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9
Q

What are the assumptions of Hardy-Weinberg?

A
  1. No mutations
  2. Random mating
  3. No natural selection
  4. Large population
  5. Isolated population
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10
Q

What is genetic drift?

A

Change in allelic frequencies in a small population

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11
Q

What is the bottleneck effect?

A

Catastrophic event, a large number of individuals die, the allele frequency in the new population changes drastically. Usually reduces allele variability

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12
Q

What is the founder effect?

A

When a group of individuals move to a new area and form a new population, without the original population dying

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13
Q

Genetic drift is significant in______?

A

Small populations

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14
Q

Genetic drift can lead to______?

A

A loss of genetic variation within populations

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14
Q

Genetic drift can cause allelic frequencies to_______?

A

Change at random

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15
Q

Genetic drift can cause harmful alleles to become______?

A

Fixed

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16
Q

Gene flow

A

Immigration or emigration of population

17
Q

Does immigration and emigration increase or reduce genetic differences?

A

Reduce. Alleles are exchanged

18
Q

Natural selection

A

If an allele is favourable, the frequency of that allele goes up in a population. If it is harmful, the frequency goes down.

19
Q

The role of natural selection in the gradual adaptation of a population to its environment is an example of what kind of evolution?

A

Microevolution

20
Q

What is the broad pattern of evolution above the species level?

A

Macroevolution

21
Q

Why doesn’t the first species definition work?

A

Hybrids exist (when two species mate)

They are usually infertile and don’t survive

ex. Mules, Grolar bears, coywolf

21
Q

Species definition 1: Biological species concept

A species is_____.

Formation of new species depends on_____?

A

A group of populations whose members can interbreed and produce fertile offspring

Reproductive isolation (no gene flow)

22
Q

Species definition 2: Morphological species concept

Classification based upon______.

A

Physical traits like size, shape, etc.

22
Q

Why doesn’t the second definition of species work?

A

Can lead to false clasification

Chihuahuas and Great Danes don’t look alike, but they are the same species

23
Q

Species definition 3: Ecological species concept

View species in terms of______.

What type of selection can it lead to?

A

Its ecological niche, and how the population interacts with the non-living and living things in its environment

Ex. Oak trees. One can tolerate the dry, the other cannot

Disruptive selection

24
Q

For two species to be separate, a mechanism must be in place that keeps them from breeding called?

A

Reproductive barriers

25
Q

What are the two types of reproductive barriers?

A

Prezygotic barriers
Postzygotic barriers

26
Q

What are the types of prezygotic barriers?

A

Habitat isolation: Two species in the same environment, but separate habitats so they don’t interact

Temporal isolation: Breeding at different times or seasons

Behavioural isolation: Different courtship rituals

Mechanical isolation: Physical incompatibility of reproductive parts

Gametic isolation: Molecular incompatibility of eggs and sperm

27
Q

What are the types of postzygotic barriers?

A

Reduced hybrid viability: hybrids cannot fully develop or are unable to reproduce due to the interaction of parental genes

Reduced hybrid fertility: Healthy hybrids that cannot produce offspring

Hybrid breakdown: The first generation is viable, but the second is not

28
Q

What is allopatric speciation?

A

When a population is divided into geographically isolated populations due to changes in geography or waterbodies

29
Q

What does allopatric speciation lead to?

A

Founder effect
Genetic drift
Natural selection

30
Q

What is sympatric speciation?

A

When a population is divided without geographic isolation

31
Q

How does sympatric speciation arise?

A

Polyploidy, habitat differentiation (water temperature), sexual selection

32
Q

Polyploidy

A

Cells that contain more than two paired chromosomes

33
Q

Autoploidy

A

Doubling of chromosomes in the same species

34
Q

Allopolyploidy

A

Hybridization of two different species, followed by cell division

35
Q

What plant created in Manitoba was caused by allopolyploidy?

A

Canola

36
Q

Habitat differentiation

A

When a subpopulation starts to use a habitat or resource not used by its parents

37
Q

Can sexual selection occur both allopatrically and sympatrically? How?

A

Yes
Allopatric: separated populations develop new mating behaviours and if they are re-introduced, will not interbreed

Sympatric: changing mating behaviours in the same habitat will lead to restrictions in gene flow