U3 Terms Flashcards

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1
Q

Recombination

A

Moves mutations around to different copies of a chromosome

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2
Q

Independent Assortment

A

Influences how chromosomes get packaged into gametes

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3
Q

Mutations are the…
and they… (3 things)

A

“Variation factory”

1) Occur randomly
2) Are found in everyone
3) Can be good, bad, or neutral

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4
Q

Production of new variation CANNOT… (2)

A

1) Be stopped
2) Be predicted

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5
Q

Natural Selection

A

Heritable variation being transmitted and sorted differently based on different environments

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6
Q

Components of Natural Selection (3)

A

1) Production (heritable variation)
2) Transmission (heredity)
3) Sorting (survival/reproduction)

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7
Q

Types of Selection

A

1) Stabilizing selection
2) Directional selection
3) Disruptive selection

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8
Q

Stabilizing Selection

A

(Bell curve gets skinnier: removing the variance at both extremes)

–> Variance decreases
–> Mean peak (most common phenotype) stays the same

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9
Q

Directional Selection

A

(Bell curve moves towards one side)

–> Mean value of the character (most common phenotype: the peak) changes

–> Causes the removal of one of the extremes (the one shifting away from)

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10
Q

Disruptive Selection

A

(Bell curve peak is disrupted)

–> Variance increases
–> Extremes increase

–> Medium variants become less common and the extremes become more common

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11
Q

Mutations are…

A

Random

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12
Q

Natural selection is…

A

NON-random

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13
Q

Sexual Dimorphism

A

The systematic difference in form between individuals of different sex within the same species

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14
Q

The environment does NOT ______ mutations

A

cause

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15
Q

Environmental change or the need to adapt CANNOT….

A

Change or force the variation factory to produce different/specific variation

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16
Q

Sexual Selection

A

Explains the patterns in which there is variation between the sexes in a single species

(Why different species have different types of sexual dimorphisms)

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17
Q

How resources are distributed has a major effect on….

A

Sexual Selection

18
Q

Clustered Resources

A

Males can try to control access to resources that females require
–> Leads to more male-male competition

–> Males battle for control of resources and female mates (The “burlier” usually wins)

19
Q

Dispersed Resources

A

Males CANNOT control access to resources (as they are spread out)

–> Males instead try to attract females

–> The fancier a male, the more attractive they can be to females (in most species)

20
Q

Why do only males get “fancy” and females don’t?

A

Because having fancy traits are selected against by natural selection (less camouflage = less survival)

21
Q

Males will get “fancier” and “fancier” until…

A

It begins to seriously affect their survival

22
Q

Natural vs Sexual Selection

A

NATURAL = Leads to adaptations for gathering resources and surviving

SEXUAL = Leads to adaptions for gathering mates and breeding

23
Q

Natural and sexual selection are composed of the same steps. In which step do they differ?

A

SAME = Production and Transmission steps

DIFFERENT = Sorting step

24
Q

Random

A

Lack of pattern or predictability of an event

(No order of clear pattern)

CHANCE

25
Q

Non-Random

A

Presence of a pattern or a predictable event

(There IS order and a pattern)

–> Opposite of chance

26
Q

Genetic Drift

A

(Third sorting process)

Sorting (survival) of individuals/alleles due to CHANCE

–> Random sorting/survival

27
Q

Genetic Drift is NOT:

A

The event causing the sorting (Ex: forest fire)

28
Q

Genetic drift is more common in/for…

A

1) Smallepopulations
2) Rare alleles

29
Q

Bottleneck Effect

A

A sharp reduction in size of population due to an environmental event

–> Reduces variation (as only certain variants survive the event)

30
Q

Founder Effect

A

When a small group of migrants (not genetically representative of the population from which they came) establish in a new area

–> Reduces genetic variation in the newly established population

31
Q

Random Components of Evolution

A

1) Mutation (variation factory)
2) Genetic Drift

32
Q

Non-Random Components of Evolution

A

1) Natural Selection
2) Sexual Selection

33
Q

Species

A

Groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other groups

34
Q

Speciation

A

The evolution of populations to become distinct species

35
Q

What causes speciation?

A

1) Groups becoming separated in space

2) Groups becoming different enough in form or behavior that individuals of one group do not regularly mate with individuals outside the group

36
Q

For species to form…

A

populations must become different enough so they can’t reproduce

37
Q

Reproductive Isolation

A

The prevention of different species producing offspring together

(2 main mechanisms)

38
Q

Main mechanisms of reproductive isolation:

A

1) Pre-Zygotic Isolation

2) Post-Zygotic Isolation

39
Q

Pre-Zygotic Isolation

A

Barrier that occurs BEFORE a zygote can be made

(3 main barriers)

40
Q

Main Pre-Zygotic Isolating Factors:

A

1) Behavioral Isolation
(Ex: different bird songs)

2) Temporal Isolation
(Ex: mating in different seasons)

3) Habitat Isolation
(Ex: terrestrial vs aquatic frogs)

41
Q

Post-Zygotic Isolation

A

Mating and fertilization actually occur producing a zygote BUT some barrier separates the species still

(3 main barriers)

42
Q

Main Post-Zygotic Isolating Factors:

A

1) Infertile Offspring (Sterile)
(Ex: Zonkey)

2) Offspring are weak/sick
(Ex: Don’t survive very long)

3) Genetic Incompatibility = Lack of development (of embryo or beyond)