U3 Terms

Question 1

Recombination

Answer 1

Moves mutations around to different copies of a chromosome

Question 2

Independent Assortment

Answer 2

Influences how chromosomes get packaged into gametes

Question 3

Mutations are the…
and they… (3 things)

Answer 3

“Variation factory”

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

Question 4

Production of new variation CANNOT… (2)

Answer 4

1) Be stopped
2) Be predicted

Question 5

Natural Selection

Answer 5

Heritable variation being transmitted and sorted differently based on different environments

Question 6

Components of Natural Selection (3)

Answer 6

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

Question 7

Types of Selection

Answer 7

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

Question 8

Stabilizing Selection

Answer 8

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

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

Question 9

Directional Selection

Answer 9

(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)

Question 10

Disruptive Selection

Answer 10

(Bell curve peak is disrupted)

–> Variance increases
–> Extremes increase

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

Question 11

Mutations are…

Answer 11

Random

Question 12

Natural selection is…

Answer 12

NON-random

Question 13

Sexual Dimorphism

Answer 13

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

Question 14

The environment does NOT ______ mutations

Answer 14

cause

Question 15

Environmental change or the need to adapt CANNOT….

Answer 15

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

Question 16

Sexual Selection

Answer 16

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

(Why different species have different types of sexual dimorphisms)

Question 17

How resources are distributed has a major effect on….

Answer 17

Sexual Selection

Question 18

Clustered Resources

Answer 18

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)

Question 19

Dispersed Resources

Answer 19

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)

Question 20

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

Answer 20

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

Question 21

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

Answer 21

It begins to seriously affect their survival

Question 22

Natural vs Sexual Selection

Answer 22

NATURAL = Leads to adaptations for gathering resources and surviving

SEXUAL = Leads to adaptions for gathering mates and breeding

Question 23

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

Answer 23

SAME = Production and Transmission steps

DIFFERENT = Sorting step

Question 24

Random

Answer 24

Lack of pattern or predictability of an event

(No order of clear pattern)

CHANCE

Question 25

Non-Random

Answer 25

Presence of a pattern or a predictable event

(There IS order and a pattern)

–> Opposite of chance

Question 26

Genetic Drift

Answer 26

(Third sorting process)

Sorting (survival) of individuals/alleles due to CHANCE

–> Random sorting/survival

Question 27

Genetic Drift is NOT:

Answer 27

The event causing the sorting (Ex: forest fire)

Question 28

Genetic drift is more common in/for…

Answer 28

1) Smallepopulations
2) Rare alleles

Question 29

Bottleneck Effect

Answer 29

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

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

Question 30

Founder Effect

Answer 30

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

Question 31

Random Components of Evolution

Answer 31

1) Mutation (variation factory)
2) Genetic Drift

Question 32

Non-Random Components of Evolution

Answer 32

1) Natural Selection
2) Sexual Selection

Question 33

Species

Answer 33

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

Question 34

Speciation

Answer 34

The evolution of populations to become distinct species

Question 35

What causes speciation?

Answer 35

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

Question 36

For species to form…

Answer 36

populations must become different enough so they can’t reproduce

Question 37

Reproductive Isolation

Answer 37

The prevention of different species producing offspring together

(2 main mechanisms)

Question 38

Main mechanisms of reproductive isolation:

Answer 38

1) Pre-Zygotic Isolation

2) Post-Zygotic Isolation

Question 39

Pre-Zygotic Isolation

Answer 39

Barrier that occurs BEFORE a zygote can be made

(3 main barriers)

Question 40

Main Pre-Zygotic Isolating Factors:

Answer 40

1) Behavioral Isolation
(Ex: different bird songs)

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

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

Question 41

Post-Zygotic Isolation

Answer 41

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

(3 main barriers)

Question 42

Main Post-Zygotic Isolating Factors:

Answer 42

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)