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Flashcards in Friday Quiz Deck (37)
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1

Variation leads to

Natural selection

2

Morfitt phenotypes produced more ____

Offspring

3

What is allele frequency

Number of times an allele appears in a gene pool
Has nothing to do with whether an allele is dominant or recessive

4

What involves changes in allele frequency in a gene pool overtime

Evolution

5

Population does evolve true or false

True

6

Individuals do evolve true or false

False

7

Natural selection affects

Individuals

8

Survival/death effects

The whole population

9

What are the sources of variation

Mutations
Sexual recombination (meiosis)
Lateral gene transfer (bacteria use pili to pick up new genes)

10

How does natural selection affect phenotype

Natural selection on single gene traits--->allele frequency changes--->changes in phenotype

11

How does natural selection affect more than one gene trait

Natural selection on polygenetic trait affect the fitness levels of various phenotypes which leads to three possible types of selection

12

What is directional selection

Where individuals of one extreme have a higher fitness than those in the middle or other extreme

13

What is stabilizing selection

Where individuals in the middle have a higher fitness than either of the extremes

14

What is disruptive selection

Where individuals at both extremes have a higher fitness than those in the middle

15

What is speciation

Making new species

16

What is a species

Organisms that are able to reproduce and produce fertile offspring

17

What events caused the formation of a new species

Genetic changes
Environmental pressure
Biotic and abiotic factors
Isolating mechanisms

18

Define isolating mechanisms

Events that cause organisms to become reproductively isolated Drive the evolution of new species

19

Behavioral isolation

Depends on mating rituals that allow them to vary from other species. Changes in their behavior

20

Geographical isolation

Members of the population become separated from another population by geographical barriers that prevent the interchange of genes between the separated populations

For example two types of squirrels being separated by the Grand Canyon

21

Temporal isolation

Species breed/flowers – meet at different times
fireflies – often Breed at different times of night or flowers that bloom at different times of year

22

Agents of evolutionary change

Mutation
Gene flow
Nonrandom mating
Generic drift
Selection

23

Mutation

Causes novel traits to show up through a change in nucleotide sequence

Typically happens slowly. Mutations occur about 1 to 10 times for every hundred thousand cell divisions

Mutation rates are not affected by natural selection

24

Gene flow

Gene flow is the movement of alleles from one population to another

This will introduce new alleles to a population. If these do organisms can survive and reproduce, the gene pool of the population is changed.

Examples include bees pollinating flowers or most oceanic animals

25

Nonrandom mating

Some organisms will meet with organisms of a similar genotype, avoiding a random mating

26

What is inbreeding

A common form of nonrandom meeting. Inbreeding does not change the frequency of alleles, it creates more homozygous individuals.

27

What are examples of nonrandom meeting

Self fertilizing plants, or purebred domestic animals

28

Genetic drift

Random fluctuation of gene frequency for random chance

This random chance can radically change the gene frequencies in a population through Fenno Mena like the bottleneck effect and founder effect

29

What is the bottleneck effect

Happen when a drastic change occurs in a population leaving only a few survivors (natural disasters, disease, overhunting)
Offspring will resemble the survivors simply because those are the only jeans left

30

Founder affects

Occur when a few organisms from a species in habit a new area
Since they are the only representatives of their species the offspring will resemble the only jeans available