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
