Microevolution Flashcards
_______ _______ is the differences in alleles within a population
Genetic Variation
Changes in allele frequency within a population over time is called _______
microevolution
_______ _______ is the study of properties of genes in a population
Population genetics
Evolution results in a change in the _______ _______ of a population
genetic composition
Genetic variation is required for _______ to occur
evolution
_______-_______ _______ are used to measure genetic variation
Single-nucleotide polymorphisms
The Hardy-Weinberg equilibrium states that proportions of _______ in a population do not change as long as: No _______ takes place; No genes are _______ to or from other sources (no _______ or _______); _______ is random; The _______ _______ is very large; No _______ occurs
genotypes, mutation, transferred, immigration, emigration, mating, population size, selection
The Hardy-Weinberg principle can be written as an equation: _______ , where the p is the frequency of the 1st allele, and q is the frequency of the 2nd allele
p^2 + 2pq + q^2 = 1
If all 5 assumptions for the Hardy-Weinberg equilibrium are true, _______ and _______ frequencies do not change from one generation to the next
allele, genotype
The ultimate source of genetic variation which makes evolution possible is _______. However, rates are so low that other evolutionary processes are more important in changing _______ _______
mutation, allele frequency
_______ _______ is the movement of alleles from one population to another. This could be physical movement of an animal into a new population, or the drifting of _______ of plants/animals into an area. _______ and _______ can also travel long distances by way of wind
Gene flow, gametes, pollen, seeds
_______ mating can be split into Assortative mating and Disassortative mating
Nonrandom
_______ mating is when phenotypically similar individuals mate, increasing the proportion of _______ individuals
Assortative, homozygous
_______ mating is when phenotypically different individuals mate, increasing the proportion of _______ individuals
Disassortative, heterozygous
In small populations, _______ _______ may lead to allele frequencies changing by chance alone.
Genetic drift
The magnitude of genetic drift is inversely related to _______ _______
population size
Genetic drift can lead to the loss of _______ in isolated populations
alleles
In genetic drift, the _______ _______ is where one or a few individuals disperse and create a new, isolated population.
Founder affect
In genetic drift, the _______ _______ is where there is a drastic reduction in population size due to drought, disease, or other natural forces
bottleneck effect
The bottleneck effect results in a loss of _______ _______
genetic variability
Selection favors certain _______ over others
genotypes
For natural selection to occur: Variation must exist among individuals; Variation among individuals must result in differences in the number of offspring _______ in the next generation; Variation must have a _______ basis
variation, genetic
Natural selection is a _______, while evolution is the historical record or outcome of change through time
process
Widespread use of _______ has led to the rapid evolution of resistance in more than 500 pest species
insecticides
There has been evolution of resistance to _______ in many disease-causing pathogens
antibiotics
_______: Individuals with one phenotype leave more surviving offspring in the next generation than individuals with an alternative phenotype
Fitness
Measuring fitness: The most fit phenotype is assigned a fitness value of __.
1
Measuring fitness: If green toads have 4 offspring and brown toads leave 2.5 offspring, what is the fitness of each?
Green fitness: 4/4 = 1; Brown fitness: 2.5/4 = 0.625
Fitness has many components: _______ (the ability to live), _______ _______ ( some individuals are more successful at attracting mates), _______ of offspring per mating
Survival, sexual selection, number
Selection favors phenotypes with the greatest _______
fitness
When trying to maximize fitness, females evaluate a male’s _______ and decide whether to mate
quality
_______ _______ refers to the energy and time each sex invests in producing and rearing offspring. Females’ is higher
Parental investment
Males best increase their fitness by _______ with as many females as possible
mating
In cases with _______ care, mate choice should be more equal
biparental
_______ _______ - Competitive interactions between members of one sex (usually males) for the opportunity to mate
Intrasexual selection
_______ _______ - Active choice of a mate
Intersexual selection
_______ _______ _______ - Antlers and horns used to combat other males; long tail feathers and bright plumage used to “persuade” members of opposite sex
Secondary sexual characteristics
_______ _______ - Differences between sexes (males larger than females)
Sexual dimorphism
_______ _______ - selects for features that increase probability that a male’s sperm will fertilize the eggs
Sperm competition
_______ _______ - evolution in males of a signal that exploits preexisting biases
Sensory exploitation
_______-_______ selection is where the fitness of a phenotype depends on its frequency within the population
Frequency-dependent
_______ frequency-dependent selection is where rare phenotypes are favored by selection. Maybe they are preyed upon less frequently
Negative
_______ frequency-dependent selection is where common phenotypes are favored. This tends to eliminate variation
Positive
_______ selection is selection that favors one phenotype at one time and another phenotype at another time
Oscillating
Oscillating selection maintains _______ _______ in the population
genetic variation
_______ _______ is where heterozygotes are favored over homozygotes
Heterozygote advantage
Heterozygote advantage works to maintain both _______ in the population
alleles
Many traits are affected by more than one _______
gene
_______ _______ acts to eliminate intermediate types
Disruptive selection
_______ _______ acts to eliminate one extreme
Directional selection
_______ _______ acts to eliminate both extremes, making the intermediate more common
Stabilizing selection
Guppies, they are capable of colonizing portions of streams above _______, meaning they have different _______ methods
waterfall, dispersal
_______ of guppies are rare above waterfalls, leading to _______, more _______ guppies there.
Predators, larger, colorful
_______ _______ eat guppies and _______ don’t
Pike cichlids, killfish
_______ and _______ _______ may counter selection
mutations, genetic drift
Selection is _______ but genetic drift is _______
nonrandom, random
Gene flow can be _______ or _______
constructive, constraining
Constructive gene flow can spread beneficial _______ to other populations
mutation
Constraining gene flow can impede adaptation by continual flow of _______ _______ from other populations
inferior alleles
Some limits of selection are that: One allele can affect multiple _______. There is also a lack of _______ _______
phenotypes, genetic variation
