Key Terms for Exam II, Practice questions, Old quiz questions Flashcards
Species exist when they are _____ from one another because of a lack of _____.
Genetically isolated from one another because of a lack of gene flow.
Divergence in traits such as genitalia shape prevents fertilization. What specific type of pre-zygotic isolation is this known as?
Mechanical isolation
When there is high allelic diversity within a population, is there a good or bad chance of evolution?
Good chance
Dispersal and vicariance result in _____ speciation.
Allopatric speciation
The _____ looks at genetic divergence as well as morphological traits.
Phylogenetic species
The _____ considers evolutionary independence due to reproductive isolation.
Biological species concept
The _____ is the primary way in which fossils are assigned to species
Morphospecies concept
Allele frequencies do not change very much due to _____. And in no case will an allele be lost.
Genetic drift
Allelic frequency increases over generations. This is due to what?
Selection
Allelic frequency decreases over time and eventually the allele is lost. This is due to?
Deleterious mutation
Mutations that affect cells in the body
Somatic mutations
Mutations that affect games and can be passed from parents to offspring
Germ-line mutations
A trait for which multiple, discrete phenotypes can arise from a single genotype depending on environmental circumstances
Polyphenic trait
A signaling molecule that flows between nearby cells and acts directly to alter expression of target genes
Morphogen
Measurable phenotypes that vary among individuals over a given range to produce a continuous distribution of phenotypes
Quantitative traits
A type of genetic drift describing the loss of allelic variation that accompanies formation of a new population
Founder effect
Occurs when the effects of an allele at one locus are modified by alleles at one or more other loci
Epistasis
Selection that favors more than one allele. It acts to maintain genetic diversity
Balancing selection
This is when rare genotypes have higher fitness than common genotypes. This process can maintain genetic variation in a population.
Negative frequency-dependent selection
An allele that yields twice the phenotypic effect when two copies are present at a given locus than when only a single copy is present is known as…
An additive allele
Natural selection is ineffective in a _____ population and effective in _____ ones.
Small - ineffective
Large - effective
Based on the options above, _____ most specifically defines when two rival males
compete.
Interspecific conflict
Based on the options above, _____ more generally defines when two rival males
compete.
Intraspecific conflict
Sharp-shooters have a morphological trait known as a _____.
Bacteriome
The sharp-shooter example most correctly represents an example of _____.
Endosymbiosis
_____ is when species interact antagonistically in a way that results in each species
exerting reciprocal directional selection on the other.
Coevolutionary escalation/arms race
A relationship involving two species in which one species benefits but the other suffers no loss of fitness is
known as _____.
Positive/neutral commensalism
One of several alternative forms of DNA sequence of same locus
Allele
A form of cell division that occurs only in eukaryotes. # of chromosomes cut in half
Meiosis
Exchange of genetic material between paired chromosomes during meiosis
Genetic recombination
Alleles that produce the same phenotype whether they are paired with an identical allele or a different allele
Dominant allele
Alleles that produce their characteristic phenotype only when they are paired with an identical allele
Recessive allele
Changes in the phenotype produced by a single genotype in different environments
Phenotypic plasticity
The study of distribution of alleles within populations and the mechanisms that cause allelic frequencies to change over time
Population genetics
The specific locus of a gene or piece of DNA sequence on a chromosome
Genetic locus
This theorum proves that in absence of genetic drift, mutation, selection, migration, allele frequencies at a genetic locus will not change from one generation to the next
Hardy-Weinburg equilibrium
An allele becomes _____ in a population when all of the alternative alleles have disappeared
Fixed
The success of an organism at surviving and reproducing, contributing offspring to future generations
Fitness
Success of the genotype at producing new individuals standardized by the success of other genotypes in the population
Relative fitness
Difference between average fitness of individuals bearing the allele and average fitness of population as a whole
Average excess of fitness
Condition when a mutation in a single gene affects the expression of many different phenotypic traits
Pleiotropy
Selection that decreases the frequency of alleles within a population
Negative selection
Selection that increases the frequency of alleles within a population
Positive selection
The probability that the two alleles at any locus in an individual will be identical by descent
Inbreeding coefficient
A reduction in the average fitness of inbred individuals relative to that of outbred individuals
Inbreeding depression
A group of spatially separated populations of the same species that interact at some level
Metapopulation
Species are metapopulations of organisms that exchange alleles frequently enough that they comprise the same gene pool and therefore same evolutionary lineage
General lineage species concept
An aspect of the environment, genetics, behavior, physiology, or ecology of a species that reduces or impedes gene flow from individuals of other species
Isolation barrier
Evolutionary process by which new species arise
Speciation
Occurs when populations are in separate, non over-lapping geographic areas
Allopatric
Occurs when populations are in same geographic area
Sympatry
Occurs when reproductive barriers prevent or strongly limit reproduction between populations
Reproductive isolation
Occurs when sperm or pollen from one species fails to penetrate and fertilize the egg of another species
Gametic incompatibility
Divergence in traits between population that prevents fertilization
Prezygotic isolation
Hybrid offspring that are sterile/infertile
Postzygotic isolation
Breeding at different times pf the year
Temporal isolation
Different calls/mating dances
Behavioral isolation
Reciprocal evolutionary change between interacting species, driven by natural selection
Coevolution
Selection that occurs in two species, due to their interactions with one another
Reciprocal selection
A theory that proposes that the geographic structure of populations is central to the dynamics of coevolution
Geographic mosaic theory of coevolution
Occurs when several harmful/distasteful species resemble each other in appearance, facilitating learned avoidance of predators
Mullerian mimicry
Occurs when harmless species resemble harmful/distasteful species, deriving protection from predators in the process
Batesian mimicry
An increase in genetic diversity caused by the heterogeneity of coevolutionary processes across the range of ecological partners
Diversifying coevolution
Mutualistic organisms that live within the body or cells of another organism
Endosymbionts
An RNA virus that uses an enzyme called reverse transcriptase to become part of the host cells’ DNA
Retrovirus
