BIOL 3040 test 2

Possessing different phenotypes within a population

Environment that an organism lives in

The way genotypes interact with environments

Phenotypic variation: set of traits exhibited by an individual

• A phenotypic defense that can be expressed depending on the environment. 
• Ex.) Daphnia pulex's armor growth in the presence of phantom midge kairomone

• the pattern of phenotypes that an individuals may develop under different environmental conditions
• One genotype does not necessarily give you one phenotype. The level of expression depends on other genotypes as well

• different phenotypes in different environments
• caterpillars exposed to heat shock...

Base position change but no change in amino acids

point mutation that results in an amino acid change

When a stop codon is coded for in a mutation

• unequal crossing over: an error in the genetic recombination that happens during meiosis
• Retrotransposition: When intronless RNA is reverse transcribed into dsDNA and it usually becomes a psuedogene
• Inversions: breakage of chromosomes and the reannealing of chromosomes
• Genome Duplication: plants becoming polyploidy

neutral, lethal, deleterious, beneficial

• benign (optimal)environemt propagated from a single individual at each generation
• propagated from Ig number of individuals and each generation
• start with single individual from mutation line, then propagate as control

population is at genetic equalibrium

Allele frequencies are at equilibrium, no chande so no evolution. only if there is no selection, no mutation, no migration, no chance events, and mating is random

Certain phenotypes die off and allow for higher ratios of allele in the population.

High initial frequencies and selection lead to increase in allele frequecies. High and low lead to lead to an equilibrium, and low and low lead to no frequencies

Allele frequencies (p and q) will change over generation

gene flow

Sampling error in the production of zygotes from a gene pool.

The allele frequencies in the new population are likely, simply by chance, to be different from what they were in the source population.

smaller populations are affected more by genetic drift and larger populations are affected more by selection.

most molecular evolution is a result of drift not natural selection. Deleterious mutations lost to natural selection. Some beneficial mutations are lost at low frequecies due to drift. Some are fixed via natural selections. Much more neutral mutations are fixed as a result of drift

The merging of genealogical as we trace allele copies backward in time

inbreeding: mating among genetic relatives

Among the most important consequences of inbreeding for evolution. results from the exposure of deleterious recessive alleles

• Characters with continuously distributed phenotypes
• Determined by genotype and the environment

Using marker loci to scan chromosomes and find regions containing genes that contribute to quantitative traits.

(Genetic variation)/(Genetic Variation + Variation due to the environment)

(Additive genetic variation)/(Additive genetic variation + Dominance genetic variation + Variation Due to the environment)

• measure survival and fitness
• Quantify trait of interest in those who survived + reproduced vs. those who did not

• number of offspring weaned 
• number of seeds produced
• survival to age of breeding
• etc

Predicted response to selection = heritability times the selection differential

selection that favors one end of the spectrum and disfavors the other end of the spectrume

selection that favors the intermediate phenotype rather than the extremes

selection that favors both extreme phenotypes over the intermediate

• Most populations are not at equilibrium. Steady trickle of mutations lead to genetic variation in fitness related traits.
• Most populations balance beween deleterious mutations and selection for most QTLs, effect on trait is small, so selection on alleles will be weak which leads to genetic variation will persist
• Disruptive selection may be more common than recognized.

a trait or suite of traits, that increases the fitness of an individual compared withindividuals without the trait.

• Traits can be fixed b/c of drift
• some of the traits are completely neutral
• not every trait is an adaptation
• adaptations aren't always perfect

• Conduct an experiment
• observational 
• Comparitive

individuals with the same genotype may have different phenotypes in different environments

• Tradeoffs
• functional constraints
• Lack of genetic variation.