Shared Flashcard Set

Details

Chapter 26
Vocabulary & Key Concepts
31
Biology
Undergraduate 1
02/16/2014

Additional Biology Flashcards

 


 

Cards

Term
4 processes that can shift allele frequencies in a population over time
Definition
1. natural selection
2. genetic drift
3. gene flow
4. mutation
Term
population
Definition
a group of individuals from the same species that live in the same area at the same time & can interbreed & that vary in the traits they possess
Term
gene pool
Definition
a single group of all of the alleles from all the gametes produced in each generation
Term
Hardy-Weinberg principle: allele frequencies expression
Definition
p + q = 1
Term
Hardy-Weinberg principle: genotype frequencies expression
Definition
p^2 + 2pq + q^2 = 1
Term
5 assumptions that must be met for the Hardy-Weinberg model
Definition
1. random mating
2. no natural selection
3. no genetic drift (random allele frequency changes)
4. no gene flow
5. no mutation
Term
inbreeding
Definition
the mating between relatives
Term
inbreeding increases _____
Definition
homozygosity
Term
deleterious
Definition
alleles that lower fitness
Term
inbreeding depression
Definition
the decline in average fitness that takes place when homozygosity increases & heterozygosity decreases in a population
Term
2 causes of inbreeding depression
Definition
1. many recessive alleles represent loss-of-function mutations
2. many genes - especially those involved in fighting disease - are under intense selection for heterozygote advantage, a selection process that favors genetic diversity
Term
directional selection
Definition
changes the average value of a trait; the average phenotype of a population changes in one direction
Term
stabilizing selection
Definition
reduces variation in a trait; reduce both extremes in a population
Term
disruptive selection
Definition
increases variation in a trait; opposite of stabilizing selection; favors extreme phenotypes at both ends of the range of phenotypic variation
Term
balancing selection
Definition
maintains variation in a trait; occurs when no single allele has a distinct advantage
Term
purifying selection
Definition
when disadvantageous alleles decline in frequency
Term
heterozygote advantage
Definition
heterozygous individuals have higher fitness than homozygous individuals
Term
frequency-dependent selection
Definition
certain alleles are favored when they are rare, but not when they are common
Term
intersexual selection
Definition
the selection of an individual of one gender for mating by an individual of the other gender
Term
intrasexual selection
Definition
individuals compete with one another to obtain mates
Term
2 things which females may choose mates based off of
Definition
1. physical characteristics that signal male genetic quality
2. resources or parental care provided by males
Term
territory
Definition
an area that is actively defended & that provides exclusive or semi-exclusive use by the owner
Term
sexual dimorphism
Definition
any trait that differs between males & females
Term
ecological/environmental selection
Definition
favor traits that enable organisms to do things other than obtain mates - such as survive in their physical & biological environments
Term
genetic drift
Definition
any change in allele frequency in a population that is due to chance
Term
genetic drift is random with respect to _____
Definition
fitness
Term
genetic drift is most pronounced in _____
Definition
small populations
Term
genetic marker
Definition
a specific allele that causes a distinctive phenotype
Term
founder effect
Definition
a change in allele frequencies that occurs when a new population is established
Term
genetic bottleneck
Definition
a sudden reduction in the number of alleles in a population
Term
beneficial
Definition
an allele that allows individuals to produce more offspring
Supporting users have an ad free experience!