AP Biology Chapter 23 Flashcards

6299762866	Mutations	A change in the nucleotide sequence of an organism's DNA, ultimately creating genetic diversity. New genes and new alleles.	0
6299767971	Point mutation	A change in a single base pair of a DNA sequence in a gene. Can be silent or lead to diseases such as sickle-cell disease.	1
6299775703	Chromosomal mutation	delete, disrupt, duplicate or rearrange many loci at once. Often, but not always harmful. Duplications can create expanded genome with new genes that may build over generations and take on new functions.	2
6299836969	Sexual recombination	creates most genetic diversity within a population.	3
6299858905	Crossing over	Process in which homologous chromosomes exchange portions of their chromatids during prophase I meiosis.	4
6299863046	Independent assortment	principle that genes do not influence each other's inheritance because they are separated independently during meiosis. 2 to 23rd power different combinations possible in gamete formation	5
6299883551	Fertilization	Process in sexual reproduction in which male and female reproductive cells join to form a new cell. 2^23 x 2^23 different possible combinations	6
6299915780	Population genetics	Study of allele frequency distribution and change under the influence of evolutionary processes.	7
6299918689	Population	A group of individuals of the same species that live in the same area and interbreed, producing fertile offspring.	8
6299921378	Gene pool	All the genes, including all the different alleles for each gene, that are present in a population at any one time	9
6299926620	Fixed allele	Occurs when the frequency of an allele reaches 100% , all of the members of the population are homozygous. Only 1 allele exists for a gene and results in less genetic diversity.	10
6299938236	Hardy-Weinberg principle	used to describe a population that is not evolving. principle that states that allele frequencies in a population remain constant unless one or more factors ( other than mMendelian segregation and the recombination)cause those frequencies to change.	11
6299969172	Hardy-Weinberg equilibrium	Evolution is not occurring in a population; the rules for this are no mutations, no gene flow, no genetic drift, no natural selection, and only random mating.	12
6299984473	Hardy-Weinberg equation	p + q = 1, p2 + 2pq + q2 = 1;( 3 alleles :1 = (p + q + r)^2 = p^2 + q^2 + r^2 + 2pq + 2pr + 2qr) p=dominant allele q=recessive allele r(if present)=3rd allele(co-dominant or incomplete)	13
6300085294	Natural Selection	A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits. Environment is agent.	14
6300086884	Genetic Drift	A change in the allele frequency of a population as a result of chance events rather than natural selection.	15
6300093115	Founder effect	Genetic drift that occurs when a few individuals become isolated from a larger population and form a new population whose gene pool composition is not reflective of that of the original population.	16
6300095245	Bottleneck effect	Genetic drift resulting from the reduction of a population, typically by a natural disaster, such that the surviving population is no longer genetically representative of the original population.	17
6300097511	Gene flow	When a population gains or loses alleles., movement of alleles into or out of a population due to the migration of individuals to or from the population. lots = populations are more similar	18
6300104189	Relative fitness	The contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals in the population. measure only by reproductive success.	19
6300106995	Directional selection	Form of natural selection in which the entire curve moves; occurs when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve	20
6300109010	Disruptive selection	Natural selection in which individuals on both extremes of a phenotypic range survive or reproduce more successfully than do individuals with intermediate phenotypes.	21
6300112538	Stabalizing selection	A natural selection that favors average individuals in a population; results in a decline in population variation	22
6300117945	Sexual selection	A form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates.	23
6300120831	Diploidy	2N condition maintains and shelters a hidden pool of alleles that may not be suitable for present conditions but that could be advantageous if conditions change	24
6300124171	Heterozygote advantage	Greater reproductive success of heterozygous individuals compared to homozygotes; tends to preserve variation in gene pools. Ex. sickle-cell and malaria	25