Lecture: #4 (Nurturing Nature: The Power of Culture) Flashcards
Mutation
Direct alteration of DNA
[the ultimate source of variation]
[type of evolution]
[ex) Cystic fibrosis is an inherited disease caused by mutations in a gene called the cystic fibrosis transmembrane conductance regulator (CFTR).]
Somatic cell mutations
affect the individual; not heritable
Germinative cell mutations
Affect sperm or egg cells;heritable
Gene Flow (Migration)
a change in allele frequencies due to the movement of some individuals from one population to another; an agent of evolutionary change caused by the movement of individuals into or out of a population.
[type of evolution]
[ex)
Population
A group of organisms of the same species living in a particular geographic region able to reproduce with each other.
Genetic Drift
Random change in allele frequencies; A random change in allele frequencies over successive generations”
[type of evolution]
[ex) high occurrence of a rare genetic disorder among the Pennsylvania Amish]
Founder Effect and Bottleneck
Fitness
a relative measure of the reproductive success of an individual with a given phenotype compared with the reproductive success of individuals with an alternative phenotype, in a particular environment
(1) “An individual’s fitness is measured relative to other genotypes or phenotypes in the population.”
(2) “Fitness depends on the specific environment in which the organism lives. ”
(3) “Fitness depends on an organism’s reproductive success compared with other organisms in the population.”
Sexual selection
The process by which natural selection favors traits, such as ornaments or fighting behavior, that give an advantage to individuals of one sex in attracting mating partners. [mating choices –> lead to the increased frequency of certain traits in the population.]
[NS: Reproductive Success]
[ex. Male peacocks display their colorful tail feathers with eye spots to attract mates]
Phenotype
The outward expression/manifestation of the genotype and the interaction with the environment.
(e.g., black hair, brown eyes).
Midterm: the outward appearance of an individual; includes physical, biochemical, and physiological features, as well as the individual’s behavior.
Genotype
The genes that an organism carries for a particular trait; also, collectively, an organism’s genetic composition [Internal hereditary factors representing the genetic instructions within an organism]
(e.g., the specific genes for hair and eye color).
Midterm: “an organism’s genetic composition, usually in reference to the alleles carried for a particular trait”
Norm of Reaction
A graph depicting the range of phenotypes from a given genotype in various environments; the set of all phenotypic expressions possible for a given genotype. Genetic makeup is tested to determine if phenotype changes due to the environment.
Steeper lines indicate a significant environmental impact, while flatter lines suggest the genotype plays a more dominant role.
Midterm: A norm of reaction is a graph showing all possible phenotypes that can be produced from a single genotype, if raised in all possible environments. Because reactions norms show the range of different phenotypes that may be obtained from one genotype, depending on environmental conditions, it is a measure of just how important the environment is relative to the genes an individual carries, in determining the phenotype. This is the question raised in most nature vs. nurture debates.
Artificial selection
“A special case of natural selection; the three necessary and sufficient conditions for natural selection are satisfied, but the differential reproductive success is determined by humans rather than by nature and so is typically goal-oriented.”
[NS: Reproductive Success]
[ex. Crops have been bred for a wide variety of traits, such as yield, resistance to pests and diseases, and nutritional value. For example, modern wheat varieties are much higher in yield than wheat varieties that were grown centuries ago.]
