Biology Exam #4 Flashcards
What is adaption?
the process by which a species becomes fitted to its environment
What is a allele?
One of two or more DNA sequences occurring at a particular gene locus.
What is codominance?
a type of inheritance in which two versions (alleles) of the same gene are expressed separately to yield different traits in an individual
What is disruptive selection?
also called diversifying selection, describes changes in population genetics in which extreme values for a trait are favored over intermediate values.
What is evolution?
the change in heritable traits of biological populations over successive generations.
What is Genetic Drift?
the change in frequency of an existing gene variant in the population due to random chance.
What is genotype?
It can be represented by symbols. For example, BB, Bb, bb could be used to represent a given variant in a gene.
What is heterozygous?
The presence of two different alleles at a particular gene locus. Bb
What is homozygous?
The presence of two identical alleles at a particular gene locus. bb, BB
Incomplete Dominance
results from a cross in which each parental contribution, unique, neither phenotype is present
Macroevolution
evolution above the level of species.
Microevolution
simply a change in gene frequency within a population.
Mutation
Any change in the DNA sequence of a cell. It may be caused by mistakes during cell division, or they may be caused by exposure to DNA-damaging agents in the environment.
Phenotype
The observable characteristics in an individual resulting from the expression of genes; the clinical presentation of an individual with a particular genotype.
Polygenic Inheritance
quantitative inheritance, where multiple independent genes have an additive or similar effect on a single quantitative trait.
Population
a group of individuals of the same species living and interbreeding within a given area
Punnett Square
a table in which all of the possible outcomes for a genetic cross between two individuals with known genotypes are given.
Reproductive Isolation
the inability of a species to breed successfully with related species due to geographical
Sexual Selection
The process by which certain organisms produce more offspring by mating more frequently than other organisms of the same sex and thereby ensure the survival of more of their genetic traits.
Stabilizing Selection
a type of natural selection in which genetic diversity decreases as the population stabilizes on a particular trait value.
True-breeding
sometimes also called a purebred (biology slang: pure line or true-breeding line), is an organism that always passes down certain phenotypic traits (i.e. physically expressed traits) to its offspring of many generations.
Law of Independent Assortment
describes how different genes independently separate from one another when reproductive cells develop.
Law of Segregation
describes how pairs of gene variants are separated into reproductive cells.
Monohybrid
an individual or strain heterozygous for one specified gene.
