Textbook - Chapter 5: Ecological Genetics Flashcards
Autotrophs
Organisms that produce organic material from inorganic chemicals and some source of energy
Assortive mating
When individuals choose mates nonrandomly with respect to their genotype, or more specifically, select mates based on some phenotypic trait
Allele frequency
The proportion of a given allele among all the alleles present at the locus in the population
Allele
One or two or more alternative forms of a gene that occupies the same relative position or locus on homologous chromosomes
Adaptive radiaiton
Evolution from a common ancestor of divergent forms adapted to distinct ways of life
Adaptation
A genetically determined characteristic (behavioral, morphological or physiological) that improves an organism’s ability to survive and reproduce under prevailing environmental conditions.
Acclimation
Reversible phenotypic changes in an individual organism in response to changing environmental conditions; a form of phenotypic plasticity
Codominance
Occurs when the physical expression of the heterozygous individual is indeterminate between those of the homozygotes. Each allele has specific proportional effect that it contributes to the phenotype
Cline
A measurable, gradual change over a geographic region in the average of some phenotypic character, such as size or coloration; or it can be a gradient in genotypic frequency
Chromosome
One of a group of threadlike structures of different lengths and sizes in the nuclei of cells of eukaryote organisms
Developmental plasticity
Differences in phenotypic traits for a given genotype under different environmental conditions that reflect differences in the allocation of biomass to different tissues (leaves, stem and roots) during the growth and development of the individual plant
Directional selection
Selection favoring individuals at one extreme of the phenotype in a population
Disruptive selection
Selection in which two extreme phenotypes in the population leave more offspring than the intermediate phenotype, which has lower fitness
Dominant allele
An allele that is expressed in either the homozygous or heterozygous state
Evolution
Change in gene frequency through time resulting from natural selection and producing cumulative changes in characteristics of a population
Ecotype
Subspecies or race adapted to a particular set of environmental conditions
Fitness
Genetic contribution by an individual’s descendants to future generations
Gene flow
Exchange of genetic material between populations
Geographic isolates
Groups of populations that are semi-isolated from one another by some extrinsic barrier; compare subspecies
Genotypic frequency
The proportion of various genotypes in a population; compare gene frequency
Genotype
Genetic constitution of an organism
Genome
The collective term for all the DNA in a cell
Gene
Unit material of inheritance; more specifically, a small unit of a DNA molecule, coded for a specific protein to produce one of the many attributes of a species
Gene expression
The process of creating proteins through the genetic code in DNA
Genetic drift
Random fluctuation in allele frequency over time, due to chance alone without any influence by natural selection; important in small populations
Genetic differentiation
When genetic variation occurs among subpopulations of the same species
Gene pool
The sum of all the genes of all individuals in a population
Hardy-Weinberg Principle
The proposition that genotypic ratios resulting from random mating remain unchanged from one generation to another, provided natural selection, genetic drift and mutation are absent
Heterotrophs
Organisms that are unable to manufacture their own food from inorganic materials and thus rely on other organisms, living and dead, as a source of energy and nutrients
Heterozygous
Containing two different alleles of a gene, one from each parent, at the corresponding loci of apair of chromosomes
Homozygous
Containing two identical alleles of a gene at the corresponding loci of a pair of chromosomes
Inbreeding depression
Detrimental effects of inbreeding
Inbreeding
Mating among close relatives
Locus
Site on a chromosome occupied by a specific gene
Mutation
Transmissible changes in the structure of a gene or chromosome
Natural selection
Differential success (reproduction and survival) of individuals that results in elimination of maladaptive traits from a population
Negative assortative mating
Occurs when mates are phenotypically less similar to each other than expected by chance
Norm of reaction
The set of phenotypes expressed by a single genotype across a range of environmental conditions
Phenotype
Physical expression of a characteristic of an organism, determined by both genetic constiution and environment
Phenotypic plasticity
Ability to change form under different environmental conditions
Positive assortative mating
Occurs when maters are phenotypically more similar to each other than expected by chance
Primary producer
Green plant or chemosynthetic bacterium that converts light or chemical energy into organismal tissue
Quantitative Trait
Phenotypic characteristics that have a continuous distribution
Qualitative traits
Phenotypic characteristics that fall into a limited number of discrete categories
Recessive allele
Applies to an allele whose phenotypic effect is expressed in the homozygous state and masked in the presence of an allele in organisms to heterozygous for that gene
Subspecies
Geographical unit of a species population distinguishable by morphological behavioral or physiological characteristics
Stabilizing selection
Selection favoring the middle in the distribution of phenotypes
Selective agent
The environmental cause of fitness differences among organisms with difference phenotypes
Secondary producers
Organisms that derive energy from consuming plant of animal tissue and breaking down assimilated carbon compounds
Target of selection
The phenotypic trait that natural selection acts directly upon
