Principles of Ecology

Gregor Mendel, Austrian monk who studied pea plants and inheritance around 1865

Inheritance, trait passed from one generation to another through genes

Allele, alternative form of a gene

Homozygous, two identical alleles for a gene

Heterozygous, two different alleles for a gene

Dominant allele, allele expressed when present and shown as uppercase

Recessive allele, allele masked when dominant allele is present and shown as lowercase

Genotype, genetic makeup of an organism

Phenotype, observable traits of an organism

Character, heritable feature like height or color

Trait, specific form of a character

Law of Independent Assortment, alleles separate independently into gametes

Law of Segregation, paired alleles separate during gamete formation

Parental generation P generation, original parents in a genetic cross

First filial generation F1, offspring of parental generation

Second filial generation F2, offspring of F1 cross

Punnett Square, diagram used to predict offspring genotype probabilities

Linkage, genes inherited together because they are close on a chromosome

Sex linkage, genes located on sex chromosomes affecting inheritance patterns

X linked trait, trait controlled by gene on X chromosome

Autosomal linkage, genes on same chromosome inherited together

Polygenic inheritance, trait controlled by two or more genes

Population ecology, study of population size and growth regulation

Biotic factor, living factor affecting population size

Abiotic factor, nonliving factor affecting population size

Density, number of individuals per unit area

Density dependent regulation, population control that increases with density

Density independent regulation, population control unrelated to density

Natality, birth rate in a population

Mortality, death rate in a population

r, population growth rate equal to births minus deaths

Community ecology, study of interactions between species in an area

Competition, organisms using same limited resource

Symbiosis, close relationship between two species

Mutualism, both species benefit in a relationship

Commensalism, one species benefits and other is unaffected

Parasitism, one species benefits and other is harmed

Succession, change in community over time after disturbance

Habitat, physical place where a species lives

Niche, role of a species in its ecosystem

Island biogeography, study of species distribution on islands

Immigration, arrival of new species to an island

Extinction, disappearance of species from an area

Evolutionary ecology, study of evolution of species interactions