Biological wealth
Living things are responsible for the structure & maintenance of all ecosystems
Biodiversity
an area's sum total of all organisms; The diversity of species, their genes, populations, & communities
Biological evolution
genetic change in populations of organisms across generations; May be random, or directed by natural selection
Selection
the process by which traits that enhance survival and reproduction are passed on more frequently to future generations than those that do not
Adaptation
a trait (characteristic) that promotes reproductive success
Mutations
accidental changes in DNA that may be passed on to the next generation
Artificial selection
the process of selection conducted under human direction
Population
a group of individuals of a species that live in the same area
Species
a population or group of populations whose members share characteristics and can freely breed with one another and produce fertile offspring
Extinction
the disappearance of a species from Earth
Threatened
species numbers are nearing critical stage
Ecology
the study of interactions among organisms and their environment
Population ecology
investigates the quantitative dynamics of how individuals within a species interact
Community ecology
focuses on interactions among species
Ecosystem ecology
studies living and non-living components of systems to reveal patterns; Nutrient and energy flows
Habitat
the specific environment in which an organism lives
Habitat use
each organism thrives in certain habitats, but not in others
Habitat selection
the process by which organisms actively select habitats in which to live
Niche
an organism's use of resources and its functional role in a community
Specialists
species with narrow niches and very specific requirements
Generalists
species with broad niches that can use a wide array of habitats and resources
Population density
the number of individuals within a population per unit area
Limiting factors
physical, chemical, and biological characteristics that restrain population growth
Environmental resistance
all limiting factors taken together that stop exponential growth