Unit 2 Key Terms Flashcards
Adaptation
a new trait that increases an organism’s fitness (ability to survive and reproduce)
Biodiversity
all the different kinds of life you’ll find in one area
Ecological Diversity
The variety of terrestrial and aquatic ecosystems found in an area or on the earth
Ecological Niche
The totality of an organism’s adaptions, its use of resources, and the lifestyle to which it is fitted.
Evolution
(natural selection)
change in the genetic makeup of a population of a species in successive generations; if continued long enough, it can lead to the formation of a new species; affects populations, not individuals
Extinction
Complete disappearance of a species from the earth. It happens when a species cannot adapt and successfully reproduce under new environmental conditions or when a species evolves into one or more new species.
Generalist Species
a species that has a broad niche and is able to adapt to many environmental conditions. They do not have a limited diet and are able to survive by using a variety of resources.
Genetic Diversity
the variety of genes that the variety of species on earth contains; it enables life on earth to adapt to and survive dramatic and environmental changes.
Habitat
the natural home or environment for a human, animal, or organism.
Natural Selection
organisms that are better adapted to their environment survive and reproduce more offspring
Individuals with adaptations pass them on to offspring & individuals without adaptations die off, which leads to the entire population having the adaptation over time
Non-native Species
species that migrate into an ecosystem or are. deliberately or accidentally introduced into an ecosystem by humans
Specialist Species
species with a narrow niche and is not adaptable to change in their environment
Speciation
Formation of two species from one species because of divergent natural selection in response to changes in environmental conditions; usually takes thousands of years.
Species
A group of closely related and interbreeding living things
Species Diversity
the number of different species in an ecosystem and the balance or evenness of the population sizes of all species in the ecosystem
Species Evenness
a measure of how all of the individual organisms in an ecosystem are balanced between the different species
- indicates if there are one or two dominant species, or if population sizes are well balanced
Species Richness
total number of different species found in an ecosystem
- high (r) is generally a good sign of ecosystem health (more species means more quality resources like H2O & soil)
Theory of Island Biogeography
After an island is formed, it will soon be inhabited by organisms. The size and distance from the mainland affect the number of species that the island can support. Immigration rates and extinction rates also play a hand in the number of species on the island
Ecological Succession
the gradual change an ecosystem experiences over time until it reaches stability
A series of predictable stages of growth that a forest goes through
Pioneer Species
appear first, when the ground is simply bare rock or bare soil after a disturbance
Population
a group of organisms of the same species, living in the same area
Primary Ecological Succession
Succession that starts with an essentially lifeless area where there is no soil or bottom sediment in an aquatic area
Range of Tolerance (ecological tolerance)
(range where organisms survive, grow, and reproduce)
range of conditions such as temperature, salinity, pH, or sunlight that an organism can endure before injury or death results
Species and individual organisms both have a range of tolerance for all the different environmental conditions
of their habitat
Resilience
the ability of an ecosystem to return to its original conditions after a major disturbance (wind storm, fire, flood, clear-cutting, etc.)
Secondary Ecological Succession
begins in an area where the natural community of organisms has been disturbed or destroyed, but the soil remains.
