Terrestrial Ecology Key Terms

Keystone Species
A species whose presence and role within an ecosystem has a disproportionate effect on other organisms within the system.
Ecology
the study of life
Ecosystem
a system formed by the interaction of a community of organisms with their environment.
Biosphere
the part of the earth’s crust, waters, and atmosphere that supports life.
Biome
A distinct group lifeforms and the environment in which they are found.
Species Diversity
The number of different species in a given area
Species richness
The number of species an ecosystem contains
Species evenness
The number of one individual species an ecosystem contains.
Indicator Species
Species that serve as an early warning of damage to an ecosystem.
Vanishing amphibians
Their life cycles can easily be disturbed causing them to die off.
Foundation species
A species that can create and enhance habitats that can benefit other species in a community.
Population
A group of individual organisms of the same species living w/in a particular area.
Community
The population of all species living & interacting in an area.
Abiotic
nonliving
Biotic
living
Realm of ecology
The spectrum going from organisms to the biosphere
Niche
The total way of life or role of a species in an ecosystem.
Biomass
The organic matter produced by plants; dry weight.
Decomposition
As plant or animal matter dies it will break down and return the chemicals back to the soil.
Predator prey
the relationship between the predators and the prey
Photosynthesis
The process in which glucose is synthesized by plants.
Cellular Respiration
The process in which the plant gives off oxygen
Productivity
The amount of increase in organic matter per unit of time
Range of Tolerance
The spectrum in which the organism flourishes or dies off.
Carrying Capacity
The maximum population of a particular species that a given habitat can support over time.
Biotic potential
The potential an ecosystem has of reaching and then passing the carrying capacity
Heterotroph
Organisms that get their food by eating or breaking down other organisms
Autotroph
Organisms that make the food themselves
Producer
An organism that uses solar energy (green plant) or chemical energy (some bacteria) to manufacture its food.
Herbivore
An organism that feeds directly on all or parts of plants.
Carnivore
An organisms that feeds only on primary consumers
Omnivore
Organism that feeds on both plants and animals
Primary Consumer
A organism that feeds on plants and small organisms
Decomposer
A organism that breaks down waste and dead animals
Detrivore
Insects or other scavengers that feed on wastes or dead bodies.
Detritus
non-living organic waste material
Resource Partitioning
Some species evolve adaptations that allow them to reduce or avoid competition for resources with other species
Tertiary
Animals that feed on animal-eating animals.
Quaternary
Organisms that feed on tertiary and others. Ex: Humans
Nitrogen fixation
This is the first step of the nitrogen cycle where specialized bacteria convert gaseous nitrogen to ammonia that can be used by plants. This is done by cyanobacteria or bacteria living in the nodules on the root of various plants.
Nitrification
Ammonia is converted to nitrite, then to nitrate
Assimilation
Plant roots absorb ammonium ions and nitrate ions for use in making molecules such as DNA, amino acids and proteins.
Ammonification
After nitrogen has served its purpose in living organisms, decomposing bacteria convert the nitrogen-rich compounds, wastes, and dead bodies into simpler compounds such as ammonia.
Denitrification
Nitrate ions and nitrite ions are converted into nitrous oxide gas and nitrogen gas.
This happens when a soil nutrient is reduced and released into the atmosphere as a gas.
Primary Succession
Begins with a lifeless area where there is no soil
Secondary Succession
Secondary begins in an area where the natural community has been disturbed, removed, or destroyed, but soil or bottom sediments remain.
Pioneer Ecosystems
Ecosystems with lichens and moss, for example.