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Flashcards in Ecology Deck (41):

Population Density

Describes how many individuals are in a certain area


Three Main Types of Dispersion Patterns

- Clumped: individuals live in packs that are spaced out from each other
- Uniform: individuals are evenly spaced out across a geographic area.
- Random: species are randomly distributed across a geographic area.



Collection of individuals of the same species living in the same geographic area.



Collection of populations of species in a geographic area.



Consists of the individuals of the community and the environment in which it exists.


Biotic Components

Living organisms of the ecosystem.


Abiotic Components

Non-living players in an ecosystem, such as weather and nutrients.



Entire life-containing area of a planet-all communities and ecosystems.


Niche of an Organism

Consists of all the biotic and abiotic resources used by the organism.


Biotic Potential

Maximum growth rate of a population given unlimited resources, unlimited space, and lack of competition or predators


Carrying Capacity

Maximum number of individuals that a population can sustain in a given environment


Limiting Factors

Factors that keep population size in check such as: predators, diseases, food supplies, and waste produced by organisms.


Density-Dependent Factors

-Limiting factors that show up as the population approaches or passes the carrying capacity
-Examples: food supplies that run low, waste products that build up, population-crowding-related disease such as plague.


Density-Independent Factors

Limiting factors that have nothing to do with population size like DISASTER.


Exponential Population Growth

-The population grows at a rate that creates a J-shaped curve
-The population grows as if there are no limitations as to how large it can get.


Logistic Population Growth

-The population grows at a rate that create an S-shaped curve
-Limiting factors are responsible for the S shape of the curve, putting a cap on the size to which the population can grow.


K-selected Populations

-Populations of roughly constant size whose members have low reproductive rates
-The offspring produced require extensive postnatal care until they have sufficiently matured
-Humans are a K-selected species.


R-selected Populations

-Populations that experience rapid growth of the J-curve variety
-Offspring produced are numerous, mature quite rapidly, are require little postnatal care.
-Also known as opportunistic populations and tend to show up when space in a region opens up due to environmental change.


Three Types of Survivorship Curves

-Type I: individuals live a long life until an age is reached where the death rate increases rapidly
-Type II: individuals have a death rate that is roughly constant across all ages
-Type III: individuals have a steep downward curve for those of young age that flattens out as they get older.



-Symbiotic relationship between two organisms in which one organism benefits while the other is unaffected.
-Example: cattle egrets feast on insects that are aroused into flight by cattle that are grazing.



-Symbiotic relationship between two organisms in which both organism reap benefits from the interaction
Example: acacia trees and ants



Symbiotic relationship between two organisms in which one organisms in which one organism benefits at the other's expense
Example: tapeworms in an individual's GI system.


Aposematic Coloration

Warning coloration adopted by animals that possess a chemical defense mechanism.
Predators have grown cautious of animals with bright color patterns due to past encounters with such animals


Batesian Mimicry

An animal that is harmless copies that appearance of an animal that is dangerous to trick predators
Example: a beetle whose colors resemble those of bees


Cryptic Coloration

Those being hunted adopt a coloring scheme that allows them to bend in to the colors of the surrounding environment.


Deceptive Markings

Patterns on animals that can cause a predator to think twice before attacking
Example: some butterflies have colored designs on their wings that resemble large eyes.


Mullerian Mimicry

Two species that are aposematically colored as an indicator of their chemical defense mechanisms mimi each other's color scheme in an effort to increase the speed with which their predators learn to avoid them



Shift in the local composition of species in response to changes that occur over time.


Climax Community

Final stable stage at the completion of a succession process


Primary Succession

Succession that occurs in an area that is devoid of life and contains no soil.


Pioneer Species

Species that is able to survive in resource-poor areas that takes hold of a barren area such as a new volcanic island
Adds nutrients and other improvements to a once uninhabited area until future species are able to take over


Secondary succession

Succession that occurs in an area that once had stable life, but has since been disturbed by some major force such as a forest fire.



Various geographic areas of the Earth that serve as hosts for ecosystems.


Desert Biome

The direst land biome
Experiences a wide range of temperature from day to night
Plants such as cacti have adjusted to desert life and flourish well there
Much of the wildlife is nocturnal
Shows the greatest fluctuation in daily temperatures.


Savanna Biome

Savanna grasslands contain a spattering of trees
Found throughout South America, Australia, and Africa
Soil tends to be low in nutrients
Temperatures tend to be high
Many grazing species live in the biome


Taiga Biome

Characterized by lengthy cold and wet winters
Has gymnosperms as the prominent plant life
Contains coniferous forests


Temperate Deciduous and Forest Biome

Biome that is found in regions that experience cold winters where plant life is dormant, alternating with warm summers that provide enough moisture to keep large trees alive.


Temperate Grassland Biome

Found in regions with cold winters
Soil of this biome is considered to be among the most fertile of all


Tropical Forest Biome

Found all over the planet in South America, Africa, Australia and Asia
Near the equator, these biomes can be rainforests.


Tundra Biome

Extremely cold winters during which the ground freezes completely
Upper layer of the ground thaws during the summer months
Plant life is short shrubs or grasses that can withstand difficult conditions


Water Biome

Freshwater and marine bimes occupy the majority of the surface of the Earth.