AP Environmental Sci Unit 2

Species

organisms that resemble each other, interbreed, & produce fertile offspring

Population

All individuals of the same species in the same place at the same time

Ecosystems

All interactions of communities with each other and with the physical environment

Biosphere

Region on Earth where life can exist

Biome

A major global biotic community characterized by the dominant form of PLANT life and prevailing climate

Amensalism

one is killed & one is not affected

Commensalism

one benefits & other is not affected

Competition

One benefits & one is harmed

Mutualism

Both species benefit.

Keystone Species

The presence of this species contributes to the diversity of species in an ecosystem. ex: wolves in yellowstone

Ecotone

Transition between one biome to another

Hard edge

Less economically friendly, it involves abrupt and clearly defined boundaries between different land uses or ecosystems.

Soft edge

Friendly transitions between different land uses or ecosystems, minimizes abrupt changes allowing for a more gradual shift from one habitat or land use to another.

Stabilizing Selection

the extremes in a population are selected against -extremes die and the average trait survives

Directional Selection

one extreme or another is selected against –  genotype shifts toward the other extreme

Disruptive Selection

Average trait is selected against & both extremes survive! This can create new species

Polyploidy

in plants only – a mutation where an ENTIRE SET of chromosomes is duplicated so offspring have an extra set of chromosomes!

Adaptive Radiation

is rapid speciation to fill ecological niches & is driven by mutation or natural selection.

General Adaptation

develop radical new ability to reach new habitat. EX: FLIGHT

Speciation

is the formation of a new species from existing species

Geographic Isolation

Isolated ecosystems colonized by single species which undergo rapid DIVERGENT Evolution.

Coevolution

two or more species interact & affect  each other’s evolution.  May affect morphology or behavior.                                

Convergent Evolution

organisms not closely related acquire traits while evolving in separate ecosystems. EX: WINGS ON BIRDS AND BATS

Divergent Evolution

2 or more related species becoming MORE dissimilar.

Parallel Evolution

2 interdependent species evolve together at same time & in same ecosystem & acquire similar characteristics        

Gradualism

Evolution is a slow, stepwise development of new species over long periods of time (millions of years) – Traditional view

Punctuated Equilibrium

Some species arose quickly (thousands of years) due to changes in physical or biological environment –   drought, new predator, etc.

Morphological Partitioning

Species use the same resources but have evolved differences in body shape for the same purpose. EX: different bee species have different lengths to get nectar from flowers.

Spatial Partitioning

Organisms use different area or habitats for the same resource. EX: Bird species hunt and nest in different parts of the same tree.

Temporal Partitioning

Many species use the same limited resource but at different times. EX: Hawks and owls use the same food source, day vs. night.

Resource Partitioning

When essential resources are some organisms will often evolved  them to avoid competition

Specialist

organisms that occupy a narrow niche, they don’t tolerate change in the environment, and they are very prone to extinction

Generalist

organisms that tolerate change and can adapt to any environment .

Indicator species

An organism that is used to assess the health of an overall environment. EX: the kelp in the sea is sensitive to water quality.

Intraspecifc

Competition between organisms of the same species for resources

Interspecific

Competition over resources between different species.

The limit of tolerance

The range in which organisms can continue to execute activities, cannot operate under extremes.

Zone of Stress

Environmental conditions in which an organism experiences stressful conditions such as reduced growth that arent lethal.

Primary succession

Builds an ecosystem from scratch

Secondary Succession

builds up ecosystem from already existing ecosystem.