Niche Reading

Definitions

Hypothesis

A proposed explanation for something that researchers have observed.

Prediction

A statement of an outcome that should occur if a hypothesis is correct.

Null hypothesis:

A hypothesis that represents the "not" or "no-effect" contrast to the hypothesis being tested.

Treatment (or experimental) group:

A group that experiences experimental conditions that conform to the mechanism proposed in the hypothesis.

Control group:

A comparison group that represents the normal or no-treatment condition to contrast with groups that experience experimental manipulation. 

Controlled conditions:

Aspects of an experimental design that are used in both control and experimental treatments to eliminate bias among treatments and reduce influence from confounding factors.

Outcome variable:

The variable that is measured in an experimental or observational study. It represents a quantity that is relevant to the hypothesis being tested.

Ecosystem services:

Goods and services provided to humans by the natural environment such as oxygen, high-quality and abundant water, productive soils, food and fiber, and recreational and spiritual resources.  

Humus:

Soil organic matter originating in decaying plants roots, leaves, and stems.

Niche:

The range of abiotic and biotic conditions that a species lives in.

Fundamental niche:

The possible range that a species can tolerate, which defines the types of habitats where a species can potentially occur.

Realized niche:

The actual range that a species occupies, given the constraints of biotic and abiotic factors.

Acclimation:

a phenotypic change that helps an individual cope with a change in conditions.

Adaptation:

a change in allele frequencies that increases average fitness in a population in a particular environment.

Evolution: 

a change in allele frequencies across generations.

Biotic factors: 

interactions, such as predation, parasitism, mutualism, or competition, that influence whether a species is found in a given area.

Abiotic factors: 

physical conditions, such as temperature, moisture availability, and soil chemistry, that influence whether a species is found in a given area.

Independent Variable