CK-12 Biology Notes: Experiments and Population Ecology (Audrey Tosch)

Vocabulary flashcards covering key concepts from the lecture notes on experiments and population ecology, including variables, population concepts, distribution, habitat, and density-related factors.

Experiment

A special type of scientific investigation performed under controlled conditions, usually in a laboratory.

Controlled experiment

An experiment designed to keep all variables constant except the independent variable, typically conducted under controlled conditions in a laboratory.

Hypothesis

A proposed explanation to be tested by an experiment; data should be able to confirm or reject it.

Independent variable

The variable that affects the dependent variable.

Dependent variable

The variable that is observed or measured in an experiment.

Example of a controlled experiment

An experiment where some plants receive fertilizer and others do not, used to test the effect on plant growth.

Sample size

Size of the sample used in an experiment.

Repetition

Repeating the lab more than once.

Species

Group of organisms that can mate with one another to produce fertile offspring.

Community

Communities are made up of populations of different species.

Population

A group of organisms of the same species that live in the area.

Biology

Study of life.

Natural selection

Process in which organisms best suited to their environment are more likely to survive and pass on their traits to future generations.

Population size

Number of individuals in a population.

Extinction

A species completely dies out and no members remain.

Population density

Average number of individuals in a population per unit of area.

Population distribution

Measure of how individuals in a population are spread throughout their habitat.

Habitat

Physical environment in which a species lives and to which it has become adapted.

Demography

Statistical study of populations.

Clumped distribution

Organisms clustered in groups.

Random distribution

Organisms have an unpredictable distribution.

Uniform distribution

Organisms are evenly spaced over the area they occupy.

Immigration

Arrival of individuals into a population from other areas.

Emigration

Departure of individuals from a population to other areas.

Birth rate

Rate at which new individuals are born in a population.

Death rate

Rate at which individuals die in a population.

Infant mortality

Rate of infant deaths; has a huge impact on population dynamics.

Density-dependent factors

Factors that can affect population size depending on how densely populated the area is.

Density-independent factors

Factors not influenced by population size or density; affect all species similarly in the ecosystem.

Population growth rate

Rate at which a population increases or decreases, influenced by births, deaths, immigration, and emigration.