The seasonal movement of a complete population of animals from one area to another.

A process of developing.

The elimination by an organism of waste products.

The physical processes (as breathing and diffusion) by which a living thing obtains the oxygen it needs to produce energy and eliminate waste gases (as carbon dioxide).

To pass the summer in an inactive or resting state.

To pass the winter in a sleeping or resting state.

A rapid learning process by which a newborn or very young animal establishes a behavior pattern of recognition and attraction towards other animals of its own kind.

Two stimuli are linked together to produce a new learned response in a person or animal.

Learning in which an animal comes to associate particular behaviors with the consequences they produce.

The waning of an animal’s behavioral response to a stimulus, as a result of a lack of reinforcement during continual exposure to the stimulus.

The natural progression from a previous, simpler, or embryonic stage to a later, more complex, or adult stage.

The processes by which an animal or plant takes in and makes use of food substances.

The production of a new living thing by two parent organisms, with each parent contributing half the material in the DNA of the offspring.

A type of reproduction by which offspring arise from a single organism, and inherit the genes of that parent only.

The classification and naming of organisms in an ordered system that is intended to indicate natural relationships, especially evolutionary relationships.

Traits shared by the members of a group of organisms with many similarities.

A branching treelike diagram used to illustrate evolutionary (phylogenetic) relationships among organisms.

A tool created by scientists to help scientists and people identify objects and organisms.

Any member of the mammalian group characterized by the presence of a placenta, which facilitates exchange of nutrients and wastes between the blood of the mother and that of the fetus.