AP Biology Unit 8: Organismal Ecology & Behavioral Adaptations

Homeostasis

The maintenance of a stable internal environment despite external changes.

Endotherms

Organisms that generate heat through metabolism, maintaining a stable internal temperature.

Ectotherms

Organisms that gain heat from external sources, with internal temperature conforming to the environment.

Metabolic Rate

The rate at which an organism uses energy, often inversely related to body size.

Surface-area-to-volume ratio (SA:V)

A key factor affecting heat loss and metabolic rate, higher ratio found in smaller organisms.

Torpor

A physiological state of decreased activity and metabolism used for energy conservation.

Hibernation

Long-term torpor occurring during winter months to conserve energy.

Estivation

Summer torpor to survive high temperatures and low water availability.

Innate Behaviors

Behaviors that are developmentally fixed and genetically controlled, exhibited instinctively.

Learned Behaviors

Behaviors that are developed based on individual experiences, adaptable over time.

Taxis

A directional movement toward or away from a stimulus.

Kinesis

A non-directional change in activity or movement in response to a stimulus.

Phototropism

Growth of a shoot toward or away from light, mediated by the hormone auxin.

Photoperiodism

A plant's response to the length of day and night, affecting flowering and seasonal behaviors.

Phytochrome

The photoreceptor pigment in plants that detects light and regulates flowering based on photoperiod.

Communication

The transmission and reception of signals between organisms, utilizing various methods.

Chemical Signals

Pheromones used for long-distance communication, such as ants following a scent trail.

Visual Signals

Displays used often for courtship or aggression, like a peacock fanning its feathers.

Auditory Signals

Sounds used for communication, effective over distance or in darkness, like bird songs.

Tactile Signals

Communication based on touch, such as the honeybee waggle dance.

Altruism

Behavior that reduces an individual's fitness while increasing the fitness of others.

Inclusive Fitness

The sum of an individual's own reproduction and the reproduction of their close relatives.

Hamilton's Rule

Natural selection favors altruism when the equation rB > C holds true.

Proximate Causation

Explains how a behavior occurs, focusing on mechanics and physiology.

Ultimate Causation

Explains why a behavior evolved, focusing on evolutionary significance.

Fitness (in biology)

The ability of an organism to survive and reproduce, not related to physical strength.

Anthropomorphizing plants

Attributing human desires or feelings to plants, which function based on hormonal responses.