Physiological Ecology and Adaptations

Adaptive Response

Organisms adjust physiologically, biochemically, morphologically, or behaviorally to survive environmental change.

Plastic Response

Rapid, reversible changes within an organism's lifetime (behavioral, biochemical, physiological).

Evolutionary Adaptation

Genetic changes across generations that improve survival under long‑term environmental conditions.

Acclimation

Adjustment to new environmental conditions that results in a new physiological steady state.

Conformer

Internal conditions change with external environment (e.g., many invertebrates).

Regulator

Maintains stable internal conditions despite external fluctuations (e.g., fish, mammals).

Performance Hierarchy

Different biological functions have different tolerance ranges (survival > growth > reproduction).

Aerobic Scope

Max metabolic rate minus resting metabolic rate; measures energy available for activity.

Scope for Growth

Energy left for growth and reproduction after metabolic costs.

Osmoconformer

Internal solute concentration varies with external salinity.

Osmoregulator

Actively regulates internal solute concentration; tolerates wider salinity ranges.

Osmolytes

Organic molecules used to regulate cell volume (FAA, urea, glycerol).

Marine Fish Osmoregulation

Drink seawater, excrete salt via gills, produce concentrated urine.

Freshwater Fish Osmoregulation

Do not drink; produce dilute urine; absorb salts through gills.

Salt Glands

Specialized glands in birds, reptiles, and plants that remove excess salt.

Hypoxia

Low oxygen conditions found in intertidal zones, sediments, and oxygen minimum zones.

Oxygen Consumption Patterns

Total O₂ use increases with body size; mass‑specific O₂ use decreases with size.

Diffusion Respiration

Small organisms rely on diffusion across body surfaces for gas exchange.

Gills

High‑surface‑area structures that increase gas exchange efficiency.

Oxygen Pigments

Hemocyanin, hemerythrin, chlorocruorin, hemoglobin — pigments that carry oxygen.

Bohr Effect

High CO₂ lowers pH, reducing hemoglobin's affinity for O₂, releasing oxygen to active tissues.

Photosynthetic Pigments

Pigments absorb different wavelengths; deeper‑living algae use pigments absorbing deeper‑penetrating light.

Visual Adaptations

Surface animals have well‑developed eyes; deep‑sea animals have large, highly sensitive eyes.

Bioluminescence

Organisms produce light using chemical reactions for communication, predation, or camouflage.

Diel Vertical Migration

Daily movement up and down the water column in response to light.

Ecology

Study of interactions between organisms and their environment.

Abiotic Factors

Non‑living environmental components (temperature, salinity, oxygen).

Biotic Factors

Living interactions (competition, predation, symbiosis).