Ecology and Environmental Dynamics Study Guide

Practice question-and-answer flashcards covering key ecological principles, hierarchical levels of organization, energy flow, biogeochemical cycles, ecological succession, and biome determinants.

Ecology

The study of interactions among organisms and their biological and physical environments.

Individual organism

A single living creature capable of reproducing fertile offspring.

Population

Members of the same species living in a specific area at a given time.

Community

All interacting populations of living organisms within a defined area.

Ecosystem

A biological community interacting with its physical environment.

Biome

A large geographic region defined by its climate and dominant species.

Biosphere

All parts of Earth inhabited by living organisms.

Self-sustaining ecosystem requirements

Continuous energy, photosynthetic organisms, and nutrient recycling.

Abiotic factors

Nonliving environmental conditions that influence survival and reproduction.

Light intensity

An abiotic factor essential for photosynthesis that influences plant growth.

Temperature range

An abiotic factor affecting metabolic rates and organism survival.

Biotic factors

Living organisms that directly or indirectly influence other organisms.

Limiting factor

An environmental condition that restricts a population's growth, distribution, or size.

Carrying capacity

The maximum population size an environment can sustainably support over time.

Ecosystem energy flow

Energy flows in one direction and eventually dissipates as heat.

Autotrophs

Organisms that synthesize organic food from inorganic substances using light.

Heterotrophs

Organisms that obtain food by consuming preformed organic matter.

Herbivores

Primary consumers that feed on autotrophs.

Carnivores

Consumers that feed on other animals.

Predators

Organisms that actively hunt and kill prey.

Scavengers

Organisms that consume animals killed by other causes.

Omnivores

Consumers that feed on both plant and animal tissues.

Decomposers

Bacteria and fungi that break down organic waste and dead matter, recycling nutrients.

Food chain

A direct sequence showing chemical energy transfer between organisms.

Food web

A network of interconnected food chains.

Energy pyramid

A model showing energy loss at each trophic level.

10% rule

About 10% of ingested energy becomes new biomass available to the next trophic level.

Biomass

The total amount of living organic tissue at an ecosystem level.

Habitat

The physical environment where an organism naturally lives.

Ecological niche

An organism's functional role, behaviors, feeding habits, and interactions within its environment.

Competitive exclusion principle

Species cannot occupy identical niches in the same habitat indefinitely.

Symbiosis

A close, long-term biological relationship between different species.

Mutualism

A relationship in which both species benefit.

Commensalism

A relationship in which one species benefits and the other is unaffected.

Parasitism

A relationship in which one species benefits and the other is harmed.

Matter cycling

Atoms and molecules are continuously recycled between organisms and the nonliving environment.

Photosynthesis in the carbon-oxygen cycle

Autotrophs use carbon dioxide, water, and sunlight to produce glucose and release oxygen.

Cellular respiration in the carbon-oxygen cycle

Organisms use oxygen to break down glucose for ATP, returning carbon dioxide.

Evaporation

The conversion of liquid surface water into atmospheric vapor.

Transpiration

The loss of water vapor from plant leaves.

Condensation

The cooling of water vapor into liquid droplets that form clouds.

Precipitation

Water returning to Earth as rain, snow, sleet, or hail.

Atmospheric nitrogen

Nitrogen gas makes up most of the atmosphere but cannot be directly used by plants.

Nitrogen recycling

Decomposers and specialized soil bacteria convert wastes and dead matter into usable soil nitrates.

Ecological succession

The gradual, predictable change and replacement of a community over time.

Pioneer organisms

The first organisms to colonize a bare or disturbed area.

Intermediate communities

Communities that develop as pioneer species create favorable conditions for other plants.

Climax community

A mature, diverse, stable community that persists unless disrupted.

Primary succession

Succession in an area initially lacking soil and organic life.

Secondary succession

Ecosystem recovery after a disturbance that leaves soil intact.

Biodiversity

The variety of species and genetic variability within ecosystems.

Biodiversity and stability

Greater species diversity improves resilience to major environmental disruptions.

Human benefits of biodiversity

It preserves potential sources of crops, industrial compounds, and medical discoveries.

Fossil fuels and climate change

Burning fossil fuels raises atmospheric carbon dioxide, trapping infrared heat.

Acid rain

Industrial sulfur dioxide and nitrogen oxides react with atmospheric moisture, producing damaging precipitation.

Habitat destruction and fragmentation

Land clearing reduces wildlife habitat and contributes to species loss.