Energy & Feeding Relationships

Vocabulary flashcards reviewing key ecological terms, energy transfer concepts, nutrient cycles, and population growth phases from Cambridge IGCSE Biology notes.

Producers

Organisms that produce their own organic nutrients, usually using energy from sunlight.

Consumers

Organisms that get their energy by feeding on other organisms, classed as primary, secondary, tertiary, or quaternary according to their position in a food chain.

Herbivore

An animal that gets its energy by eating plants.

Carnivore

An animal that gets its energy by eating other animals.

Decomposers

Organisms that get their energy from dead or waste organic material.

Food Chain

A diagram showing the transfer of energy from one organism to the next, starting with a producer.

Food Web

A network of interconnected food chains showing the interdependence of organisms within an ecosystem.

Pyramid of Numbers

A diagram showing how many organisms are present at each trophic level of a food chain, indicated by the width of each box.

Biomass

A measure of the dry mass of an organism, calculated once water has been removed from its tissues.

Pyramid of Biomass

A diagram showing how much living matter (dry mass) is present at each trophic level of a food chain.

Pyramid of Energy

A visual representation of the energy stored at each trophic level of a food chain, highlighting energy loss between levels.

Nitrogen Fixation

The process by which free-living soil bacteria, root nodule bacteria in legumes, or lightning convert atmospheric nitrogen gas ($N_2$) into ammonium compounds or usable nitrates.

Nitrification

The process carried out by nitrifying bacteria that converts soil ammonium compounds into nitrites and then into nitrates.

Denitrification

The process carried out by anaerobic denitrifying bacteria in soil that converts nitrates back into nitrogen gas ($N_2$).

Population

A group of organisms of one species, living in the same area at the same time.

Community

All of the populations of different species in an ecosystem.

Ecosystem

A unit containing the community of organisms and their environment, interacting together.

Sigmoid Population Growth Curve

An S-shaped curve representing population growth over time in an environment with limited resources, consisting of lag, log, stationary, and death phases.

Lag Phase

The initial phase of population growth where organisms adapt to their environment before reproducing, with low population size and minimal offspring production.

Log Phase

The phase of population growth characterized by rapid exponential growth, abundant food supply, rapid birth rate, and low death rate.

Stationary Phase

The phase where population size levels out because an environmental factor becomes limiting, causing birth rate and death rate to be equal.

Death Phase

The phase where population size decreases because death rate exceeds birth rate, typically due to food shortage or toxic waste accumulation.