5.6, 5.7 and 5.8 Definitions Flashcards
chemosynthetic
Describes organisms that produce organic material using energy released from chemical reactions rather than light.
Food chains
Diagram that shows how the energy stored in one organism is passed to another.
Food webs
Diagram showing several food chains joined together to demonstrate that animals eat more than one type of food.
Trophic level
A level within a food chain, food web or food pyramid.
First-order consumer
Organism that is within the second trophic level of a food chain (herbivores); also known as a primary consumer.
Primary consumers
The first consumer in a food chain; also known as a first-order consumer.
Second-order consumer
Organism that is within the third trophic level of a food chain (carnivores); also known as a secondary consumer.
Secondary consumer
The second consumer in a food chain; also known as a second-order consumer.
Energy pyramid
A representation of the level of food energy at each level within a food chain.
Pyramid of numbers
A representation of the population, or numbers of organisms, at each level within a food chain.
Pyramid of biomass
A representation of the dry mass of organisms at each level within a food chain.
Birth rate
The number of organisms within a population that are born within a particular period of time.
Death rate
The number of organisms within a population that die within a particular period of time.
Emigration
The number of individuals leaving an area.
Immigration
The number of individuals moving into an area.
Exponential growth
A rapid increase in number or size, represented by a J-shaped graph.
Sigmoid
The shape of a graph that shows a population increasing in number then reaching a plateau.
Steady state
See equilibrium.
Plateau phase
See equilibrium.
Equilibrium
A state in which conditions are balanced and there is neither growth nor a decrease in number; also known as steady state or plateau phase.
Zero population growth
The point at which birth and death rates balance each other out.
Carrying capacity
The maximum population size that a particular environment can sustain.
Eutrophication
A form of water pollution involving an excess of nutrients such as nitrates and phosphorus, resulting in algal blooms and possible death of fish and other organisms.
Insecticides
A chemical used to kill insects.
