5.6, 5.7 and 5.8 Definitions

Question 1

chemosynthetic

Answer 1

Describes organisms that produce organic material using energy released from chemical reactions rather than light.

Question 2

Food chains

Answer 2

Diagram that shows how the energy stored in one organism is passed to another.

Question 3

Food webs

Answer 3

Diagram showing several food chains joined together to demonstrate that animals eat more than one type of food.

Question 4

Trophic level

Answer 4

A level within a food chain, food web or food pyramid.

Question 5

First-order consumer

Answer 5

Organism that is within the second trophic level of a food chain (herbivores); also known as a primary consumer.

Question 6

Primary consumers

Answer 6

The first consumer in a food chain; also known as a first-order consumer.

Question 7

Second-order consumer

Answer 7

Organism that is within the third trophic level of a food chain (carnivores); also known as a secondary consumer.

Question 8

Secondary consumer

Answer 8

The second consumer in a food chain; also known as a second-order consumer.

Question 9

Energy pyramid

Answer 9

A representation of the level of food energy at each level within a food chain.

Question 10

Pyramid of numbers

Answer 10

A representation of the population, or numbers of organisms, at each level within a food chain.

Question 11

Pyramid of biomass

Answer 11

A representation of the dry mass of organisms at each level within a food chain.

Question 12

Birth rate

Answer 12

The number of organisms within a population that are born within a particular period of time.

Question 13

Death rate

Answer 13

The number of organisms within a population that die within a particular period of time.

Question 14

Emigration

Answer 14

The number of individuals leaving an area.

Question 15

Immigration

Answer 15

The number of individuals moving into an area.

Question 16

Exponential growth

Answer 16

A rapid increase in number or size, represented by a J-shaped graph.

Question 17

Sigmoid

Answer 17

The shape of a graph that shows a population increasing in number then reaching a plateau.

Question 18

Steady state

Answer 18

See equilibrium.

Question 19

Plateau phase

Answer 19

See equilibrium.

Question 20

Equilibrium

Answer 20

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.

Question 21

Zero population growth

Answer 21

The point at which birth and death rates balance each other out.

Question 22

Carrying capacity

Answer 22

The maximum population size that a particular environment can sustain.

Question 23

Eutrophication

Answer 23

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.

Question 24

Insecticides

Answer 24

A chemical used to kill insects.

Question 25

Fungicides

Answer 25

A chemical used to kill fungal growth.

Question 26

Herbicides

Answer 26

A chemical used to kill unwanted plants (weeds).

Question 27

Fumigants

Answer 27

A chemical used in the form of smoke or fumes, to kill pests.

Question 28

Bioaccumulation

Answer 28

Magnification of concentrations of a substance such as a nonbiodegradable pesticide along the food chain; also known as biological magnification.

Question 29

Biological magnification

Answer 29

See bioaccumulation.

Question 30

Introduced species

Answer 30

An organism that has been released into an ecosystem in which it does not occur naturally.

Question 31

Nocturnal

Answer 31

Active only at night.

Question 32

Thermoreceptors

Answer 32

Special cells located in your skin, part of your brain and body core that are sensitive to temperature

Question 33

Xerophytes

Answer 33

Plant that is adapted to survive in deserts and other dry habitats.

Question 34

Ephemeral

Answer 34

Lasting for only a very short time.

Question 35

Perennial

Answer 35

Lasting for three or more years.

Question 36

Drought tolerant

Answer 36

Able to tolerate a period of time without water.

Question 37

Drought resistant

Answer 37

Able to store water and hence tolerate long periods of time without water.