A2 Biology Unit 4 Definitions

Question 1

Eco-System

Answer 1

A self-contained unit made up of all the biotic and abiotic features in a specific area.

Question 2

Population

Answer 2

A group of interbreeding organisms of one species in a particular habitat.

Question 3

Community

Answer 3

All the populations of different organisms living and interacting in a particular place at the same time.

Question 4

Habitat

Answer 4

The place where a community of organisms lives.

Question 5

Niche

Answer 5

How an organism fits into an environment, referring to where it lives and what it does there.

Question 6

Abundance

Answer 6

The number of individuals in a species in a given place.

Question 7

Frequency

Answer 7

The likelihood of a particular species occurring within a quadrat.

Question 8

Percentage cover

Answer 8

An estimate of an area within a quadrat that a particular plant species covers.

Question 9

Biotic

Answer 9

The living part of the environment.

Question 10

Abiotic

Answer 10

The non-living part of the environment.

Question 11

Intra-specific

Answer 11

Within a particular species (when referring to competition).

Question 12

Inter-specific

Answer 12

Between two or more different species (when referring to competition).

Question 13

Predator

Answer 13

An organism that feeds on another organism.

Question 14

Prey

Answer 14

An organism that is consumed by another organism.

Question 15

Ecology

Answer 15

The study of inter-relationships between organisms and their environment.

Question 16

Biosphere

Answer 16

The layer of land, air and water that surrounds the Earth.

Question 17

Producer

Answer 17

Photosynthetic organisms that manufacture organic molecules using light energy, water and carbon dioxide.

Question 18

Consumer

Answer 18

Organisms that obtain energy by feeding on other organisms.

Question 19

Primary consumer

Answer 19

Organisms that obtain energy by feeding on producers.

Question 20

Secondary consumer

Answer 20

Organisms that obtain energy by feeding on primary consumers.

Question 21

Decomposers

Answer 21

Micro-organisms e.g. bacteria and fungi, that break down complex organic molecules into simple components and release minerals and elements into the soil.

Question 22

Detritivore

Answer 22

Small organisms e.g. woodlice and earthworms, that break down the complex organic molecules in dead and decaying plant and animal matter.

Question 23

Saprobiotes

Answer 23

Organisms that break down dead and decaying matter by secreting enzymes and then digesting it.

Question 24

Food chain

Answer 24

A feeding relationship in which the producers are eaten by primary consumers, which in turn are eaten by secondary consumers.

Question 25

Trophic level

Answer 25

The position of an organism within a food chain.

Question 26

Gross production

Answer 26

Total quantity of energy that the plants in a community convert to organic matter.

Question 27

Net production

Answer 27

The rate at which plants can store energy from the sun.

Question 28

Biomass

Answer 28

Total mass of plants and/or animals in a particular place.

Question 29

Dry biomass

Answer 29

Total mass of plants and/or animals in a particular place, minus their water content.