Chapter 5- Population Size And Ecosystems

Question 1

Population

Answer 1

An interbreeding group of organisms of the same species occupying the same habitat

Question 2

Birth Rate

Answer 2

The reproductive capacity of a population; the number of new individuals derived from reproduction per unit time

Question 3

Immigration

Answer 3

The movement of individuals into a population of the same species

Question 4

Equilibrium species

Answer 4

Species that control their population by competition rather than by reproduction and dispersal

Question 5

Environmental resistance

Answer 5

Refers to environmental factors that slow down population growth

Question 6

Biotic

Answer 6

A part of the environment of an organism that is living, e.g. Pathogens, predators

Question 7

Abiotic

Answer 7

A part of the environment of an organism that is non-living, e.g. Air temperature, oxygen availability

Question 8

Carrying capacity

Answer 8

The maximum number around which a population fluctuates in a given environment

Question 9

Abundance

Answer 9

The number of individuals in a species in a given area or volume

Question 10

Distribution

Answer 10

The area or volume in which the organisms of a species are found

Question 11

Ecosystem

Answer 11

A characteristic community of interdependent species interacting with the abiotic components of their habitats

Question 12

Habitat

Answer 12

The place in which an organism lives

Question 13

Community

Answer 13

Interacting populations of two or more species in the same habitat at the time

Question 14

Tropic level

Answer 14

Feeding level; the number of times that energy has been transferred between the sun and successive organisms along a food chain

Question 15

Biomass

Answer 15

The mass of biological material in living, or recently living organisms

Question 16

Saprobiont

Answer 16

A microorganism that obtains its food from the dead or decaying remains of other organisms

Question 17

Gross primary productivity

Answer 17

The rate of reproduction of chemical energy in organic molecules by photosynthesis in a given area, in a given time, measured in kJ m-2 y-1

Question 18

Net primary productivity

Answer 18

Energy in the plant’s biomass which is available to primary consumers, measured in kJ m-2 y-1

Question 19

Primary productivity

Answer 19

The rate at which energy is converted by producers into biomass

Question 20

Secondary productivity

Answer 20

The rate at which consumers convert the chemical energy of their food into biomass

Question 21

Succession

Answer 21

The change in structure and species composition of a community over time

Question 22

Climax community

Answer 22

A stable, self perpetuating community that has reached equilibrium with its environment, and no further change occurs.

Question 23

Primary succession

Answer 23

The change in structure and species composition of a community over time in an area that has not previously been colonised

Question 24

Pioneer species

Answer 24

The first species to colonise a new area is an ecological succession e.g. Algae, lichens and misses in a xerosere

Question 25

Secondary succession

Answer 25

The changes in a community following the disturbance or damage to a colonised habitat

Question 26

Niche

Answer 26

The role and position a species has in its environment, including all interactions with the biotic and abiotic factors of its environment

Question 27

Mutualism

Answer 27

An interaction between organisms of two species from which both derive benefit

Question 28

Commensalism

Answer 28

An interaction of two species from which one benefits but the other is not affected

Question 29

Global warming

Answer 29

The increase of average global temperature, in excess of the greenhouse effect caused by the atmosphere’s historical concentration of carbon dioxide

Question 30

Carbon footprint

Answer 30

The equivalent amount of carbon dioxide generated by an individual, a product or a service in a year

Question 31

Nitrification

Answer 31

The addition of nitrogen to the soil, most commonly as nitrate NO2- and nitrate NO3- ions.

Question 32

Nitrogen fixation

Answer 32

The reduction of nitrogen atoms in nitrogen molecules to ammonium ions by prokaryotic organisms

Question 33

Eutrophication

Answer 33

The artificial enrichment of aquatic habitats by excess nutrients, often caused by run-off of fertilisers