Term 3 Test 1 definitions

Question 1

Biosphere

Answer 1

The life-support system of the Earth.

Question 2

Ozone

Answer 2

A gas in the atmosphere made up of particles with three oxygen atoms

Question 3

Biomes

Answer 3

Regions of the Earth divided according to dominant vegetation type

Question 4

Greenhouse effect

Answer 4

A natural effect of the Earth's atmosphere trapping heat, which keeps the Earth's temperature stable. The sun's energy passes through the atmosphere and warms the Earth. Heat energy radiated from the Earth cannot pass through the atmosphere and is trapped.

Question 5

Greenhouse gasses

Answer 5

Gases found in the atmosphere that contribute to the greenhouse effect, trapping the sun's heat (for example, carbon dioxide).

Question 6

Enhanced greenhouse effect

Answer 6

An intensification of the greenhouse effect caused by pollution adding more carbon dioxide and other greenhouse gases to the atmosphere; associated with global warming.

Question 7

Constellations

Answer 7

Groups of stars that were given a particular name because of the shape the stars seem to form in the sky when viewed from Earth.

Question 8

Nebulae

Answer 8

Clouds of dust and gas that may be pulled together by gravity and heat to form a star

Question 9

Parallax

Answer 9

Apparent movement of close stars against the background of distant stars when viewed from different positions around the Earth’s orbit

Question 10

Protostar

Answer 10

The final stage of development of a star in which the temperature is not quite high enough for nuclear fusion to occur.

Question 11

Nuclear fusion

Answer 11

Joining together of the nuclei of lighter elements to form another element, with the release of energy.

Question 12

Apparent magnitude

Answer 12

Brightness of a star as seen from Earth.

Question 13

Absolute magnitude

Answer 13

Actual brightness of a star.

Question 14

Red giant

Answer 14

Star in the late stage of life. Red giants are cooler than main sequence stars and in their core helium is fused to form carbon and other heavier elements

Question 15

Biodiversity

Answer 15

Variation in the many different communities and their environments on Earth.

Question 16

Selective pressure

Answer 16

Factors that contribute to selecting which variations will provide the individual with an increase chance of surviving over others.

Question 17

Selective agents

Answer 17

The different living (biotic) and non-living (abiotic) agents that influence the survival of organisms.

Question 18

Natural selection

Answer 18

Process by which a species gives rise to new species that has characteristics that make them better adapted for survival in a particular environment. This is also called ‘survival of the fittest’.

Question 19

Theory of evolution

Answer 19

A theory about how change occurs in the inherited characteristics of a group of organisms

Question 20

Genetic drift

Answer 20

Changes due to chance events such as floods and fires