Unit 1 - Conditions for life on Earth - Keywords

Question 1

Physiological function

Answer 1

Any substance that is involved in chemical reactions in a living organism has a physiological function.

Question 2

Specific heat capacity

Answer 2

The measure of the amount of heat energy needed to heat up a particular mass of a material through a particular temperature rise. Water has a high specific heat capacity so it heats up and cools down slowly and has an important role in moderating climatic fluctuations.

Question 3

Thermophilic

Answer 3

Heat-loving, such as the bacteria that live around hot volcanic vents and springs.

Question 4

Ambient gases

Answer 4

The surrounding environmental gases that are available to organisms.

Question 5

Atmosphere

Answer 5

The gases surrounding the Earth. Different layers are characterised by their temperature, density, turbulence and composition.

Question 6

Photolysis

Answer 6

The splitting of molecules by light, including the splitting of water molecules in the early atmosphere, producing oxygen.

Question 7

Greenhouse gas

Answer 7

A gas that absorbs infrared radiation and causes atmospheric heating.

Question 8

Transpiration

Answer 8

The loss of water by evaporation from the stomata of the leaves.

Question 9

Biosphere

Answer 9

All the living organisms on Earth.

Question 10

Hydrosphere

Answer 10

All the water on Earth, found in solid, liquid or gaseous form in a variety of reservoirs, including the oceans, ice caps, rivers and lakes, soil, groundwater, atmosphere and living organisms.

Question 11

Lithosphere

Answer 11

The relatively hard outer layer of the Earth, consisting of the crust and upper layer of the mantle.