Section 8 - Ecology & the enviroment

Question 1

Def of habitat

Answer 1

place where organisms live

Question 2

Def of population

Answer 2

All the organisms of one species in a habitat

Question 3

Def of community

Answer 3

All different species in a habitat

Question 4

Def of ecosystem

Answer 4

All the organisms living in a particular area and all the non-living conditions

Question 5

What causes changes in the enviroment?

Answer 5

• abiotic factors (non-living)
• biotic factors (living)

Question 6

Examples of abiotic factors:

Answer 6

1. Enviromental conditions - temperature, light intensity, soil pH
2. Toxic chemicals - pesticides + fertilisers

Question 7

Examples of biotic factors:

Answer 7

1. Availability of food
2. number of predators
3. Competition with other organisms

Question 8

Order of food chains:

Answer 8

1. Producer - plant
2. primary consumer
3. secontay consumer
4. tertiary consumer
5. decomposers - bacteria

Question 9

pyramids of numbers

Answer 9

number of each type of organims in a habitat

Question 10

pyramids of biomass

Answer 10

the weight of all the organisms of each level together

Question 11

pyramids of energy transfer

Answer 11

always pyramid-shaped

Question 12

Energy transfer along food chain steps:

Answer 12

1. Sun
2. Plants
3. Some parts of foods arent eaten by organisms so energy is lost - 90%
4. Most energy transferred to surounding by heat
5. 10% becomes biomass - energy that is trasferred form a trophic level to another

Question 13

Carbon cycle

Answer 13

there is only a fixed amount of carbon on the enviroment so is recycled

Question 14

steps of the carbon cycle

Answer 14

1. whole thing powered by plants and by photosynthesis they transfom co2 into carbohydrates . .
2. carbon compunds pass to animals by eating
3. respiration releases co2 back into air
4. plants and animals when they die are decomposed by bacteria and fungi
5. decomposers release co2 into the air
6. combustion of wood and fossil fuels also releases co2

Question 15

Carbon monoxide

Answer 15

• its poisonous
• created when fossil fuels are burnt without enough air supply
• combined with haemoglobin in red blood cells can prevent them form carrying oxygen

Question 16

Acid rain cause

Answer 16

• Sulfur dioxide comes from sulfur impurities and fossil fuels
• When gas mixed with rain clouds forms dilute sulfuric acid
• caused by internal combustion engines in cars and power stations

Question 17

Greenhouse gases:

Answer 17

• Carbon Dioxide
• Methane - rice growing, cattle rearing
• Nitrous Oxide - fertilisers and vehicle engines
  -CFC - aerosol sprays, fridges

Question 18

Eutrophication def

Answer 18

excesive amount of nutrients in a lake or body of water that causes dense plant growth