section 8 - ecology and the environment

Question 1

what is a habitat

Answer 1

the place where an organism lives

Question 2

population

Answer 2

all the organisms of one species in a habitat

Question 3

what is a community

Answer 3

all the different species in a habitat

Question 4

what is an ecosystem

Answer 4

all the organisms living in a particular are and all the non-living conditions

Question 5

what is biodiversity

Answer 5

the variety of different species of organisms on earth, or within an ecosytem

Question 6

why is high biodiversity important

Answer 6

makes sure that ecosystems are stable because different species depend on each other for things like shelter or food.

Question 7

what is reducing biodiversity

Answer 7

human actions like deforestation, pollution and global wearing

Question 8

what are 2 abiotic factor which affect communities

Answer 8

1. environmental conditions
2. toxic chemical (eutrophication)

Question 9

what are the biotic factors that affect communities

Answer 9

1. availability of food
2. number of predators
3. competition

Question 10

how much energy is lost between trophic levels

Answer 10

around 90%

Question 11

what does the the 10% of total energy available for

Answer 11

biomass

Question 12

how is energy lost

Answer 12

1. some parts are eaten (bone) so the energy isn’t taken in
2. some parts are indigestible so pass through organism and come out as waste
3. a lot of energy used in respiration and stalling alive for life processes
4. most transferred to surroundings by heat

Question 13

what does interdependent mean

Answer 13

if one species changes, it affects all the others

Question 14

what are the 7 important points of the carbon cycle

Answer 14

1. green plants use carbon from CO2 to photosynthesise
2. eating passes the carbon compounds in the plant along to animals in a food chain
3. respiration releases CO2 back into the air
4. plants and animals eventually die and decompose
5. decomposers release enzymes which catalysers the break down of dead materials into smaller molecules
6. fossil fuels are made from decayed plant and animal matter burned in combustion and released CO2 into the air
7. CO2 gets released from respiration of the decomposers

Question 15

what happens in the nitrogen cycle

Answer 15

1. nitrogen is needed for making proteins for growth
2. plants get their nitrogen from the soil, so nitrogen in the air has to be turned into nitrogen compounds before plants use it. animals can only get proteins from eating plants.

Question 16

how to measure the rate

Answer 16

the change in the time

Question 17

what is nitrogen fixation

Answer 17

turning N2 from the air into nitrogen compounds in the soil so plants can use

Question 18

how do nitrogen from the air go to the soil

Answer 18

lighting
nitrogen fixing bacteria

Question 19

what are the 4 different types of bacteria in nitrogen cycle

Answer 19

decomposers - break down proteins and urea and turn into ammonia
nitrifying bacteria - turn ammonium ions in decaying matter into nitrates (nitrification)
nitrogen-fixing bacteria - turn atmosphere N2 into nitrogen compounds that plants can use
Denitrifying bacteria - turns nitrates back into N2 (no benefit)

Question 20

what does fossil fuels if they are burnt without enough energy supply produce

Answer 20

carbon monoxide

Question 21

what does burning fossil fuels release

Answer 21

carbon dioxide and sulphur dioxide

Question 22

what does the sulphur dioxide become

Answer 22

sulfur impurities

Question 23

what goes this gas form when mixes with rain clouds

Answer 23

sulphuric acid which falls as acid rain

Question 24

what is the main cause of acid rain

Answer 24

internal combustion engines in cars and power stations

Question 25

what does acid rain cause

Answer 25

changes pH in rivers and many organisms are sensitive.
can kill tres and releases toxic substances from the soil making it hard for the trees to take up nutrients

Question 26

how does human activity cause lots of co2

Answer 26

1. humans release co2 into the atmosphere all the time as part of out every day lives
2. people cut down large areas of forest for timber and to clear land for farming

Question 27

how does human activity cause methane

Answer 27

1. produced naturally from various sources - rotting plants in marshland
2. rive growing and cattle rearing

Question 28

how does human activity cause nitrous oxide

Answer 28

1. naturally by bacteria in soils and the ocean
2. a lot more is released from soils after fertilisers are used
3. vehicle engines and industry

Question 29

how does human activities cause CFCs

Answer 29

1. man0made chemicals. powerful greenhouse gases
2. most countries have agreed not to produce them because it damages the ozone layer that prevents UV radiation
3. some still remain and get released like from leaks from old fridges

Question 30

what happens in eutrophication

Answer 30

1. nitrates and phosphates are put into fields as mineral fertilisers
2. if too much fertilisers is applied and it rains afterward, nitrates are easily leached into rivers and lakes.
3. the result of eutrophication which can cause serious damage to river and lake ecosystems
4. another cause is pollution by sewage. contains lots of phosphates from detergents. it also contains nitrates from urine and faeces.