ecology and the environment

Question 1

define population

Answer 1

all the organisms of one species in a habitat

Question 2

define habitat

Answer 2

the place where an organism lives

Question 3

define community

Answer 3

all the different species in a habitat

Question 4

ecosystem

Answer 4

all the organisms living in a particular area 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 ecosystem

Question 6

3 examples of biotic factors

Answer 6

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

Question 7

5 examples of abiotic factors

Answer 7

1) temperature
2) light intensity
3) moisture level
4) pH level
5) toxic chemicals

Question 8

what is a producer

Answer 8

makes its own food using energy from the sun

Question 9

what is a primary, secondary or tertiary consumer

Answer 9

primary consumers eat producers
secondary consumers eat primary consumers
tertiary consumers eat secondary consumers

Question 10

what is a decomposer

Answer 10

they break down dead material and waste

Question 11

why is only about 10% of energy is transferred from one trophic level to the next

Answer 11

most energy is lost in these ways:

1) some parts of the food aren’t eaten/ absorbed, or they are indigestible
2) most of the energy taken in is used for respiration and staying alive
3) most of the energy is transferred to surroundings by heat loss

Question 12

how do you measure the number of plants in a large field

Answer 12

use a quadrat 
random number generator to find where to put it
count how many in the quadrat
repeat
multiply to scale of field

Question 13

causes of sulfur dioxide pollution

Answer 13

volcanic eruptions and fossil fuels

Question 14

biological consequences of sulfur dioxide / nitrogen oxides pollution

Answer 14

dissolve in clouds to form acid rain

• leaching of ions into lakes kills fish
• root hairs less effective at absorbing minerals so tree growth slowed
• acidification of lakes (death of bacteria, fish, algae, change to ecosystem)

Question 15

ways to reduce CO2 production

Answer 15

1. planting of trees
2. less burning of fossil fuels
3. fewer cars / public transport
4. legislation
5. renewable energy

Question 16

advantages of reducing the mass of greenhouse gases released into
the atmosphere.

Answer 16

reduce the greenhouse effect (less heat trapped)
less global warming
fewer ice caps melting
less habitat destruction
less death/extinction of species
less migration
less climate change ( droughts, soil erosion, extreme weather)

Question 17

How can you study distribution across a habitat

Answer 17

Use a belt transects
Mark out a line on the area
Collect the data (eg number of daisies) along the line using quadrats
Plot a graph to see if the changing abiotic factor is correlated with a change in distribution

You would use this to find how a species becomes more or less common as you move from an area of shade to sun

Question 18

What is the difference between pyramids of numbers and biomass

Answer 18

Pyramids of numbers:
Each bar shows the number of species in that trophic level

Pyramids of biomass:
each bar shows the mass of living material in that trophic level

Biomass is always pyramid shaped; number isn’t

Question 19

what is nitrogen fixation

Answer 19

turning Nitrogen gas into nitrogen compounds

Question 20

what is nitrification

Answer 20

turning ammonium ions in decaying matter into nitrates

Question 21

what is decomposition (in the nitrogen cycle)

Answer 21

breaking down proteins (in rotting plants and animals) and urea and turning them into ammonia/ ammonium ions in soil

Question 22

what are the consequences of deforestation

Answer 22

1) leaching
2) soil erosion
3) disturbing the balance of CO2 and O2
4) disturbing evapotranspiration

Question 23

what is leaching

Answer 23

when trees are removed nutrients get leached away but don’t get replaced, leaving infertile soil

Question 24

what is soil erosion

Answer 24

tree roots hold the soil together

when trees are removed, soil can be washed away by the rain leaving infertile ground

Question 25

how does deforestation disturb the balance of C02 and 02

Answer 25

less photosynthesis so less oxygen produced

combustion releases C02

Question 26

how does deforestation disturb evapotranspiration

Answer 26

when trees are cut down evapotranspiration is reduced making local climates drier

Question 27

what is eutrophication

Answer 27

1) fertilisers enter the water, adding extra nutrients
2) the extra nutrients cause algae to grow fast and block the light
3) plants can’t photosynthesise without light so start to die
4) the dead fish provide food for decomposers, so the number of decomposers (bacteria) increase.
5) decomposers respire using up the oxygen causing organisms which need oxygen to die