topic 9: ecosystems and environments

Question 1

how can humans affect ecosystems

Answer 1

poaching, farming, consuming, keeping as pets

Question 2

what is food security

Answer 2

having access to enough healthy food at all times.

Question 3

what is eutrophication

Answer 3

adding more nutrients to an ecosystem that normal

Question 4

what things would they lack? Think money

what problems would poorer countries have with food security

Answer 4

not having enough money so not being able to buy good-quality seed, fertilisers, farm equipment, that all increase crop production

Question 5

why could increasing human population affect food security

Answer 5

more people will need more food, there will be less good land for growing food as the available land will be dedicated towards housing

Question 6

what are some advantages of fish farming

Answer 6

mass production of fish, reduces over fishing

Question 7

what is the definition of sustainability

Answer 7

ability to continue something such as food production at the same level without negative effects now or in the future

Question 8

what is the definition of native/indigenous

Answer 8

organisms that have always been in a area/country

Question 9

what is the definition of non-indigenous

Answer 9

organisms that have been introduced into an area

Question 10

what are the steps of the water cycle

Answer 10

1) Water evaporates from oceans, lakes and rivers to form water vapour.
2) As air rises it cools, so water vapour in it condenses to form clouds.
3) As water droplets get too large and heavy, they fall as rain or snow.
4) Rivers flow into lakes and eventually the water returns to the ocean.

Question 11

what is desaliination

Answer 11

process used to produce potable water from salt water by extracting mineral salts (distillation in chemistry

Question 12

define sedimentation

Answer 12

deposition of solid materials at the bottom of water

Question 13

define combustion

Answer 13

burning of organic compounds

Question 14

define photosynthesis

Answer 14

the process in which green plants and some other organisms use sunlight to synthesize nutrients from carbon dioxide and water.

Question 15

define decomposition

Answer 15

process of decay

Question 16

define fossilisation

Answer 16

preservation of organic matter

Question 17

define weathering

Answer 17

break-down/erosion of rocks and sediments

Question 18

what is the word and chemical equation for respiration

Answer 18

glucose + oxygen = carbon dioxide + water (and energy)

C6H12O6 + 6O2 → 6CO2 + 6H2O

Question 19

how would deforestation affect the carbon cycle

Answer 19

-the carbon dioxide stored in the tress will be released into the atmosphere increasing the amount of Co2 in the air

-less trees will mean that the excess co2 in the atmosphere will not be turned into oxygen though photosynthesis

Question 20

why is carbon so important

Answer 20

-found in all living things
-found in air, land and water

Question 21

what role do decomposers play in the ecosystem

Answer 21

they break apart dead organisms into simpler materials making the nutrients available to primary consumers

Question 22

define an ecosystem

Answer 22

all the organisms and the environment in which they live

Question 23

population

Answer 23

groups of the same species within the ecosystem

Question 24

habitat

Answer 24

the particular area in which different populations live

Question 25

Describe how you might use a 1m x 1m quadrat to estimate the number of dandelions in a 100m x 100m field.

Answer 25

.Place multiple tape measures along the length and width of the field, forming a large grid.

.generate 10 random pairs of coordinates

.Calculate the mean number of dandelions per m2.

.estimate the the total population by timesing the average with the total surface area

Question 26

what does abundance refer to

Answer 26

the amount of the population

Question 27

what does distribution refer to

Answer 27

where the individuals of the population are

Question 28

how do scientists use sampling

Answer 28

‘sampling’, where they only measure a subset of the organisms, and use that subset to make predictions about the whole population.

Question 29

what is a transect

Answer 29

A line through a habitat along which organisms are sampled

Question 30

why is it important to have good biodiversity

Answer 30

.It increases the stability of the ecosystem, so that changes are less likely to have adverse affects

.Many species provide specific services, such as pollination

.Many of our medicinal drugs come from wild species

Question 31

what is eutrophication

Answer 31

it’s caused by excess nutrients that have leached into waterways.

Question 32

explain the process of eutrophication through leaching

Answer 32

.fertilisers ‘leach’ into bodies of water (often ponds or still bodies of water)

.the excess nutrients stimulate rapid growth of algae on the surface of the water.

.the algae block sunlight from reaching the plants underneath.

.this prevents the plants from photosynthesising and they begin to die

.decomposers feed on the dead plants and deplete the water from oxygen when they do so

. the animals (fish and stuff) die from lack of oxygen

Question 33

how can the government encourage businesses (including farmers) to reduce damage to biodiversity.

Answer 33

. paying practices for carrying out certain beneficial methods
.setting yearly limits on harmful practices

Question 33

How do field margins and hedgerows in agriculture help increase biodiversity?

Answer 33

they provide extra habitats and food sources so that a wider range of species can survive.

Question 34

Why could the rate of decomposition fall if soil becomes waterlogged?

Answer 34

the oxygen levels will fall, which will decrease the rate of decomposition so there will be less aerobic respiration

Question 35

what are ways to preserve food

Answer 35

.low temperature to slow the rate of decomposition

.air tight containers to prevent microorganisms from contaminating the food

.removing water so microorganisms can’t survive or reproduce

.using gamma radiation to destroy any microorganisms

Question 36

what are some abiotic factors

Answer 36

.temperature
.light
.water
.pollutants

Question 37

what are the biotic factors

Answer 37

competition and predication

Question 38

what are some disadvantages of fish farming

Answer 38

.parasites and disease spread easily as the fish are in close proximity
.