B18 Biodiversity and ecosystems

Question 1

what is biodiversity?

Answer 1

the variety of all the different species of organisms on Earth, or within an ecosystem

Question 2

what does high biodiversity ensure?

Answer 2

stability in ecosystems by reducing dependence on one species for food, shelter and maintenance of the physical environment

Question 3

how does an increasing human population affect land and the environment?

Answer 3

• land used for building and farming which destroys habitats and reduces biodiversity
• quarrying reduces land available for other organisms
• wasted produced by humans pollutes the environment and processing takes up land

Question 4

how is land being polluted?

Answer 4

• sewage
• household waste and industrial waste in landfill
• toxic chemicals leaching into soil
• pesticides used in farming

Question 5

how is water being polluted?

Answer 5

• sewage
• fertilisers
• toxic chemicals (pesticides, herbicides)

Question 6

what is eutrophication?

Answer 6

• pesticides run off into a body of water and cause increased growth of algae
• this blocks light and stop other plants photosynthesising so they die
• microbes decompose the dead plants and use up lots of oxygen in the water
• there is now not enough water to support other organisms so they die and are decomposed
• this causes more oxygen to be used up
• the water body then becomes dead

Question 7

how is acid rain formed?

Answer 7

sulfur dioxide gas and nitrogen dissolve in rainwater after being formed by burning fossil fuels with impurities

Question 8

what are the effects of acid rain?

Answer 8

• directly damages plants and roots
• causes water bodies to become too acidic

Question 9

what is smoke pollition?

Answer 9

solid particulates in the air

Question 10

what is the effect of smoke pollution?

Answer 10

• the particle reflect sunlight so less light hits the surface of the earth
  this causes a dimming effect
• it can also damage human health directly

Question 11

what is smog?

Answer 11

a haze of small particles and acidic gases

Question 12

what are the reasons for deforestation?

Answer 12

• to grow staple foods
• to rear more cattle
• to grow crops for biofuels

Question 13

how does deforestation increase the amount of CO2?

Answer 13

• burning the trees releases CO2 from combustion. the microbes that decompose the dead material also release CO2
• it also reduces the rate that CO2 is removed from the atmosphere

Question 14

how is peat made?

Answer 14

when plant material cannot decay completely because of acidic conditions or lack of oxygen

Question 15

what is peat used for?

Answer 15

fuel
used in gardens as fertiliser

Question 16

what does a loss of peat bogs mean?

Answer 16

loss of biodiversity
more CO2

Question 17

what contributes to global warming?

Answer 17

increasing levels of methane and CO2

Question 18

what are the effects of global warming?

Answer 18

• loss of habitats
• change in distribution
• change in migration patterns
• reduced biodiversity

Question 19

what affects the distributionof species in an ecosystem?

Answer 19

• availability of water
• temperature
• atmospheric gases

Question 20

how can biodiversity be maintained?

Answer 20

• breeding programs
• protection and regeneration of rare habitats
• reintroduction of field margins and hedgerows
• reduction of deforestation and CO2 emissions
• recycling resources

Question 21

what are trophic levels?

Answer 21

the position of organisms within a food chain

Question 22

what is in trophic level 1?

Answer 22

producers

Question 23

what is in trophic level 2?

Answer 23

primary consumers (herbivores)

Question 24

what is in trophic level 3?

Answer 24

secondary consumers (carnivores who eat herbivores)

Question 25

what is in trophic level 4?

Answer 25

tertiary consumers (carnivores who eat secondary consumers)

Question 26

what are apex predators?

Answer 26

carnivores with no predators

Question 27

what do decomposers do?

Answer 27

break dowm dead material by secreting enzymes into the environment

Question 28

how is biomass measured?

Answer 28

the dried mass of biological material in grams
OR
wet biomass in grams

Question 29

what is the problem with using dry biomass?

Answer 29

you have to kill the living organism

Question 30

why is there less biomass at each trophic level?

Answer 30

• not all parts of the organism are eaten
• some biomass is passed out and lost as waste material
• biomass is used in respiration

Question 31

how much energy from the sun is used by producers for photosynthesis?

Answer 31

1%

Question 32

how much biomass from each trophic level is transferred to the level above it?

Answer 32

approx. 10%

Question 33

how is biomass lost in an organism?

Answer 33

not all ingested material is absorbed

Question 34

how is biomass lost in organisms?

Answer 34

• lost in faeces
• lost in waste products of respiration and urine
• glucose is used in respiration

Question 35

what is food security?

Answer 35

having enough food to feed a population

Question 36

what factors affect food security?

Answer 36

• increasing birth rates
• changing diets meaning food has to be transported
• new pests and pathogens
• environmental changes
• const of agricultural inputs
• conflicts

Question 37

what are factors to consider when looking at sustainable food security?

Answer 37

• maintaining soil quality
• efficient ways to produce food
• take care of fish stocks

Question 38

what does decreasing the number of stages in a chain do?

Answer 38

increase the efficiency of food production

Question 39

how can the efficiency of food production be artificially managed?

Answer 39

• limiting movement of animals
• controling temperature of surroundings
• high protein diets

Question 40

what is the advantage of fish farming?

Answer 40

it protects wild stocks of fish and produces cheap protein

Question 41

what is the disadvantage of farming fish?

Answer 41

ethical concerns about the artificial conditions

Question 42

how can overfishing be reduced?

Answer 42

• controlling net sizes
• introduce quotas

Question 43

how is mycoprotein produced?

Answer 43

• fusarium is grown on glucose syrup in aerobic conditions
• the biomass is harvested and purified
• it is then dried and shaped

Question 44

what are GM crops used for?

Answer 44

they are developed for increased yields or better nutrition

Question 45

how is insulin produced?

Answer 45

genetically modified bacteria