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GCSE BIOLOGY PAPER 2 > B7 > Flashcards

B7 Flashcards

1
Q

Define population

A

All the organisms of one species living in a habitat

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2
Q

What is a habitat?

A

A place where an organism lives

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3
Q

Define community

A

The populations of different species living in a habitat

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4
Q

Define ecosystem

A

The interaction of a community of living organisms (biotic) with non-living (abiotic) parts of their environment

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5
Q

Why do organisms compete?

A

Organisms compete with organisms from different and their own species for the same resources. Being successful at competition increases the chance of survival.

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6
Q

What do plants compete for?

A

Plants compete for light, space, water and mineral ions from the soil

e.g. weeds compete with crop plants for light and minerals in the soil

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7
Q

What do animals compete for?

A

Animals compete for food, mates and territory

e.g. male peacocks compete for mates, lions and hyenas compete for food and water.

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8
Q

What is interdependence?

A

A community where each species depend on other species (for food, shelter, pollination, seed dispersal etc.) If one species is removed it can affect the whole community

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9
Q

What is a stable community?

A

One where all the species and environmental factors are in balance so that population sizes remain fairly constant.

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10
Q

What is an abiotic factor?

A

non-living factors of the environment that can affect organisms

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11
Q

Give examples of abiotic factors

A
  • light intensity
  • wind intensity and direction
  • pH of soil
  • moisture level
  • temperature
  • CO2 concentartion
  • mineral content
  • CO2 levels for plants
  • oxygen levels for aquatic animals
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12
Q

What is a biotic factor?

A

a living factor of the environment that affects another organism.

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13
Q

Give examples of biotic factors

A
  • arrival of new predators
  • competition; one species outcompeting another so the numbers are no longer sufficient to breed.
  • pathogens
  • parasites
  • food availabilty
  • decomposers
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14
Q

What are extremophiles?

A

Organisms that live in environments that are very extreme, such as high temperatures, pressures or salt concentration

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15
Q

Give an example of extremophiles

A

bacteria living in deep sea vents

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16
Q

What are the three categories of adaptions?

A
  1. structural - features of an organism’s body structure (e.g. shape or colour)
  2. behavioural- the ways that organisms behave
  3. functional- things that go on the inside an organism’s body that can be related to processes like reproduction and metabolism
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17
Q

Give examples of structural adaptations

A
  • artic fox=white fur- camouflaged against the snow (helps avoid predators & sneak up on prey)
  • polar bears=thick fur- withstand the cold conditions
  • seals=rounded shape- store of fat, low surface area: volume ratio (conserves body heat) brown colour- camouflage from predators
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18
Q

Give examples of behavioural adaptations

A
  • elephants- flap their ears, spray themselves with water- (cool them down) to combat the hot environment
  • swallows- migrate to warmer climates during the winter- to avoid living in cold conditions
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19
Q

Give examples of functional adaptations

A
  • desert animals(e.g. camels)- conserve water by producing very little sweat and small amounts of concentrates urine. Fat(in hump) that can be broken down into water
  • brown bears- hibernate during winter- lower their metabolism which conserves energy- no need to hunt when there is limited food available
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20
Q

What is a food chain?

A

A food chain shows what is eaten by what in an ecosystem.

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21
Q

What do all food chains start with?

A

a producer e.g. algae, green plants

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22
Q

What happens in a stable community?

A

The numbers of predators and prey rise and fall in cycles

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23
Q

Explain the relationship between prey and predators

A

(the population of a species is limited by the food availability)
- if the population of the prey increases, so will the population of predators
- as the population of predators increases, the number of prey will decrease
- fewer prey= fewer predators
- the number of prey is able to rise again

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24
Q

Why are predator-prey cycles always out of phase with each other?

A

It takes a while for one population to respond to changes in the other population

25
Q

True or false: All materials in the living world are recycled to provide the building blocks for future organisms.

A

True

26
Q

What does the carbon cycle do?

A

The carbon cycle returns carbon from organisms to the atmosphere as co2 to be used by plants in photosynthesis

27
Q

What is the water cycle?

A

The water cycle provides fresh water for plants and animals on land before draining into the seas

  • water is continuously evaporated and precipitated
28
Q

What is compost used as?

A

A natural fertiliser for growing garden plants or crops

29
Q

What does anaerobic decay produce?

A

methane gas

30
Q

What is the function of a biogas generator?

A

produces methane gas as a fuel

31
Q

What environmental changes affect the distribution of species in an ecosystem?

A
  • temperature
  • water availability
  • composition of atmospheric gases
32
Q

What is biodiversity?

A

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

33
Q

How does a great biodiversity ensure the stability of an ecosystem?

A

By reducing the dependence of one species on another for food, shelter and the maintenance of the physical environment.

34
Q

What is rapid growth in the human population and an increase standard of living result in?

A

more resources are used and more waste is produced

35
Q

Give three ways pollution can occur

A
  1. in water, from sewage, fertiliser or toxic chemicals
  2. in air, from smoke and acidic gases
  3. on land, from landfill and toxic chemicals
36
Q

What does pollution do?

A

It kills plants and animals which can reduce biodiversity

37
Q

How do humans reduce the amount of land available for other animals and plants?

A

by building, quarrying, farming and dumping waste

38
Q

What does the destruction of peat bogs do?

A

reduces the area of this habitat and thus the variety of different plant, animal and microorganism species that live there.

39
Q

What does the decay or burning of the peat release?

A

carbon dioxide into the atmosphere

40
Q

Why has large-scale deforestation occurred in tropical areas?

A
  • to provide land for cattle and rice fields
  • grow crops for biofuels
41
Q

What is contributing to ‘global warming’?

A

the increasing levels of carbon dioxide and methane in the atmosphere

42
Q

Give examples of methods used to tackle the problems caused by human impacts on the environment

A
  • breeding programmes for endangered species
  • protection and regeneration of rare habitats
  • reintroduction of field margins and hedgerows
  • reduction of deforestation and carbon dioxide emissions
  • recycling resources rather than dumping in landfill
43
Q

What are the trophic levels?

A
  1. producers- photosynthetic organisms
  2. primary consumers- herbivores
  3. secondary consumers- carnivores that eat herbivores
  4. tertiary consumers- carnivores that eat other carnivores
  5. apex predators- carnivores with no predators
44
Q

Explain the role of decomposers

A

Decomposers break down dead plants and animal matter by secreting enzymes into the environment. Small soluble food molecules then diffuse into the microorganism

45
Q

What does the pyramid of biomass represent?

A

the relative amount of biomass in each level of a food chain

level 1- producers
level 2- primary consumers
level 3- secondary consumers
level 4- carnivores

46
Q

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

A

10%

47
Q

Why is some biomass lost?

A
  • not all the ingested material is absorbed, some is egested as faeces
  • some absorbed material is lost as waste, such as carbon dioxide and water in respiration, water and urea in urine
48
Q

What is food security?

A

Having enough food to feed a population

49
Q

List biological factors which threaten food security

A
  • increasing birth rates
  • changing diets in developed countries → scarce food resources are transported around the world
  • new pests and pathogens that affect farming
  • environmental changes, e.g widespread famine is rains fail
  • conflicts that affect the availability of water or food
50
Q

How can the efficiency of food production be improved?

A

By restricting energy transfer from food animals to the environment, which can be done by limiting their movement and by controlling the temperature of their surroundings

51
Q

What are some animals fed to increase growth?

A

high protein foods

52
Q

Why is it important to maintain fish stocks at a level where breeding continues?

A

to prevent certain species from disappearing altogether in some areas

53
Q

What measures are put in place to combat the declining fish stocks?

A
  • control of net size
  • introduction of fishing quotas
54
Q

What do modern biotechnology techniques enable?

A

Large quantities of microorganisms to be cultured for food

55
Q

What is mycoprotein?

A

a protein-rich food suitable for vegetarians

56
Q

What is the name of the fungus which is useful for producing mycoprotein?

A

Fusarium- the fungus is grown on glucose syrup in aerobic conditions and the biomass is harvested and purified

57
Q

What would a genetically modified bacterium that produces insulin be used for?

A

treating people with diabetes

58
Q

What can genetically modified crops do?

A

provide more food or food with an improved nutritional value e.g. golden rice

GCSE BIOLOGY PAPER 2 (3 decks)

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