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Biology GCSE 2020 > B7: Ecology > Flashcards

B7: Ecology Flashcards

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1
Q

What is an ecosystem?

A

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

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2
Q

What is a habitat?

A

The natural home/environment of an organism.

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3
Q

What is a population?

A

A group of individuals of one species that live in a given habitat.

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4
Q

What is a community?

A

The term which describes all the populations of different species living in a habitat.

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5
Q

What is an environment?

A

The conditions surrounding an organism/population.

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6
Q

What is interdependence?

A

The dependence of species in a community on each other for things such as food, shelter, pollination and seed dispersal.

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7
Q

What is the importance of interdependence in a community?

A

Species within communities depend on each other for things such as food, shelter, pollination and seed dispersal. Therefore, a change in one aspect of an ecosystem (e.g. one species being removed) can have far-reaching effects on the whole community.

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8
Q

What 6 resources do plants in a community compete for?

A
  • light
  • space
  • water from soil
  • mineral ions from soil
  • seed dispersers
  • pollinators
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9
Q

What 4 resources do animals in a community compete for?

A
  • food
  • mates
  • territory + shelter
  • water
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10
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.

In a stable community, the numbers of predators and prey rise and fall in cycles.

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11
Q

What are abiotic factors?

A

Non-living factors which can affect communities.

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12
Q

List 7 abiotic factors.

A
  • light intensity
  • temperature
  • moisture levels
  • soil pH and mineral content
  • wind intensity and direction
  • carbon dioxide levels (plants)
  • oxygen levels (aquatic animals)
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13
Q

What are biotic factors?

A

Living factors which can affect communities.

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14
Q

List 4 biotic factors.

A
  • availability of food
  • new predators arriving
  • new pathogens arriving
  • one species outcompeting another so that the numbers of the latter are no longer sufficient to breed
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15
Q

What are adaptations?

What are the 3 types of adaptation?

A

Features which organisms have which enable them to survive in the conditions in which they normally live.

Adaptations may be structural, behavioural or functional.

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16
Q

Some microorganisms are adapted to live in very extreme conditions. What are these called?

A

Extremophiles.

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17
Q

Give examples of 3 conditions in which extremophiles can live.

A
  • High temperatures
  • High salt concentrations
  • High pressures
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18
Q

Give one example of a type of extremophile.

A

Bacteria living in deep sea vents.

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19
Q

What is biomass?

A

The mass or energy strored within a given organism.

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20
Q

What are the producers of biomass for life on Earth?

A

Photosynthetic organisms.

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21
Q

Feeding relationships within a community can be represented by food chains. Draw a simple food chain.

A

Producer

↓

Primary consumer

↓

Secondary consumer

↓

Tertiary consumer

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22
Q

What are producers?

A

Organisms at the start of the food chain which synthesise molecules. Usually green plants or algae which make glucose, by photosynthesis, using solar energy.

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23
Q

What are primary consumers?

A

Herbivores that eat plants/algae.

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24
Q

What are secondary consumers?

A

Carnivores that eat herbivores.

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25
Q

What are tertiary consumers?

A

Carnivores that eat other carnivores.

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26
Q

What are apex predators?

A

Carnivores with no predators.

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27
Q

What are trophic levels?

A

They are the levels of the food chain in an ecosystem.

1: producers (plants + algae that produce their own food)
2: primary consumers (herbivores that eat plants/algae)
3: secondary consumers (carnivores that eat herbivores)
4: tertiary consumers (carnivores that eat other carnivores)

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28
Q

Name 2 sampling techniques used to investigate the effect of a factor on the distribution of a species.

A
  • using quadrats to compare abundance in different areas
  • using transects to study how distribution changes across an area
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29
Q

quadrat practical

A

Place a 1m2 quadrat on the ground at a random point within the first sample area. (E.g. divide the area into a grid and use a random number generator to pick coordinates.

Count all the organisms within the quadrat.

Repeat steps one and two as many times as you can.

Work out the mean number of organisms per quadrat within the first sample area.

Repeat steps 1-4 in the second sample area.

Finally compare the two means. (E.g. you might find 2 daises per m2 in the shade and 22 daises per m2 (lots more) in the open field.)

Mean = Total number of organisms / Number of quadrats

30
Q

Students used 0.5m2 quadrats to randomly sample daises on an open field. The students found a mean of 10.5 daises per quadrat. The field had an area of 800m2. Estimate the population of daises on the field.

A

Work out the mean number of organisms per m2.

Then multiply the mean by the total area (in m2) of the habitat.

1 / o.5 = 2 2 * 10.5 = 21 daises per m2.

800 * 21 = 16,800 daises on the open field.

31
Q

transect practical

A

Mark out a line in the area you want to study using a tape measure.

Then collect the data along the line.

You can do this by just counting all the organisms you’re interested in that touch the line.

Or you can collect data by using quadrats. These can be placed next to each other along the line or at intervals, for example every 2m.

32
Q

Why do the populations of predators and prey fluctuate in cycles in stable communities?

A
  • Population of prey increases
  • ↓
  • Population of predators increases
  • ↓
  • Population of prey decreases
  • ↓
  • Population of predators decreases
  • ↓
  • And back to the top.
33
Q

In predator-prey cycles, why are the populations of predators and prey always out of phase with each other?

A

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

34
Q

Approximately what percentage of biomass is transferred from one trophic level to the next?

A

10%.

35
Q

Producers are mostly plants and algae. What percentage of the total incident energy from the Sun’s light do these organisms transfer for photosynthesis?

A

1%.

36
Q

Explain how biomass is lost between the different trophic levels. Give 3 examples.

A
  • Not all material ingested by organisms is absorbed; some is egested as faeces
  • Some absorbed material is lost as waste, e.g. carbon dioxide and water in respiration, and water and urea in urine.
  • Large amounts of glucose are used in respiration.
37
Q

What does the carbon cycle do and how is it important to organisms?

A

It returns carbon from decayed organisms to the atmosphere, as carbon dioxide, to be used by plants in photosynthesis.

Plants are producers, so all consumers directly or indirectly rely on carbon being used for photosynthesis for their food.

38
Q

What does the water cycle do and how is it important for organisms?

A

It provides fresh water for plants and animals on land, before draining into rivers, lakes and seas. Water is continuously evaporated and precipitated.

All organisms respire, and need water from this cycle in order to do this.

39
Q

Explain the role of microorganisms in cycling materials through an ecosystem.

A

Microorganisms break down dead plant and animal matter by secreting enzymes into the environment.

Small, soluble food molecules then diffuse into the microorganism, so that they can respire.

As they respire, microorganisms return carbon to the atmosphere as carbon dioxide, and mineral ions to the soil.

40
Q

What 3 factors affect the rate of decay?

A
  • temperature
  • water/moisture levels
  • oxygen availability
41
Q

Explain how temperature affects the rate of decay of biological material.

A

Raising temperature = more energy, increased rate of enzyme action and therefore increased rate of decay.

But if temperature is raised higher than enzymes’ optimum level, they are denatured and the rate falls.

42
Q

Explain how moisture levels affect the rate of decay of biological material.

A
  • Very low moisture levels mean microorganisms can’t survive
  • Increasing moisture means substances diffuse faster
  • Very high levels of moisture (e.g. peat bogs) mean oxygen bubbles up and away, so rate of decay is inhibited
43
Q

Explain how oxygen availability affects the rate of decay of biological material.

A

More oxygen = increased rate of respiration of microorganisms (so they have more energy to decompose living matter).

Low oxygen levels are typical of waterlogged areas, e.g. peat bogs, where organisms therefore don’t fully decay, and form peat.

44
Q

Gardeners and farmers try to provide optimal conditions for rapid decay of waste biological material. Why is doing this advantageous?

A

The compost produced by decay is used as a natural fertiliser for growing garden plants and crops.

45
Q

What gas does anaerobic decay produce?

A

Methane.

46
Q

What are biogas generators used for?

A

Can be used to produce methane gas as a fuel through the process of anaerobic decay.

47
Q

investigate the effect of temperature on the rate of decay of fresh milk by measuring pH change.

A

.

48
Q

Environmental changes affect the distribution of species in an ecosystem. Give 3 examples of changes which can occur.

A
  • temperature
  • availability of water
  • composition of atmospheric gases
49
Q

Name 3 types of factor which can cause environmental changes.

A
  • seasons/climate
  • geographical factors
  • human activity/interaction
50
Q

What is biodiversity?

A

The variety of all the different species of organisms on earth or within an ecosystem.

51
Q

How is biodiversity important?

A

A great amount of biodiversity ensures the stability of ecosystems by reducing interdependence for food, shelter and maintenance of the physical environment.

52
Q

What 4 human activities reduce biodiversity?

A
  • land use
  • waste
  • deforestation
  • global heating
53
Q

Why are levels of waste increasing?

A

Both of these things mean more resources are used:

  • the growth of the human population
  • the overall increase in living standards
54
Q

In what 3 ways can pollution occur?

A
  • In water, from sewage, fertiliser and toxic chemicals.
  • In air, from smoke and acidic gases.
  • On land, from landfill and toxic chemicals.
55
Q

Why is pollution a problem?

A

It kills plants and animals, which can reduce biodiversity.

56
Q

In what 4 ways do humans reduce the amount of land available for other animals?

A
  • building
  • quarrying
  • farming
  • dumping waste
57
Q

Peat bogs and peatlands are destroyed to produce garden compost, produce fuel and to create space for farmland. Give 3 biological effects of their destruction.

A
  • Reduces the area of this habitat and therefore the level of biodiversity.
  • Burning of peat releases CO2 into the atmosphere (contributes to global heating and reduces biodiversity).
  • Bogs are drained for farmland; exposure to microorganisms means peat is decomposed, releasing CO2 into the atmosphere
58
Q

The destruction of peat bogs and peatlands has numerous detrimental effects. Why don’t we just stop destroying them?

A

There is conflict between:

  • The need for cheaply available compost to increase food production
  • The need to conserve these areas as habitats for biodiversity, as well as avoiding adding to CO2 emissions.
59
Q

Give 2 reasons that large-scale deforestation of tropical areas is carried out.

A
  • providing land for cattle and rice fields
  • growing crops for biofuels
60
Q

Name 4 environmental implications of deforestation.

A
  • Removing vegetation means less CO2 is removed from the atmosphere
  • The combustion or decay of vegetation also releases CO2
  • Decreases biodiversity, risks extinction
  • Deforestation is done either to create space for crops (agricultural waste releases CO2 and methane) or for farm animals (which release methane)
61
Q

Explain how the greenhouse effect is related to global heating.

A
  • energy from the Sun hits the Earth’s surface; some is absorbed and some is radiated back out
  • greenhouse gases in the atmosphere (including CO2 and methane) absorb much of this energy
  • this process heats the Earth
  • the heat retained by the Earth should be in equilibrium with the heat it emits (so that the planet is at a constant temperature)
  • but increasing levels of greenhouse gases have disrupted the balance, meaning earth is heating up - this is global heating.
62
Q

Describe 4 biological consequences of global heating.

A
  • Reduction in biodiversity, extinction (heating leads to changes in habitats)
  • Sea level rise (caused by expanding water and melting ice), leading to flooding and loss of habitats.
  • Changes in migration patterns (e.g. birds moving further North as it’s becoming warmer there)
  • Changes in distribution of species (global heating and the rainfall pattern changes it causes leads to some species thriving, as well as some having smaller ranges)
63
Q

Give 5 examples of programmes put in place to reduce the negative effects of humans on ecosystems and biodiversity.

A
  • breeding programmes for endangered species
  • protection and regeneration of rare habitats
  • reintroduction of field margins and hedgerows in agricultural areas where farmers grow only one type of crop
  • reduction of deforestation and CO2 emissions by some governments
  • recycling resources rather than dumping waste in landfill
64
Q

What is food security?

A

Having enough food to feed a population.

65
Q

Give 6 examples of factors which threaten food security.

A
  • population growth + aging populations
  • changing diets in developed countries means scarce food resources are exported away from local people
  • new pests and pathogens affect crops + animals
  • environmental changes affect food production, e.g. lack of rainfall causing widespread famine
  • agricultural input costs
  • armed conflicts affect availability of water or food
66
Q

Give 6 methods used to increase food security.

A
  • intensive farming (maximised yield)
  • machinery
  • pesticides
  • fertilisers
  • monocultures
  • feeding animals antibiotics
67
Q

In intensive farming, the efficiency of food production is improved by restricting energy transfer from food animals to the environment. Give 3 examples of how this is done.

A
  • limiting animals’ movement
  • heating their surroundings
  • some are fed high-protein diets to increase growth
68
Q

Intensive farming is a way of restricting energy transferred by animals to maximise yield. Give 3 advantages of this technique.

A
  • food quickly ready for consumption
  • meets high demand (more food per animal)
  • cost effective
69
Q

Intensive farming is a way of restricting energy transferred by animals to maximise yield. Give disadvantages of this technique.

A
  • disease spreads quickly (animals close together)
  • animals need constant monitoring (expensive)
  • ethics: animals have worse quality of life, restricted movement
70
Q

It is important to maintain fish stocks, which are currently declining, at a level where breeding continues. Give 2 examples of techniques used to conserve stocks at a sustainable level.

A
  • controlling net size and having larger holes (only adults caught; young fish can reproduce)
  • introducing fishing quotas
71
Q

Give 4 examples of modern biotechnology techniques which serve as solutions to the demands of the growing human population.

A
  • Mycoprotein production
  • GM bacteria used to produce insulin to treat diabetes
  • GM crops with more yield
  • GM crops with improved nutritional value, e.g. golden rice
72
Q

What is mycoprotein and how is it produced?

A
  • mycoprotein = a protein-rich food suitable for vegetarians
  • the fungus Fusarium is grown on glucose syrup, in aerobic conditions
  • the biomass is harvested and purified

Biology GCSE 2020 (7 decks)

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