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Biology > Ecology > Flashcards

Ecology Flashcards

1
Q

State the levels of organisation in an ecosystem

A

individual, population, community, ecosystem

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2
Q

What is an ecosystem?

A

the interaction between the living and non-living components

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3
Q

State the factors that plants may compete for

A
  • light
  • space
  • water
  • mineral ions from soil
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4
Q

State the factors that animals might compete for

A
  • food
  • mates
  • territory
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5
Q

What is intraspecific competition?

A

competition within a species

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6
Q

What is interspecific competition?

A

competition between different species

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7
Q

What is interdependence?

A

different species in a ecosytem depend on each other various resources, if one species is removed, the whole community may be affected

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8
Q

What is a stable community?

A

a community in which all the biotic factors (the different species) and all abiotic factors are balanced so that population sizes remain relatively constant

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9
Q

What are abiotic factors?

A

non-living factors

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10
Q

State the abiotic factors that may affect an ecosystem

A
  • light intensity
  • temperature
  • moisture
  • soil pH and mineral content
  • wind intensity and direction
  • carbon dioxide level
  • oxygen level
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11
Q

Why might light intensity affect an ecosystem?

A

different species of plants may have different optimum light intensites for growth

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12
Q

Why does temperature affect an ecosystem?

A

different species of plants and animals may have different optimum temperatures for growth and survival

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13
Q

How does soil pH affect an ecosystem?

A

certain plants may grow better in either alkaline or acidic soil, soil pH may affect the appearance of the plant, e.g. colour of hydrangea

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14
Q

How does moisture level affect an ecosystem?

A

many plants cannot survive in waterlogged soil as their roots cannot respire, certain plants are adapted to high moisture levels

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15
Q

How does wind intensity affect an ecosystem?

A

plant seeds are more likely to germinate in locations with lower wind intensity, which may also attract animals that depend on the plant to live nearby

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16
Q

How does soil mineral content affect an ecosystem?

A

most plants require a high level of soil minerals to grow well

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17
Q

Give an example of a type of plant that have adapted to a low soil mineral content

A

carnivorous plants catch insects to compensate for the low level of soil mineral content

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18
Q

How does carbon dioxide concentration affect an ecosystem?

A

higher carbon dioxide concentration leads to more plant growth

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19
Q

How does oxygen concentration affect an ecosystem?

A

aquatic animals cannot survive in areas with low oxygen concentration

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20
Q

State the biotic factors that may affect an ecosystem

A
  • food
  • new predators
  • new pathogens
  • competition
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21
Q

What are adaptations?

A

features that enable organisms to survive in their living environment

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22
Q

What are organisms living in extreme envrionments called?

A

extremophiles

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23
Q

Give 3 examples of extreme living environments

A
  • high temperature
  • high pressure
  • high salt concentration
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24
Q

State an example of where extremophile bacteria can be found

A

in deep sea vents

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25
Q

Define population

A

a species that occupy the same habitat

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26
Q

Define habitat

A

the place in which can organism lives

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27
Q

Define community

A

populations of different species interacting

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28
Q

Define ecosystem

A

the interactions between the biotic and abiotic factors in an area

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29
Q

What do food chains show?

A

food chains show the feeding relationships of different organism and the flow of energy between the organisms

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30
Q

Define biomass

A

the total mass of living material

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31
Q

What are trophic levels?

A

the stages in a food chain

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32
Q

What do arrows in a food chain represent?

A

the direction of biomass transfer

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33
Q

Describe a simple food chain

A

producer –> primary consumer –> secondary consumer –> tertiary consumer

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34
Q

What is a producer?

A

an organism that makes its own food

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35
Q

What types of organisms are primary producers?

A

photosynthetic organisms like green plants and algae that trap energy from the sun

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36
Q

What is a primary consumer?

A

an organism that feeds on producers

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37
Q

What is a secondary consumer?

A

an organism that feeds on primary consumers

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38
Q

What is a tertiary consumer?

A

an organism that feeds on secondary consumers

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39
Q

What is a predator?

A

a consumer that kills and eats other animals

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40
Q

What is prey?

A

an animal that is killed an eaten by another animal

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41
Q

Describe the pattern of predators and prey in a stable community

A

the numbers of predators and prey rise and fall in cycles

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42
Q

Why are producers the first trophic level?

A
  • producers provide all biomass for the food chain (production of glucose via photosynthesis)
  • the rest of the food chain involves the transfer of this biomass
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43
Q

What piece of apparatus is used to measure the abundance and distribution of organisms in an area?

A

quadrat

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44
Q

What piece of apparatus is used to study the distribution of organisms across a gradient?

A

bell transect

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45
Q

When considering the abundance of organisms, what is meant by the term ‘mean’?

A

the average number of organisms

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46
Q

How is the arithmetic mean calculated?

A

sum of each number of each organism/the total number of each type of organism

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47
Q

When considering the abundance of different organisms, what is meant by the term ‘mode’?

A

the most populous organism

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48
Q

When considering the abundance of organisms, what is meant by the term median?

A

the organism that represents the middle value when the numbers of each organism are arranged from lowest to highest

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49
Q

Describe how materials cycle through the living and non-living components of an ecosystem

A
  • organisms take in elements from their surroundings e.g. soil, air
  • elements converted to complex molecules which become biomass
  • elements transferred along food chains
  • elements returned to environment during excretion and decompostition of dead organisms
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50
Q

Give 3 molecules which are cycled through ecosystems

A

oxygen, carbon dioxide and water

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51
Q

Describe the carbon cycle

A
  • plants fix carbon dioxide into organic molecules during photosynthesis
  • the organic carbon-containing molecules are passed onto organisms that eat the plants
  • carbon dioxide is released back into the atmosphere by respiration from animals and plants
  • burning fossil fuels also released carbon dioxide into the atmosphere
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52
Q

Why is the carbon cycle so important?

A

carbon-containing molecules such as glucose are important for living organisms to grow and provide energy for vital functions within cells

53
Q

Describe the water cycle

A
  • water from lakes and oceans evaporates
  • the evaporated water condenses into clouds and returns to earth as precipitation
  • the water from precipitation is useful for life on land
  • the water then returns to rivers and oceans through surface runoff
54
Q

Why is the water cycle important?

A

living organisms require water and the water cycle provides organisms on land with a continuous supply of water

55
Q

Why are microorganisms important for the cycling of materials through an ecosystem?

A

microorganisms (bacteria and fungi) return carbon to the envrionment by releasing carbon dioxide through respiration while they decompose dead matter. the decomposition of dead matter in soil returns mineral ions to the environment for other organisms to use e.g. plants use mineral ions for growth

56
Q

What is meant by decomposition?

A

the breakdown of dead materials into simpler organic matter

57
Q

How do decomposers break down dead matter?

A

decomposers release enzymes which catalyse the breakdown of dead material into smaller molecules

58
Q

What are the 2 types of decomposition?

A

aerobic decomposition (with oxygen) and anaerobic decomposition (without oxygen)

59
Q

What factors affect the rate of decomposition?

A
  • oxygen availability
  • temperature
  • water content
60
Q

Why is oxygen required for decomposition?

A

most decomposers require oxygen for aerobic respiration

61
Q

How does the availability of oxygen affect the rate of decomposition?

A
  • as oxygen levels increase, the rate of decomposition increases
  • as oxygen levels decrease, the rate of decomposition decreases
62
Q

Why can decomposition still occur in the absence of oxygen?

A

some decomposers respire anaerobically
*however, the rate of decomposition is slower as anaerobic respiration produces less energy

63
Q

How does soil water content affect the rate of decomposition?

A

decomposers require water to survive:
- in moist conditions the rate of decomposition is high
- in waterlogged soils there is little oxygen for respiration so the rate of decomposition decreases

64
Q

Why does decomposition require water?

A

water is required for the secretion of enzymes and absorption of dissolved molecules

65
Q

How does temperature affect the rate of decomposition?

A

decomposers release enzymes:
- rate highest at 50 celcius (optimum temp for enzymes)
- lower temperatures, enzymes work too slowly, rate decreases
- high temperatures, enzymes denature, decomposition stops

66
Q

How is the rate of change calculated when considering the decay of biological material?

A

rate of change = change in value/change in time
where value is a measurable variable associated with the decay of the material

67
Q

What is compost?

A

the nutrient-rich product of the rapid decay of waste biological material (dead plants and animal waste) in optimum conditions set by gardeners and farmers

68
Q

How is compost used?

A

used as natural fertiliser to promote growth of crops or garden plants

69
Q

Describe how biogas generators work

A

biogas generators provide methane gas for fuel through anaerobic decomposition that occurs in animal waste

70
Q

Describe how environmental conditions affect communities

A
  • environmental conditions e.g. temperature, soil pH, light intensity affect the abundance and distribution of organisms within communities
  • e.g. rising global temperatures have been linked to the extinction of frog species (their thin skin makes them more vunerable to temperature changes)
71
Q

How can different temperatures be bad for certain commuities?

A
  • if the temperature is too low, growth will be slower as organisms will use more energy to stay warm
  • if the temperature is too high, organisms can die and water will become limited as evaporation increases
72
Q

How can changes in water levels affect ecosystems?

A
  • animals may have to migrate to find water
  • melting ice caps may destroy the habitats of some animals (either animals living in icy regions or by sea level rise)
73
Q

How can atmospheric gases affect ecosystems?

A
  • some organisms cannot survive when certain gases are present
  • polluted water can cause illness to animals that drink it
74
Q

What detrimental impacts can sulfur dioxide have on the environment?

A
  • formed when fossil fuels containing impurities are burnt
  • sulfur dioxide can dissolve in water to form acid rain which can erode buildings and pollute water sources
75
Q

What detrimental impacts can carbon monoxide have on the environment?

A
  • carbon monoxide is formed from the incomplete combustion of fossil fuels
  • carbon monoxide binds irreversibly to haemoglobin which prevents it from carrying oxygen
  • too much exposure can cause unconsciousness and death
76
Q

Name 5 greenhouse gases

A
  • water vapour
  • carbon dioxide
  • nitrous oxide
  • methane
  • CFCs
77
Q

Give 3 human activities that contribute to greenhouse gases

A
  • burning fossil fuels
  • deforestation
  • large scale livestock farming
78
Q

How do greenhouse gases lead to global warming?

A
  • greenhouse gases allow heat from the sun to enter the atmosphere
  • the gases act as a ‘blanket’ and trap the heat in the atmosphere
79
Q

State 3 negative consequences of global warming

A
  • sea level rise caused by melting icebergs
  • disrupted farming and agriculture
  • increased spread of diseases in warmer climates
80
Q

What is biodiversity?

A

the variety of the different species on earth or within an ecosystem

81
Q

What is the importance of biodiversity?

A

to maintain the stability of an ecosystem

82
Q

How does biodiversity ensure the stability of an ecosystem?

A

it reduces the dependence on particular species for resources e.g. food and shelter, so that even if one species is removed other species can still survive

83
Q

Why have humans’ consumption of resources and waste production increased?

A
  • rapid rise in human population
  • increase in standard of living
84
Q

Where does pollution occur?

A
  • air
  • land
  • water
85
Q

State 3 examples of water pollutants

A
  • sewage
  • fertiliser
  • chemicals
86
Q

How does eutrophication occur?

A

feriliser from farms pollute the water, causing excessive algae growth, depleting the oxygen in the water, causing other plants and animals to die
dead plants are decomposed by bacteria and the oxygen level decreases further

87
Q

State an example of air pollutants

A
  • smoke
  • acidic gases
87
Q

State an example of land pollutants

A
  • landfill waste
  • chemicals
88
Q

Which human activities reduce the land available for animals and plants?

A
  • building
  • farming
  • quarrying
  • disposing of waste
89
Q

Why have peat bogs been destroyed?

A

to produce compost to increase food production

90
Q

Why does the destruction of peat bogs greatly contribute to the greenhouse effect?

A

peat bogs are stores of carbon (carbon sinks) and burning them releases a large volume of carbon dioxide into the atmosphere

91
Q

Why have large-scale deforestation activities occurred?

A
  • to provide land for cattle or rice fields
  • to grow crops to produce biofuels
92
Q

What is the greenhouse effect?

A

greenhouse gases trap energy from the sun as heat in the atmosphere, keeping the temperature on earth suitable for life

93
Q

What is causing global warming?

A

the increase in levels of greenhouse gases e.g. carbon dioxide and methane, causing the temperature on earth to increase

94
Q

What are the harmful effects of deforestation?

A
  • destruction of many animals’ habitats
  • releases large amounts of greenhouse gases
95
Q

State the consequences of global warming

A
  • rising sea levels
  • melting polar ice caps
  • changing weather patterns
  • migration of animals to find suitable habitats
  • tropical diseases becoming more common
  • extinction of species
96
Q

Describe the steps taken to maintain biodiversity

A
  • breeding programs for endangered species
  • protection and rebuilding habitats
  • replanting field margins and hedgerows
  • reduce deforestation
  • reduce carbon dioxide emissions
  • recycling rather than disposing in landfills
97
Q

What is the purpose of replanting hedgerows and field margins?

A

there is higher biodiversity in the margins than the fields the surround

98
Q

What does a food chain show?

A

it describes the feeding relationships between organisms and the resultant stages of biomass transfer

99
Q

What are trophic levels?

A

the stages in a food chain

100
Q

How are trophic levels represented?

A

trophic levels are represented by numbers, starting from 1. after 1, trophic levels are numbered according to how far along the organism is in the food chain

101
Q

What is trophic level 1?

A

plants and algae which make their own food (through photosynthesis) - called producers

102
Q

What is trophic level 2?

A

herbivores which eat producers - called primary consumers

103
Q

What is trophic level 3?

A

carnivores that eat herbivores - called secondary consumers

103
Q

What is trophic level 4?

A

carnivores that eat other carnivores - called tertiary consumers

104
Q

What is an apex predator?

A

a carnivore with no predators

104
Q

How do decomposers break down dead matter?

A

decomposers release enzymes which catalyse the breakdown of dead material into smaller molecules, soluble small food molecules then diffuse into the microorganisms

104
Q

What is biomass?

A

the dry mass of all the living organisms in an area

104
Q

Why is dry mass used for biomass?

A

because the wet mass varies as the volume of water in the organism varies

104
Q

How do you calculate the efficiency of biomass transfer?

A

efficiency = (energy transferred / otla energy available) x 100

104
Q

What percentage of the incident energy from light for photosynthesis do producers transfer?

A

1%

104
Q

What percentage of the biomass from one trophic level is transferred to the level above it in feeding?

A

approximately 10%

104
Q

Why are biomass transfers not 100% efficient?

A

energy is lost through:
- egestion (removal of faeces)
- excretion (removal of waste production e.g. urine containing urea and water)
- respiration (loss of carbon dioxide and water) in which large amounts of glucose are used
- the production of inedible bones and shells

104
Q

How does the efficiency of biomass transfers affect the number of trophic levels in a biomass pyramid?

A

the less efficient the transfers, the fewer trophic levels and the fewer organisms in higher trophic levels

104
Q

What is a biomass pyramid?

A

a pyramid that shows the total dry mass of organisms at each trophic level
trophic level 1 is at the bottom of the pyramid

104
Q

What is a pyramid of numbers?

A

a pyramid of numbers shows the number of organisms at each trophic level

104
Q

Why are pyramid of numbers not always pyramid shaped?

A

pyramids of numbers don’t take size and mass of organisms into account

104
Q

What is food security?

A

having enough food to be able to feed a population

104
Q

State the biological factors threatening food security

A
  • rising birth rates
  • changing diets in developed countries –> food is transported around the world
  • new pests and pathogens
  • environmental changes affecting food production
  • increased cost of agriculture
  • armed conflicts
104
Q

How does intensive farming increase the production of animals?

A
  • feed animals high protein foods to increase growth
  • reduce their energy loss to environment by limiting movement and regulating their surrounding temperature
  • feed animals antibiotics to prevent diseases
104
Q

What are the advantages of intensive farming?

A
  • higher yield of food
  • more efficient
  • allows easier quality control
104
Q

What are the disadvantages of intensive farming?

A
  • may lead to antibiotic resistance
  • cost is high
  • ethical objections e.g. limiting movement of animals may cause them harm
  • biodiversity may be reduced
104
Q

How can fish stocks be conserved?

A
  • control the size of gaps in fishing nets to prevent juvenile fish from being killed before reaching reproductive maturity
  • introduce fishing quotas
104
Q

What is a transgenic organism?

A

an organism that has been genetically modified to contain genetic material from another source

104
Q

State an example of genetically modified foods

A

golden rice

104
Q

How might crops be genetically modified?

A
  • to improve nutritional value
  • to be pest resistant
  • to be pesticide resistant
104
Q

What are the advantages of golden rice?

A

it contains addition beta-carotene which can be converted to vitamin A in the body, supplementing people who do not obtain enough vitamin A in their diet to prevent night blindness from forming

104
Q

What is mycoprotein?

A

a protein-rich substance used to make meat substitute food for vegetarians and vegans

104
Q

How is mycoprotein produced?

A

fusarium, a fungus, is grown on glucose syrup, in aerobic conditions and the biomass is harvested and purified to get the mycoprotein

Biology (7 decks)

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