Ecology Flashcards
Paper 2 - B7
In an ecosystem, what is the difference between a population and a community?
A population is a group of organisms of the same species. A community is a group of populations (different species)
What do Plants compete for?
Light, space, minerals, water
What do Animals compete for?
Food, territory, mates (within a species only)
What name is given to the a) living and b) non-living parts of an ecosystem?
a) biotic b) abiotic
What is an ecosystem?
The interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment
List the ways in which one organism might depend on another within an ecosystem (interdependence)
Food, shelter, pollination, seed dispersal
What are some abiotic factors which might affect a
community of organisms?
light intensity; temperature; moisture levels; soil pH & mineral content; wind intensity & direction; carbon dioxide levels (plants only); oxygen levels (aquatic animals)
What are some biotic factors which might affect a
community of organisms?
availability of food; new predators arriving; new pathogens; one species outcompeting another so that there are not enough individuals to breed
What is an Adaptation?
Special features an organism has to enable it to be successful within its environment
What are the 3 different categories of adaptation which enable an organism to be successful within its environment?
Behavioural, structural, functional
What are extremophiles?
Organisms that can live in extreme environments such as high temperature, pressure or salt concentration
Where might you find extremophiles in the ocean?
In deep sea vents
What are the producers of biomass for all life on earth?
Photosynthetic organisms (including plants)
How can we represent feeding relationships within a community?
Food chains or webs
What organisms are at the start of all food chains?
Photosynthetic organisms such as plants or algae
What is a Quadrat?
A piece of equipment that can be used to estimate percentage cover of plants in an ecosystem
What is the Transect Line?
The line along which quadrats can be placed to investigate the distribution of plants within an ecosystem
What is meant by the terms ‘distribution’ and ‘abundance’ when studying organisms within an ecosystem
-How the organisms are spread out within the ecosystem
-How many there are
In a food chain, name the first trophic level
Producers
Name the trophic level in a food chain that feeds on producers
Primary consumers
Name the third trophic level in a food chain
Secondary consumers
Name the fourth trophic level in a food chain
Tertiary consumers
What name is given to a consumer that kills and eats other animals?
A predator
What name is given to an animal that is eaten by another animal?
Prey
Why do the population numbers of predators and prey rise and fall in cycles?
When prey numbers are high, there is lots of food for the predators, but this means more predators so more prey are eaten.
In the carbon cycle, what is the only way in which carbon dioxide can be removed from the air and turned into other carbon compounds?
By plants in photosynthesis
In the water cycle, name the process by which water from the ground is returned to the air
Evaporation
In the water cycle, name the process by which water vapour is converted to a form that plants and animals can use
Precipitation
In the carbon cycle, how is the carbon in dead organisms recycled?
Microorganisms decompose the organism, respire and return carbon dioxide to the air
Aside from recycling carbon, what other important role do microorganisms play in decomposition?
Returning mineral ions to the soil
(Triple only) Give 3 factors that affect the rate of decay of biological material
Temperature, water availability, oxygen availability
(Triple only) What is compost?
Substance produced by decay of waste biological material that can then be used as a natural fertiliser for growing garden plants or crops
(Triple only) What is produced by anaerobic decay of waste biological material?
Methane
(Triple only) What is biogas?
A fuel containing methane produced by anaerobic decay in biogas generators
(Triple only) Give 3 environmental changes that can affect the distribution of species in an ecosystem
Temperature; availability of water; composition of atmospheric gases
What is biodiversity?
The variety of all the different species of organisms on earth or within an ecosystem
How does high biodiversity make an ecosystem more stable?
By reducing dependence of one species on another for food, shelter
What effect are humans having on biodiversity and why is this a problem?
Reducing it; means less available for future use
What are the two effects of an increasing human population and increased living standard?
More resources are used; more waste is produced
How can pollution occur in water?
Sewage, fertiliser or toxic chemicals
How can pollution occur in air?
Smoke and acidic gases
How can pollution occur on land?
Landfill and toxic chemicals
Why is pollution a problem?
Kills plants and animals and reduces biodiversity
Give 4 ways in which humans can reduce the amount of land available for other animals
Building; quarrying; farming; dumping waste
Which habitat is being destroyed to produce garden compost?
Peat bogs
What two problems are being caused by the destruction of peat bogs?
Reduces biodiversity; burning/decay of peat releases carbon dioxide into the atmosphere which leads to global warming
Give two reasons why large scale deforestation is being carried out
To provide land for cattle and rice fields; to grow crops for biofuels
Name two greenhouse gases
Carbon dioxide and methane
List 3 consequences of global warming
Sea level rise; ice caps melting; habitat destruction; extinction; changes to animal behaviour or distribution
What can farmers do to increase biodiversity in fields where they only grow one type of crop?
Reintroduce field margins and hedgerows
What can humans do to reduce the amount of waste in landfill?
Recycling resources
How can humans help to protect endangered species?
Breeding programmes
How can humans help to reduce destruction of rare habitats?
Protection (e.g. laws, nature reserves) and regeneration
How can governments help to reduce global warming?
Reduction of deforestation and carbon dioxide
emissions
(Triple only) What name is given to carnivores with no predators?
Apex predators
(Triple only) How do decomposers break down dead plant and organic matter?
They secrete enzymes into the environment. Small soluble molecules then diffuse into the microorganism
(Triple only) How can we visually represent the relative amount of biomass in each level of a food chain?
Pyramids of biomass
(Triple only) What is represented by each ‘bar’ on a pyramid of biomass?
The total dry mass of all organisms within a trophic level (average dry mass of one organism x total number of organisms)
(Triple only) How is biomass lost between each trophic level in a food chain?
Not all ingested material is absorbed - some egested as faeces; some lost as waste e.g. carbon dioxide and water in respiration; water and urea in urine; glucose used in respiration
(Triple only) How do we calculate efficiency of biomass transfers between trophic levels?
% efficiency = biomass available to next level/biomass entering level x 100
(Triple only) What is food security?
Having enough food to feed a population
(Triple only) What is sustainable food production?
Production of sufficient resources for the population, with minimal impact on the environment and/or leaving enough for the population to recover
(Triple only) What are the factors that affect food
security?
Increasing birth rate in some countries; changing diets in developed countries; new pests/pathogens; environmental changes e.g. rains fail = famine; cost of agricultural inputs;
conflict
(Triple only) How does intensive farming increase efficiency of food production?
Restricts energy transfer from food animals to environment
(Triple only) Give 2 ways in which energy transfer from food animals to the environment can be reduced in intensive farming
Limiting movement; controlling temperature of surroundings
(Triple only) What can be supplemented in animal feed to increase growth?
Protein
(Triple only) Why is there currently a need for sustainable fishing methods?
Fish stocks in oceans are declining. If they are too low, breeding cannot continue and species could disappear completely from certain areas
(Triple only) Give two ways in which fish stocks can be kept at a sustainable level
Control of net size (smaller nets, larger holes) and introduction of fishing quotas
(Triple only) How can genetic modification help meet the food demands of a growing human population?
Genes can be altered to increase crop yield and quality
(Triple only) What is mycoprotein?
A protein-rich food produced by Fusarium fungus, suitable for vegetarians
(Triple only) Name the fungus that produces mycoprotein
Fusarium
(Triple only) What conditions are needed to produce mycoprotein?
Glucose syrup growth medium; aerobic conditions
(Triple only) How can scientists grow HUMAN insulin to treat diabetes?
Genetically modified bacteria (alternative is to use animal insulin which is not the same and may have issues for people who object to use of animal products)
(Triple only) What is golden rice?
Rice genetically modified to be high in beta-carotene which is needed to make vitamin A
