SB9 Flashcards
What is community
All the organisms of different species living in a habitat
What is population
All the organisms of one species in a habitat
What is ecosystem
A community of organisms along with all the non-living conditions
Example of a community
All the living species in a forest
Example of a population
Deer’s in a forest
Example of an ecosystem
All the species and abiotic organisms in a forest
What is interdependence
When organisms depend on each other for things like food and shelter in order to survive and reproduce.
What is mutualism
A relationship between two organisms from which they both benefit.
What are abiotic factors and some examples
Non-living factors that affect communities such as temperature, amount of water, light intensity and levels of pollutants
What are biotic factors and some examples
Living factors that affect communities such as competition and predation
Explain how to estimate population size, including the use of quadrats.
Mean number of organisms per m^2 x area
You could use a belt transects calculate the change across a habitat or just use a quadrat.
Describe the energy transfers that occur between trophic levels.
The energy flows from one trophic level to the next after they are eaten.
Explain how energy is transferred at each trophic level, including making some energy less useful.
Energy decreases as it moves up trophic levels because energy is lost as metabolic heat when the organisms from one trophic level are consumed by organisms from the next level.
Explain how energy transfers limit the length of a food chain.
Each energy transfer is inefficient and looses energy each time therefor making it not sustainable.
Explain how energy transfers determine the shape of pyramids of biomass.
It shows how much the creatures at each level of a food chain would weigh if you put them together. Therefore showing how much energy there is at each stage.
Calculate the efficiency or biomass of energy transfer between trophic levels.
efficiency = energy or biomass transferred to next level / energy or biomass available at previous level x100
Explain how communities are affected by abiotic factors
It affects the distribution and population of a species
Describe how competition can affect communities
This can decrease a population that is unable to gain the resources
Describe how predation can affect
communities.
The prey of the predators might increase if the predators decrease
Explain how predator–prey cycles affect communities.
Predators with more prey.
Prey reduces when there are more predators.
Predators reduces when there is less prey
Explain how the structure of a community can affect biodiversity.
Community’s with higher biodiversity have fewer species that depend on just one other for food ect
What do stonefly larvae and freshwater shrimps show
It indicates the water is clean as they are sensitive to the concentration of dissolved oxygen
What do blood worms and sludge worms show
It indicates a very high level of water pollution as they have adapted to pollution conditions
What do some particular types of lichen show
Lots of lichen especially bushy lichen show good clean air as they are sensitive to the concentration of sulphur dioxide.
What do blackspot fungus show
Clean air as they are sensitive to the concentration of sulphur dioxide.
Advantages of using indicator species as evidence for the level of pollution
Cheap
Simple
Disadvantages of using indicator
species as evidence for the level of pollution.
May be other factors of pollution playing a role in the presence or absence of a species
Better to use non living indicators
Other ways to measure pollution
Dissolved oxygen metres
Electronic meters
What is parasitism
Parasitism is the relationship between a parasite and its host. The parasite benefits by gaining nutrients and/or energy from the host.
Describe how hosts are harmed by parasites
The host is harmed by losing energy and/or nutrients.
Examples of parasitism
Head and body lice are passed from people during physical contact
Fleas feed on dogs blood
Plasmodium (malaria) carried by mosquitoes from human to human
How do mutualists benefit from their relationship
Each was part of the other’s environment, so as they adapted to their environment, they “made use of” each other in a way that benefited both.
What is eutrophication
Eutrophication is a type of water pollution caused by the addition of sewage or fertiliser.
What is a non-indigenous species
A species that doesn’t naturally occur in an area
Example of how can non-indigenous species be introduced
Crayfish were introduced to the UK for food but they prey on and out-compete many indigenous species.
Advantages of fish farming
Fish cannot escape
Less transport costs
Protected from predators
Explain how fish farming can affect ecosystems and biodiversity
Can reduce biodiversity as predators can also be trapped in the nets and die
Explain how the introduction of species can affect ecosystems and biodiversity
They can reduce biodiversity as they can bring new diseases or out compete others
Explain how eutrophication can affect ecosystems and biodiversity.
Eutrophication can reduce the biodiversity as the fertiliser can lead to the death of many species in the water
What is conservation
Conservation is the preservation of ecosystems and the organisms that live within them.
What is reforestation
Planting trees to replace those cut down.
Give examples of animal conservation.
Breeding programs
Developing endangered habitats
Replanting hedgerows
Explain how animal conservation can benefit biodiversity.
Reduces damage to food chains and less likely to impact other species
Explain how reforestation can benefit biodiversity.
It can encourage the growth of new plants and therefore attract other animals to have habitats
What is food security
A measure of the availability of food required to support people of a household, region, country or any specified area.
Describe the effect of increasing human population on food security.
As population increases food security reduces
Describe the effect of new pests and pathogens on food security.
They reduce food security as they can attack farm animals
Describe the effect of animal farming and consumption on food security.
It is reduced as it wastes more energy because the food chain affected is longer. In addition, farmed animals are often fed crops which could be consumed by humans.
Describe the effect of human-induced environmental change on food security.
It makes farming more difficult in many areas reducing food security
Give examples of materials that cycle through ecosystems.
Water, carbon, nitrogen, sulphur and oxygen
Describe the processes by which water cycles through abiotic parts of an ecosystem.
Evaporation, condensation, transport, precipitation, surface runoff, infiltration, transpiration
What happens to the water during evaporation
Water turns from a liquid to a gas when it evaporates. Energy from the Sun can evaporate water from all places on the Earth’s surface such as puddles, ponds, lakes and oceans.
What happens to the water during condensation
After evaporation water can cool and convert from gas to liquid, often forming clouds.
What happens to the water during transport
Water within clouds can be blown many miles by strong winds and so transported to other areas.
What happens to the water during precipitation
Precipitation occurs when rain, snow, hail and sleet fall from the sky.
What happens to the water during surface runoff
Much water will be absorbed into the ground after precipitation but if a large volume falls or the ground is already wet some water can run along the surface of the ground.
What happens to the water during infiltration
This occurs when water that has fallen as precipitation is absorbed into the ground. This can then be stored within underground rocks called aquifers
What happens to the water during transpiration
Plants need to maintain a constant stream of water to their leaves for transport and support. They allow some water to evaporate as water vapour from their leaves so it is continually ‘pulled’ to their leaves from the soil.
Describe how drinking water is produced where water is plentiful.
Distillation or thermal desalination
Explain how drinking water can be produced by desalination in areas of drought.
Reverse osmosis:
1) salt water is forced at high pressure into a vessel with a partially permeable membrane
2) the pressure causes water molecules to move in the opposite direction to osmosis from a concentrated salt solution (low water concentration) to a lower salt concentration (higher water concentration)
3) water molecules pass across the membrane leaving the salt behind, so pure water is available for drinking
Examples of decomposers
Beetles, earthworms, millipede, mushroom
What are decomposers
Feed on dead and decaying organisms, and on the undigested parts of plant and animal matter in faeces.
Stages of the carbon cycle
1) Carbon enters the atmosphere as carbon dioxide from respiration and combustion.
2) Carbon dioxide is absorbed by producers to make carbohydrates in photosynthesis.
3) Animals feed on plants, passing the carbon compounds along the food chain. Most carbon they consume is exhaled as carbon dioxide during respiration. The animals and plants eventually die.
4) Dead organisms are eaten by decomposers and carbon in their bodies is returned to the atmosphere as carbon dioxide. In some conditions decomposition is blocked. The plant and animal material may then be available as fossil fuel in the future for combustion.
Identify the key processes in the carbon cycle.
Photosynthesis, respiration, combustion
Explain how carbon is cycled through the biotic and abiotic components of an ecosystem.
In the biotic cycle, it moves between living things and the air. In the abiotic cycle, it moves between the air, ground, and oceans
Explain the importance of the carbon cycle (in balancing photosynthesis and respiration, and removal of wastes by decomposition).
A balanced carbon cycle is essential as carbon is a major component in carbohydrates, fats and proteins.
Describe how plants use nitrates.
As a source of nitrogen preserving the amount of chlorophyll in leaves allowing the plant to grow
Roles of decomposers in the nitrogen cycle (type of bacteria)
Decompose proteins and urea and turn them into ammonia. Ammonia forms ammonium ions in solution that plants can use.
Roles of nitrifying bacteria in the nitrogen cycle (type of bacteria)
Turn ammonia in decaying matter into nitrites and then into nitrates. Different species of nitrifying bacteria are responsible for producing nitrites and nitrates
Roles of nitrogen-fixing bacteria in the nitrogen cycle (type of bacteria)
To turn atmospheric nitrogen into ammonia, which form ammonium ions.
Roles of denitrifying bacteria in the nitrogen cycle (type of bacteria)
To turn nitrates back into nitrogen gas. This is of no benefit to living organisms. This bacteria is often found in waterlogged soils
Explain how fertilisers increase the nitrate content of the soil.
It recycles the nutrients left in plant and animal waste and returns them to the soil through decomposition. Artificial fertilisers containing nitrates can also be used, but these can be expensive
Explain why bacteria are important for soil fertility.
Bacteria in the soil make an enzyme called urease which converts this urea into ammonia . Nitrifying bacteria convert the ammonia into nitrates which plants can now absorb.
Explain how crop rotation can increase the nitrogen content of the soil.
It helps to put nitrates back into the soil for another crop to use the following year.
What ways is food preserved
Storing in a fridge/freezer, storing in airtight cans, drying foods
Explain why food is preserved in different ways
To make all the different factors less suitable for microorganism’s survival and reproduction.
Describe how compost is made.
Produced from decomposed organic matter in warm, moist conditions with plenty of oxygen
Explain how the rate of decomposition in composting can be increased.
Can be increased by having mesh sides to increase oxygen availability and keeping the bins insulated
How to calculate the rate of decay in food and compost.
change in value / change in time
