4 markers Flashcards
Four factors that make use of the insecticide DDT controversial (4 marks)
- very effective and affordable
- can control agricultural pests and improve harvest
- but has negative effects on human health
- can bioaccumulate in organisms
Outline one method for measuring the impact of a build-up of dead organic matter in an aquatic ecosystem (4 marks)
- use a biotic index which is based on species tolerance, diversity and relative abundance
- identify number of species and count number of individuals
- calculate diversity index for samples
- presence of indicator species will indicate whether water is clean/unpolluted
- impact is judged by changes in diversity over a range of time or space
outline the albedo effect and its role in regulating the Earth’s global temperature (4 marks)
- albedo is measure of reflectiveness of a surface
- high albedo means a surface is very reflective and reflects a lot of solar insolation- the opposite is true for a dull surface with low albedo
- high albedo results in a negative feedback loop where rise of temp, increased evaporation, increased cloud cover, increases albedo and reflection of insolation, reducing global temperatures
- but change in albedo balance can lead to positive feedback loops where rise in global temp, increase melting in ice caps, decrease in albedo which increases solar radiation absorption
Four strategies that can be used in the sustainable management of wild fisheries (4 marks)
- use of quotas/international regulations on fishing, especially of endangered species
- create marine protected areas to restrict fishing in some areas
- develop aquaculture industries so farm fish rather than catch wild fish
- campaigns to reduce consumption of wild fish
Outline the processes by which a species may evolve a greater tolerance to higher temperatures (4 marks)
- a species will have a variety of their own characteristics in their genes
- some genes may provide greater tolerance to higher temperatures than others (mutations may also cause this)
- Individuals with these genes are more likely to survive in the high temperatures so they outcompete the intolerant
- over time tolerance of high temperatures become a dominant characteristic in population
Outline the procedures in a laboratory-based method to find the gross productivity for a population of named aquatic animals in terms of biomass per day (4 marks)
- find the dry weight of food presented to the population at start
- collect and find the dry weight of food remaining after a number of days
- subtract the weight of food remaining from that presented
- collect and find the dry weight of faeces produced over this period
- subtract weight of faeces from food eaten to find food absorbed = gross productivity
- divide gross productivity by number of days of the study;
With reference to four different properties of a soil, outline how each can contribute to high primary productivity (4 marks)
- particle size of soil affects ability of soil to store water for productivity
- air spaces provide more space for roots to penetrate soil so more growth
- neutral to slightly acidic pH is optimal for plant growth
- low or no slope prevents water erosion and loss of soil
Identify four ways to ensure reliability of the mark–release–recapture method in estimating population size (4 marks)
- ensure the capture process does not reduce potential for recapture (more scared)
- ensure marking process doesn’t impact individuals survival
- ensure marking is durable and lasts for length of investigation
- ensure sufficient time between captures to allow mixing of population
Distinguish between two named biomes and the factors that cause their distribution (4 marks)
- Tundra has lower insolation than tropical rainforest which has highest insolation. This is because Tundra is found at the poles while TRF is found at tropics
- TRF is biome with most precipitation and tundra has least because Hadley cell rises at equator causing huge precipitation whereas Tundra in in low pressure area of polar cell
- TRF high biodiversity due to favourable warmer climate whereas Tundra has opposite
Explain how a positive feedback loop can impact an ecosystem (4 marks)
- Positive feedback loops amplify changes in an ecosystem
- This causes a system to be pushed to a tipping point where a new equilibrium is adopted
- for example increased global temperatures are melting permafrost, leading to the release of methane
- Methane is a greenhouse gas and leads to further increases in global temperatures
Outline two factors that enable a human population to increase its local carrying capacity (4 marks)
- variations in lifestyle
- means people can be flexible in their types of consumption of limited resources, eg shifting away from beef
- technological developments
- means humans may be able to make resources more efficient
Outline two factors that affect the frequency and severity of photochemical smog in an area (4 marks)
- High population density areas have more traffic
- this increases the concentration of the primary pollutant
- topographic factors like hills/mountains
- these can result in trapping the pollutants because wind is blocked eg LA
Outline, using examples, the differences between primary and secondary pollution (4 marks)
- Primary pollution is active upon emission of the pollutant
- e.g carbon dioxide
- Secondary pollution occurs when primary pollutants undergo a physical or chemical change
- eg sulphur oxide forms with water to make acid rain
Outline the factors that contribute to total biodiversity of an ecosystem (4 marks)
- biodiversity includes the diversity of species, habitat and genes
- species diversity contributes through species richness and evenness
- habitat diversity contributes and refers to range of different habitats in an ecosystem
- gene diversity contributes and refers to range of genes in a population
- high precipitation and optimum growth conditions for primary producers supports biodiversity
Outline how energy drives the hydrological cycle (4 marks)
- primary source of energy driving hydrological cycle is solar energy
- solar energy causes changes of state in water e.g evaporation
- solar energy causes the temperature differences that create winds which move water vapour in the air
- solar energy melts ice producing streams lakes
Outline how the concept of sustainability can be applied to managing natural capital (4 marks)
- natural capital refers to natural resources that can supply a natural income of goods or services
- natural income is the yield made from the natural capital
- to be sustainable, natural capital has to be used slower than its replenishment so future needs aren’t compromised
- Realising that extracting more than the natural income is unsustainable means humans can be informed through education to make changes, potentially through policies and legislations
With reference to processes occurring within the atmospheric system identify two transformations of matter (4 marks)
- evaporation
- condensation
Identify four factors that make the estimation of carrying capacity more problematic for human populations than for most other species (4 marks)
- humans can import resources from different locations
- humans can substitute the resources they use easily
- different human populations live varying and different lifestyles so carrying capacities are not uniform
- humans produce a lot of waste which damages the environment and can reduce carrying capacity
Identify four strategies for limiting the impact of burning fossil fuels without reducing their use (4 marks)
- use of scrubbers on factories and power plants
- use low sulphur coal resources
- carbon sequestration
- afforestation or reduce deforestation
Identify four impacts on an ecosystem that may result from the introduction of an invasive species of herbivore (4 marks)
- reduction in plant species because of herbivore feeding
- causing reduction in overall productivity
- native herbivore species get outcompeted
- which reduces overall species diversity
Outline two ecosystem services in a named biome (4 marks)
Wetland biome
- the storage of water in wetland
- acts as natural flood defence
- decomposers in the wetland
- purify the water
Outline how four different factors influence the resilience of an ecosystem (4 marks)
- greater diversity of species increases resilience
- increased complexity within food webs increase resilience
- strong negative feedback loop increases resilience
- strong positive feedback loops can decrease resilience
Distinguish between the terms niche and habitat with reference to a named species (4 marks)
- habitat is the kind of environment in which a species normally lives
- eg lions are found in tropical grasslands
- niche is all the interactions between a species and it’s environment
- eg the prey that lions feed off
Outline the factors that lead to different environmental value systems in contrasting cultures (4 marks)
- religious factor
- some religions place a high value on nature and so have a more ecocentric EVS- eg Hindu religion deify cows
- economic factors
- a more economically wealthy society, such as certain societies within the HIC of USA, may tend toward a more technocentric EVS
