The living environment
50 exam-style questions with answers for 3.1 The living environment in AQA A-level Environmental Science (spec 7447). Practise with flashcards, a topic quiz, a random quiz across the course, 5 crosswords, Five Degrees, Associations, or read every question and answer below. Not official AQA material.
All 50 questions and answers
Question 1
Define the term ‘biome’. [1 mark]
Answer:A large geographical region with particular climatic features and a unique community of vegetation and wildlife.Question 2
Explain why keystone species are a conservation priority. [2 marks]
Answer:Their survival is important for the survival of many other species. Losing one causes knock-on effects through food webs and interspecies relationships.Question 3
Describe how plagioclimax habitats are maintained. [2 marks]
Answer:Human activity stops succession reaching the climax community, for example by grazing, mowing, burning, coppicing or pollarding.Question 4
Define the term ‘species’. [1 mark]
Answer:A group of organisms that resemble each other more than others and interbreed to produce fertile offspring.Question 5
Define the term ‘ecological niche’. [1 mark]
Answer:The role an organism plays in its habitat: its use of resources and its relationships with other species.Question 6
Define the term ‘community’. [1 mark]
Answer:The populations of all the species living in a particular area.Question 7
State what is meant by an ‘endemic’ species. [1 mark]
Answer:A species found within a single area only.Question 8
State two ways humans directly exploit wildlife. [2 marks]
Answer:Any two from: food, fashion, traditional medicines, pets, entertainment or sport.Question 9
Describe how CITES protects endangered species. [3 marks]
Answer:It bans or restricts international trade in listed species, with fines or imprisonment, so people are less likely to take wild individuals. Appendix I is the strictest.Question 10
Describe how ‘Debt for Nature Swaps’ help conserve biodiversity. [1 mark]
Answer:A country’s debt is cancelled or reduced in exchange for it protecting its rainforest.Question 11
Explain how a biological corridor may increase a population. [2 marks]
Answer:It links habitats so individuals can reach more breeding sites, partners and food, increasing gene flow.Question 12
Explain how mangroves benefit coral reefs. [2 marks]
Answer:They trap sediment, reducing turbidity so light reaches coral for photosynthesis, and act as nursery grounds for reef fish.Question 13
Describe how eDNA is used to monitor species. [2 marks]
Answer:A water sample is analysed for DNA shed by organisms, identifying species present without seeing or trapping them.Question 14
Distinguish between soft and hard release. [2 marks]
Answer:Soft release: animals are given food, shelter and support after release. Hard release: animals are released with no support.Question 15
Explain why captive-bred animals may struggle after release. [2 marks]
Answer:They may lack foraging skills, predator recognition and immunity to local disease.Question 16
Define the term ‘ecosystem’. [1 mark]
Answer:A community of organisms interacting with each other and with their physical environment.Question 17
Define the term ‘population’. [1 mark]
Answer:All the individuals of a species living in a particular area.Question 18
Define the term ‘carrying capacity’. [1 mark]
Answer:The maximum population an environment can support sustainably.Question 19
Define the term ‘rewilding’. [1 mark]
Answer:Management that allows a habitat to re-establish natural processes and biodiversity.Question 20
Define the term ‘EDGE species’. [1 mark]
Answer:Evolutionarily Distinct and Globally Endangered: a threatened species that diverged long ago, so has large genetic differences from other taxa.Question 21
Describe the role of a flagship species. [1 mark]
Answer:A species with a high public profile that raises awareness and funding for conservation.Question 22
State two reasons to conserve biodiversity. [2 marks]
Answer:Any two from: timber, new medicines, biomimicry, genetic resources for crops, ecosystem services.Question 23
Explain why wild relatives of crops should be conserved. [2 marks]
Answer:They contain genes, for example for pest or drought resistance, that could improve cultivated crops.Question 24
Explain how habitat fragmentation harms a population. [3 marks]
Answer:Isolated populations have smaller gene pools, more inbreeding and difficulty recolonising areas.Question 25
Describe how a Site of Special Scientific Interest (SSSI) protects wildlife. [2 marks]
Answer:Legal designation restricts damaging activities and requires management plans.Question 26
Explain how oxygen was first produced on Earth. [3 marks]
Answer:Photosynthetic bacteria, then algae and plants, released oxygen. Some formed ozone in the stratosphere, which absorbs UV.Question 27
State one way the magnetosphere protects life. [1 mark]
Answer:Its magnetic field deflects solar radiation (the solar wind).Question 28
Explain why r-selected species recover quickly after culling. [2 marks]
Answer:High fecundity and early maturity let populations increase rapidly.Question 29
Describe the stages of succession on bare rock. [4 marks]
Answer:Pioneer lichens and mosses weather rock and add organic matter. Grasses, shrubs and trees then colonise, ending in a climax community.Question 30
Distinguish between density-dependent and density-independent factors. [2 marks]
Answer:Density-dependent factors, such as competition and disease, act more strongly as population rises. Density-independent factors, such as severe weather, do not.Question 31
Define the term ‘habitat’. [1 mark]
Answer:The place where an organism, population or species lives, providing its food, shelter and other needs.Question 32
Define the term ‘biodiversity’. [1 mark]
Answer:The variety of life, including the number and variety of species, genetic diversity within species and the variety of habitats and ecosystems.Question 33
Define the term ‘genetic diversity’. [1 mark]
Answer:The variety of alleles/genes within a species or population.Question 34
Distinguish between species richness and species evenness. [2 marks]
Answer:Richness is the number of different species in an area (1); evenness is how equal the numbers of individuals of each species are (1).Question 35
Distinguish between primary and secondary succession. [2 marks]
Answer:Primary succession begins on newly formed or bare surfaces with no soil, such as bare rock or volcanic ash (1); secondary succession begins where soil and seeds already exist, such as after fire or abandoned farmland (1).Question 36
Define the term ‘pioneer species’. [1 mark]
Answer:The first species to colonise a bare area, usually hardy, fast-growing species that tolerate harsh conditions, eg lichens and mosses.Question 37
Describe the features of a climax community. [2 marks]
Answer:Stable, self-sustaining community in balance with the climate (1); high biodiversity, large complex species and stable food webs, with little further change in species composition (1).Question 38
Explain why small populations are vulnerable to extinction. [3 marks]
Answer:Low genetic diversity reduces ability to adapt to change (1); inbreeding increases harmful recessive alleles being expressed (1); genetic drift/chance events such as disease or a bad year can wipe out the population (1).Question 39
Distinguish between in-situ and ex-situ conservation. [2 marks]
Answer:In-situ conserves species in their natural habitat, eg nature reserves (1); ex-situ conserves species outside their natural habitat, eg zoos, seed banks, botanic gardens (1).Question 40
Describe the role of seed banks in conservation. [2 marks]
Answer:Store seeds of many species, including crop wild relatives, at low temperature and humidity (1); act as a genetic insurance that allows species to be regrown or reintroduced if they are lost in the wild (1).Question 41
State what the IUCN Red List shows. [1 mark]
Answer:The global conservation status (extinction risk) of species, from Least Concern to Extinct.Question 42
Explain why tropical rainforests have high biodiversity. [3 marks]
Answer:High, constant light, warmth and rainfall give high productivity all year (1); stable conditions over long periods allow species to evolve (1); complex layered structure provides many niches (1).Question 43
Give an example of a keystone species and describe its role. [2 marks]
Answer:Eg sea otter (1) controls sea urchin numbers, protecting kelp forests that shelter other species (1). Accept beaver, African elephant or wolf with an appropriate role.Question 44
Explain how a non-native invasive species can reduce biodiversity. [3 marks]
Answer:Has no natural predators or diseases in the new area so its population grows rapidly (1); out-competes native species for food, light or space (1); may prey on or spread disease to native species, eg grey squirrel and red squirrel (1).Question 45
Describe the features of a K-selected species. [2 marks]
Answer:Large body size, long life span, slow growth and late maturity (1); few offspring with a high level of parental care; population stable near carrying capacity (1).Question 46
State what the Ramsar Convention protects. [1 mark]
Answer:Internationally important wetlands, which are designated and managed for conservation and wise use.Question 47
Explain how the ozone layer allowed life to colonise land. [3 marks]
Answer:Oxygen from photosynthesis accumulated in the atmosphere (1); some oxygen formed ozone in the stratosphere (1); ozone absorbs harmful UV radiation, protecting organisms and DNA on land (1).Question 48
State two properties of water that support life. [2 marks]
Answer:Any two: excellent solvent for transporting substances; high specific heat capacity so temperatures are stable; liquid over a wide temperature range; transparent so light reaches photosynthetic organisms; ice floats so water below stays liquid.Question 49
Explain why the cause of decline must be addressed before a species is reintroduced. [2 marks]
Answer:If the cause (eg habitat loss, hunting, pollution) remains, released animals will decline again (1); the reintroduction would waste time and money and could harm the released individuals (1).Question 50
Explain why edge habitats and corridors matter when designing nature reserves. [2 marks]
Answer:Larger, less fragmented reserves have less edge effect and support bigger populations (1); corridors link reserves so animals can move, breed and exchange genes (1).