human impact

Question 1

describe three strategies apart from aquaculture which can be used to prevent overfishing and explain how each would help conserve stocks (3)

Answer 1

• restricted/minimum net mesh size so don’t catch young/smaller fish
• exclusion zones/seasonal restrictions so don’t catch breeding fish/juveniles/ so stock can recover
• quotas/ smaller fleets so less fish caught

Question 2

one method of decreasing damnds on wild fish stocks is the use of aquaculture the scottish salmon industry is one exaple one problem with raising salmon this way is the high build up of parasites such as lice which feed on blood and tissue of salmon why are these farmed fish more susceptible to infection by lice than wild fish and why is elimintating the lice a problem for fish farms (2)

Answer 2

• closely packed so lice/parasites/infection can easily spread from fish to fish
• cannot be easily killed as resistant to pesticides

Question 3

one method of decreasing damnds on wild fish stocks is the use of aquaculture the scottish salmon industry is one exaple one problem with raising salmon this way is the high build up of parasites such as lice which feed on blood and tissue of salmon
there are more environmental concerns that farmed fish can escape from there pens explain three reaons and why it is important to the environmnet that the escape of farmed fish is prevented (3)

Answer 3

• foreign species into new areas/invasive species/displace indigenous species/decrease biodiversity/reduce wild fish numbers/diversity of species
• compete for food/mates/habitat/affect food chains
• spread disease/infection/parasites to wild/native fish
• breed with wild fish and reduce genetic diversity/dilute gene pool/threaten long term survival of wild species/cause wild species to go extinct

Question 4

explain what is meant by an endangered species (1)

Answer 4

species that is seriously at risk of extinction

Question 5

give two advantages of using reintroduction of beavers from northern europe as a strategy for conservation in the UK (2)

Answer 5

• restores/increases/improves biodiversity/increases freshwater habitats by pond formation/increases shrub growth/insect life
• reducs flooding/reduces damage to habits/ slows water flow/filters sediment from water
• use of european beavers: maintains correct geentics of population/well adapted to environment

Question 6

there has been some re introduction of beavers into the Uk both legal and illegal. Give two reasons why people might be concerned about illegal, unregulated reintroduction of beavers (2)

Answer 6

• introduction of disease
• destruction/loss of land/habitat due to flooding/bogs/reduced flow of rivers below the dams/deforestation
• the wrong species would not be so well adapted/inappropriate habitat to beavers

Question 7

environmental conservation decisions can only be made on the basis of sound scientific principles. Give two factors that scientists would have to consider when planning the successful reintroduction of beaves

Answer 7

• habitat: revieving habitats is suitable
• research the resources and expertise are available for the establishment/protection
• consultation : with neighbouring landownder and local stakeholdep0rrs indicated majority of those consulted do not oppose reintroduction
• correct beavers : suitable disease free donor population of eurasian beavers is identified/ correct species is reintroduced

Question 8

explain wht the term planteary boundary means (2)

Answer 8

• safe operating level for humanity/a threshold value for a global proces that is affected by human activity/limits that global processes or systems must stay within
• above this value the global process will not be stable / below this value the global process will be stable/ exceeding boundary lead to gross global environmental change/irreversible damage if exceeded

Question 9

explain how deforestation can directly affect the planetary boundary for climate change (3)

Answer 9

• deforestation reduced carbon dioxide uptake
• burning of felled trees/transport of felled trees/use of fules in process trees puts carbon dioxide into the atomsphere
• decay of waste tree material

Question 10

using your knowldge of natural selection explain why more species become extinct recently compared to pre industrial times (3)

Answer 10

• in a changing environment some species’ adapatation became unsutable/they were selected against
• cannot adapat/evolve in a relativley short period of time/ animals cannot move fast enough/seeda cannot disperse quickly enough to another habitat where they were suitable adapted
• increased human population/industry.pollution is causing environmental change

Question 11

suggest how biodiversity loss may be delayed using conservation methods (4)

Answer 11

• seed/sperm/gene banks / rare breed soceities
• breeding programmes
• fishing quota/mesh size/exclusin zone/seasons
• trade restrictions/legistlation/CITES
• management of wild populations / practices
• restrict habitat destruction/ pollution/deforestation.other means of habitat destruction
• SSSIs / national parks/conservation areas/education/ecotrousism /NGOs

Question 12

in areas where red kites were absent and then re introduced the numbers increased much ore rapidly than in areas where they were already established explain the reasons for this (3)

Answer 12

• fewer predators
• less intraspecifci competition
• for food/nest sites/habitat
• less likely to pass on disease as fewer numbers initially

Question 13

explain why the location of nest sitess needed to be kept ecret with round the clock protection (1)

Answer 13

theft of eggs/chicks/poachers/hunting

Question 14

many red kites chicks are tagged so that their survival and lifespan can be monitored. survival rates in northern scotland are poorer than elsewhere mainly because of illegal poisoning and shooting on grouse shooting estates
suggest two ways in which society could improve the survival rates of red kites (2)

Answer 14

• prosectution /legislation/ban hunting
• education/increase awareness/ecotourism
• making holding of poisons illegal/difficult to obtain
• feeding sites
• breeding programmes

Question 15

state what is meant by SSSs and why red kites may breed more successfully in these sites (2)

Answer 15

• site of special scientific interest
• SSSIs protected from development or other damage

Question 16

with reference to information provided about lost nirtogen and phosphorus and your own knowledge explain the possible ecological impacts of fish farming in the areas where it takes place and describe other ways to overcome the problem of overfishing. explain how these methods are used to prevent overfishing (9)

Answer 16

eutrophication
* the nitrogen in the food fed to the fish may be lost as uneaten food, in faeces and ammonia
* the extra N and P in the water can be used by algae to grow this algal bloom at the water surface can block light to the aquatic plants in the deeper water
* with no light these plants cannot photosynthesise and so die
* decomposers with decay the dead organic matter they use aerobic respiration and so use up oxygen from the water
* the water becomes deoxygenated and fish and other oxygen requiring species die
* anerobic bacteria may start to reduce nitrates - denitrification
other imapcts of fish farming
* the farmed fish tend to be packed tightly into a small area
* lead to diseases passing through a population quickly and these can spread to local wild fish population
* to keep stock healthy antibiotics are used lead to antibiotic resistant bacteria developing
* pesticides used to kill the parasites may also be toxic to some of the local marine invertebrates
* farmed fish may have a selective advantage over wild species
methods of preventig overfishing
* net mesh sizes can be decrease large mesh sizes allow immature fish to escape and they can go on to intebreed
* closed season for fishing thee will be at times when fish are breeding so stocks are replenished
* quotas - aggreements which limit catches brought ashore
* around the coast there are exclusion xones where fishing is not allowed these areas allow fish to reproduce without being caught
* landing size refulations have been introduced which only alloing fish of a certuan size to be caught allow fish to return for breeding fish of non traditional varities has allowed stocks of other fish to recover