human influences on ecosystems (topic 20) Flashcards

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1
Q

what are some methods that humans use to increase food production

A

agricultural machinery, chemical fertilisers, insecticides, herbicides, selective breeding

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2
Q

why is agricultural machinery used

A

reduces labor cost, time needed to farm, reduces food price, farmers can use more land to produce a greater quantity of food more efficiently,

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3
Q

why is chemical fertilisers used

A

fertiliser is a substance that contains important nutrient for plant growth eg. magnesium and nitrates
they increase yield of crops
natural fertilisers improve soil structure, artificial does not

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4
Q

why are insecticides used

A

Substances used to kill or control the number of unwanted insects. improved quality and yield

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5
Q

why are herbicides used

A

Substances intended to kill weeds and other plant pests. reduce competition with weeds

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6
Q

why is selective breeding used

A

improve production by
crop plants and livestock

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7
Q

what are examples of intensive farming methods

A

monoculture, intensive livestock production

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8
Q

monoculture

A

Growing a single crop across a large area.

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9
Q

advantages of intensive farming are

A

more simple- only one crop considered when preparing soil choosing fertiliser specific herbicides and insecticides can be used

improves efficiency and improves yield- crop or animal grows potimally produced in efficient way, large areas can be used

reduces production cost- farmer works in focused and efficient method costs lower, increases profit for farmer

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10
Q

disadvantages of intensive farming

A

land clearance- deforistation to crop plant, leads to lack of biodiversity

reduced biodiversity- pathogens and insect pasts grow more rapidly more insecticides used which may kill insects which arent pests, reducing food available for other animals

soil damage- heavy machinery used, compacts soil, reducing the amount of water and air it can hold, more difficult for plants to grow, can cause erosion, soil wahsed away by rain, wind or flooding, farmer only plants same plant nutrients used up, more fertilisers used, which can cause erosion

water pollution- water runoff from fields can carry fertilisers and herbicides, isnecticides, harm organisms in water, can cause eutrophication in rivers and lakes

air pollution- animal waste, methane, greenhouse gases,

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11
Q

biodiversity

A

the number of different
species that live in an area

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12
Q

what are the reasons for habitat destrcution

A

increased area for housing, crop plant
production and livestock production
extraction of natural resources (pollution is created by fuels when they are burned
the search for oil or gas damages natural habitats,drilling and mining operations need wells, roads, pipelines and other facilities.)
freshwater and marine pollution

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13
Q

how can humans have a negative impact on
habitats

A

altering food webs and chains

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14
Q

what can deforistation lead to

A

reduced biodiversity
flooding
loss of soil
extinction of species
an increase in carbon dioxide in the atmosphere.

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15
Q

how does deforestation lead to reduced biodiversity

A

As trees in a forest are the primary producers, they are the producers of many food webs. Trees also provide valuable habitats and food for many organisms in the forest. Certain creeping plants depend on the trees for access to sunlight (Figure 1). Without the trees, many food webs would collapse.

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16
Q

how does deforistation lead to flooding

A

trees removed water cycle affected, trees and other vegetation hold soil together, hold water in the ground, no vegetation rain flows directly into rivers and lakes wahses away more of the soil causing floodngs

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17
Q

how does deforistation lead to loss of soil

A

trees and vegetation help keep soil in place, reduce erosion, land cleared protective layer of vegetation lost, soil may then be blown away or washed away

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18
Q

how does deforistation lead to increased co2

A

during photosynthesis co2 is used as reactant, when trees or plants are cut down, this doesnt happen increasing presence of co2 in the atmosphere, also if vegetation cut down is burned this process releases co2

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19
Q

pollution

A

Release of any substance that has an undesired, unexpected, harmful or toxic effect on the environment.

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20
Q

what are some sources of water pollutants and their effects

A

untreated sewage- may carry harmful pathogens that cause disease; uses up oxygen when it rots; hormones affect reproduction of some organisms

fertiliser runoffs- causes algal blooms and eutrophication

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21
Q

what is the probelm with untreated sewage

A

causes diseases, skin irritation, as untreated sewage decays, decomposers respire using up oxygen in water, killing aquatic life, may alos cause eutrophication because of releasion of nitrates and phosphates

22
Q

what is the problem with fertilisers

A

contain mineral ions, help algal blooms to grow rapidly, cover surface of water, stop sunlight from entering, reduce levels of oxygen, aquatic life dies
also stop other producers from photosynthesising, dia and are decomposed by decomposers, carry out aerobic respiration, use up oxygen, killing aquatic life

23
Q

problem with plastic in aquatic life

A

takes long time to decompose, contribute to low levels of oxygen
non-biodigradbale plasticsstay in enviornment, marine life can ingest blocking digestive system animal starves, or gets tangled in plastic

24
Q

problem with plastic in terrestial life

A

break down into smaller pieces, exposed to air water and light, form toxic compounds
when plastic breaks down release greenhouse gases
toxins from plastics, can leach soil
animals can also mistakingly eat
burning plastic releases toxins

25
Q

greenhouses gases

A

Any atmospheric gas, such as carbon dioxide or methane, that can absorb thermal energy and so contribute to the greenhouse effect.

26
Q

what can contribute to carbon dioxide releasion

A

burning fossil fuels, producing electricity and deforestation

27
Q

global warming- climate change

A

However, the additional carbon dioxide and methane is causing an enhanced greenhouse effect. More heat energy is prevented from escaping into space, leading to increases in the average global temperature

28
Q

sustainable resoucre

A

one which is produced as rapidly as it is removed from the environment so that it does not run out

29
Q

non-renewable resource

A

Something that is being used up faster than it is being formed. eg. fossil fuels

30
Q

what are some areas in the forests important to conserve

A

the edges of rivers, to promote the retention of water
mountain slopes, to reduce erosion
areas with rare species and habitats

31
Q

what are some ways to conserve forests

A

reforestation, setting quotas for logging, which may mean banning logging entirely in some areas
using education programmes to help local people to understand why the forest is important
creating protected areas.

32
Q

how do quotas help conserve forests

A

A quota is a limited amount of a resource that may be removed from a given area or within a set time period

33
Q

how do protected areas help conserve forests

A

an area of land that is set aside for conservation purposes only. This allows the ecosystems to thrive in that area.

34
Q

how can fish stocks be conserved

A

education, closed seasons, protected areas,
controlled net types and mesh size, quotas and monitoring

35
Q

how do closed seasons help conserve fish stocks

A

breeding season of a fish can be closed to fishing. This allows the fish to reproduce optimally.

36
Q

how do protected areas help conserve fish stocks

A

aims to provide safe havens for fish populations to recover from prior overfishing. Protected areas also protect aquatic biodiversity, which is essential to all ecosystems.

37
Q

how do quotas help conserve fish stocks

A

Banning the catching of fish below a certain size maintains the number of young fish so that they can grow and reproduce

38
Q

how do controlled mesh size help conserve fish stocks

A

Using a bigger size mesh allows immature fish and non-target fish to escape. This protects the breeding cycle of the fish and reduces unintentional catching of other species. The type of net used can also determine which species of fish are more likely to be caught

39
Q

how do monitoring help conserve fish stocks

A

includes the age at which it reproduces, where it reproduces and the size of its population. Monitoring population size and breeding patterns can also help authorities to decide which actions need to be taken for conservation.

40
Q

state reasons why a species may become endarged

A

destruction of habitat
pollution
climate change
hunting
introduced species
overharvesting.

41
Q

correlation between population size and variation

A

As the size of a population decreases, genetic variation within the population is also reduced
fewer different alleles expressing different phenotypes, so the population is less able to adapt to changes in the environment. more vulnerable to diseases.

42
Q

how can Endangered species be conserved

A

monitoring and protecting species and habitats
education
seed banks
captive breeding programmes.

43
Q

explain monitoring and protecting species

A

monitor migration routes
note changes in behaviour
observe feeding and mating activities
record changes to habitats.

44
Q

explain education

A

education helps to increase local people’s awareness and understanding of the species and the role it plays in the habitat.

45
Q

explain seedbanks

A

Seed banks store samples of seeds from many plant species
provides resources and breeds that can be used to develop new varieties of plants
seeds are kept at a low temperature and humidity to help preserve them

46
Q

explain captive breeding

A

Conservation of endangered species by planned breeding of animals that are held in zoos and wildlife parks.
helps to increase the number of individuals in a population

47
Q

Describe the reasons for conservation
programmes

A

maintaining or increasing biodiversity
reducing extinction
protecting vulnerable ecosystems
maintaining ecosystem functions, limited
to nutrient cycling and resource provision,
including food, drugs, fuel and genes

48
Q

explain reproduction in captivity

A

Breeding animals in captivity requires a lot of management and careful monitoring
If the wild population is small, then breeding programmes need to be careful not to breed closely related members. It is important to maintain genetic variation
not always feasible or desirable to physically move an animal from one location to another

49
Q

explain artificial insemmination

A

obtain a sperm sample from the desired male
semen is then harvested from the sample and transported to the breeding female
semen is artificially inserted into the female’s reproductive tract

50
Q

explain in vitro fertilisation

A

sperm from the male and eggs from the female are both extracted
Fertilisation is carried out under controlled conditions in a Petri dish in the laboratory
Once the egg is fertilised and has started to divide into an embryo, it is inserted into the reproductive tract of a female.