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Biology🧬 > Human Impact🤦🏻‍♂️ > Flashcards

Human Impact🤦🏻‍♂️ Flashcards

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1
Q

Why are species becoming endangered?

A

•Loss of habitat
-habitat can become too small or too widely dispersed to support a species
•Invasive species
-some species exploit their new ecosystem
->outcompete native species
->predation of natives
•Overexploitation
-exploiting resources
-overfishing
-poaching
•Pathogens/disease
-spread of domesticated animals
-native population may have little resistance
•Pollution
-pesticides/fertilisers/greenhouse gases/thermal/light/noise
-reduce survival rates of local animal populations

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2
Q

What are upwelling zones?

A

•A combo of winds and currents causes water close to the sea bed to rise
-upwelling carries nutrients into higher water where there is sufficient light to support photosynthesis

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3
Q

Where are fish populations most abundant?

A

•Where phytoplankton productivity is highest
•Phytoplankton productivity is directly related to mineral nutrients in the surface waters
-Generally, oceans have a low conc of nutrients at surface so low pop of phytoplankton and fish

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4
Q

What are demersal fish?

A

Bottom-feeding fish

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5
Q

What are pelagic fish?

A

Surface-feeding fish

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6
Q

Stock size equation

A

Sn (stock size now)
= Sn (stock size last year)
- 1
+ G (biomass added by growth of fish already in stock)
+ R (biomass added by recruitment)
- M (biomass lost by mortality/harvesting)

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7
Q

Impact of overfishing

A

•Causes fall in number
•Young, smaller fish become increasingly common
•Catching large numbers of small fish before they spawn can reduce the ability of the population to reproduce
-may lead to fall in local populations

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8
Q

What are sustainable yields (in fishing)?

A
  • Fish must not be caught faster that the fish stocks can replenish themselves
  • Varies with size of population and its growth rate
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9
Q

What is maxim sustainable yield (MSY)?

A

The largest amount of a naturally renewable resource that can be regularly harvested without causing a decline in stock

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10
Q

What regulations can prevent overfishing?

A

•Quotas
-less endangered fish are removed from the ocean-> allows recovery
•Minimum mesh sizes
-should be large enough to allow immature fish to pass through-> can survive to breed
•Closed seasons
-times when fishing is not allowed
•Exclusion zones
-areas where fishing is banned completely

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11
Q

Benefits of fish farming

A

•Can reduce pressure on wild stocks of fish, while still meeting human demands

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12
Q

Negatives of fish farming?

A

•Can encourage spread of pathogens/parasites (due to high density) which could spread to wild fish
-antibiotics & pesticides are used->can harm marine invertebrates
•Waste produced by fish can cause increased nitrate concentration
-leads to eutrophication
•Less genetic variation due to selective breeding
•Less biodiversity due to escaped farm fish
-reduces gene pool
-invasive species & hybrid sterile fish out-compete wild fish

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13
Q

Causes of deforestation

A
  • Firewood
  • Make room for infrastructure
  • Pulp and paper
  • Timber for construction
  • Acid rain
  • Replacement of native trees with fast-growing species
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14
Q

What is the effect of deforestation on biodiversity?

A

Reduce biodiversity of species

-some can have potential medical benefits

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15
Q

What are the effects of deforestation on nutrient cycles?

A
  • Forest burning releases huge quantities of CO2 directly and quickly into the atmosphere
  • Burning trees significantly reduces nitrogen held in ecosystem
  • Tree roots hold soil particles together
  • Tree canopy reduces rain eroding soil
  • Nutrients are lost through leaching
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16
Q

Examples of sustainable development

A
  • Managed timber production
  • Land designated as set asides
  • Agroforestry
  • Ecotourism
  • Coppicing
  • Selective cutting
  • Plantations
  • Education
  • Local incomes
17
Q

What are the aims of biological conservation?

A
  • Maintain quality of natural environments and their biological resources
  • Actively managing biotic and abiotic components to ensure the survival of the maximum number of species and genetic diversity
  • Maintain biodiversity, ensure survival of endangered species and conserve existing gene pools
18
Q

What is sustainable development?

A
  • Development that can continue indefinitely
  • Based on exploiting renewable resources, while minimising environmental damage, maintaining the overall integrity of the ecosystem and conserving species
19
Q

What is in situ conversation?

A

•Conservation of species in their natural habitats, e.g.

  • mowing
  • grazing
  • burning
  • coppicing
  • control of water level
  • wildlife corridors
  • selective cutting
  • sustainable replanting
  • pollarding
20
Q

How can burning conserve species?

A

It can halt succession to keep particular communities in an environment

21
Q

What is coppicing/pollarding?

A
  • Coppicing - pruning shrubs to ground level
  • Pollarding - similar but higher up
  • Allows regeneration
22
Q

What is ex situ conservation?

A

•Preservation of components of biodiversity outside their natural habitats, e.g.

  • breeding programmes
  • sperm/seed banks
  • reintroduction
  • restricting trade of endangered species
  • controlling pollution
  • international cooperation and treaties
23
Q

Why is conservation of genetic diversity important?

A
  • Conservation of species ensures the conservation of existing gene pools
  • Ethical reasons
  • Prevent loss of potentially useful genes to man and the species
24
Q

What happens if breeding numbers become too small?

A

•Less chance of finding a mate
•Less genetic diversity/smaller gene pool
-inbreeding
-alleles are less likely to help species survive environmental changes

25
Q

What is the concept of planetary boundaries?

A

•Since industrial revolution, activity of humans has become the main cause of global environmental change
•If crossed, may result in abrupt/irreversible environmental changes
-remaining in these boundaries will allow human societies to continue to develop sustainability

26
Q

What are the 9 planetary boundaries?

A
  • Climate change
  • Biosphere integrity (biodiversity)
  • Biogeochemical (impact on nitrogen and phosphorus cycle)
  • Ocean acidification
  • Land use change
  • Global fresh water consumption
  • Atmospheric ozone depletion
  • Atmospheric aerosol loafing
  • Novel entities (chemical pollution)
27
Q

Which boundaries have been crossed?

A

•Climate change
-CO2 levels have not reduced
•Biosphere integrity
-extinction rate equals that of the last 5 mass extinction periods
•Biogeochemical
-eutrophication has impacted marine and lake ecosystems

28
Q

Which boundary has been avoided?

A

Ozone depletion

  • protocols
  • ban on CFCs and other chemicals
29
Q

Which boundaries are at risk of being crossed?

A
  • Ocean acidification
  • Global freshwater consumption
  • Land use changes
30
Q

How could crossing other boundaries be avoided?

A
  • Reduction in deforestation
  • Changes to farming practices
  • Reduction In burning of fossil fuels
31
Q

Which boundaries have insufficient data?

A 
•Novel entities
•Atmospheric aerosols 
-large variety of chemicals & particles in the environment 
-boundaries are unquantified
-further research needed
32
Q

What is monoculture?

A

•Single crop grown over large land space
•Same nutrients removed annually, so needs fertilisation
-eutrophication
•Increased pest populations
-increased pesticide usage which decreases biodiversity

33
Q

Why may a species become endangered when its population falls to a very low number?

A

•Less likely to cross paths and mate - sexually reproduce
•Population growth will fall
•Smaller gene pools
-no alleles to resist environmental changes

34
Q

Why do seeds at a seed-bank need to be dried and stored in cold conditions?

A
  • Dried to prevent harmful ice crystals forming in the seed

* Cold conditions prevent germination of seed - stops enzymes actions

35
Q

Effect of mechanisation

A

•Larger fields created to allow larger vehicles
•Removal of hedgerows
-reduction in biodiversity

36
Q

What is meant by an endangered species?

A

Risk of extinction

37
Q

What are some factors that scientists would have to consider when planning the successful reintroduction of a species?

A
  • Research
  • Consultation
  • Correct species
  • Habitat
38
Q

Explain how deforestation can directly affect the planetary boundary for climate change

A
  • Reduces CO2 uptake
  • Burning/transport of felled trees/use of fuels for processing trees puts CO2 into the atmosphere
  • Decay of waste tree material
39
Q

Why have more species become extinct recently compared to pre-industrial times?

A
  • In a changing environment, some species’ adaptations become unsuitable
  • They can’t adapt/evolve in a relatively short period of time/animals can’t move fast enough/seeds can’t disperse fast enough
  • Increased human population/industry/pollution is causing environmental change

Biology🧬 (24 decks)

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