human influences on ecosystem Flashcards

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1
Q

describe how humans have increased food production

A

Agricultural machinery to use larger areas of land & improve efficiency
* farmer can cultivate greater area of land in shorter time then using manual labor and animals.

Chemical fertilizers to improve yields
* add more mineral ions such as nitrate ions to soils nto containing sufficient amounts.

Insecticides to improve quality & yield
* sprayed onto crops to kill insect pests that might reduce yields/make it less appealing.

Herbicides to reduce competition with weeds
* to kill weeds, which would compete w crop plants; reduces their growth.

Selective breeding to improve production by crop plants & livestock
* includes cattles (Cows), fish, poultry, that are larger and produce more meat and crop plants that grow faster and are disease-resistant.

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2
Q

Describe the advantages and disadvantages of large-scale monocultures of crop plants

A

Advantages
* Efficient; all plants are planted, taken care of, harvested in the SAME way, using SAME chemicals & machinery; makes it easier to manage crops. Cost effective.

  • Higher yields from same area of land; more food & profit for farmers.
  • Food produced is cheaper for consumers.

Disadvantages

  • Reduction in biodiversity ; fewer plant species the natural ecosystem. fewer plant species = no habitats provided for as many organisms.
  • increase in pesticide use ; excess pesticides washed into water; pollutes freshwater environment.
    kills useful insets, and food chain disruption.
  • Low genetic variation ; pest/disease affecting plant species = can kill ALL crops being grown.
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3
Q

Describe the advantages and disadvantages of
intensive livestock production

A

Advantages

  • Keeping animals in confined place = easier to monitor & protect from predators.
  • Animals use less energy for movement & controlling body temp; more energy available for growth; more meat being produced.
  • Greater profit for farmer, cheaper for consumers.

Disadvantages
* Waste from livestock - builds up - diseases easily spread - waste can run into water sources - pollution

  • Diseases spread dealt using regular doses of antibiotic - risk of antibiotic resistance
  • Welfare issues for livestock; may suffer in crowded conditions
  • Unethical
  • Large quantities of water may need to be provided; surrounding environment affected.
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4
Q

what is monoculture

A

area of ground covered by a single crop with almost no other species present.

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5
Q

what is intensive livestock production?

A

when livestock are farmed intensively; large no of animals kept in a small area. it limits movement of animals.
keeps them in temp controlled environment

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6
Q

define biodiversity

A
  • number of diff species that live in an area
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7
Q

describe the reasons for habitat destruction

A
  • to make land available for growing crops, farming livestock, building houses, factories, roads
  • mining for natural resources (metal ores) building materials, fossil fuels.
  • cities and factories create wawste thats often dumped in rivers and ends up in seas; causes freshwater and marine pollution that can harm aquatic environments.
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8
Q

how can humans have a negative impact on habitats?

A
  • altering food webs and food chains
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9
Q

negative effects of deforestation

A

Loss of biodiversity
* when habitats are destroyed, species living in them will die or move away, reducing biodiversity in that area.

Extinction
* species can die out if they can’t find or unable to move to suitable habitats.

Loss of soil
* when trees are removed, there’s no roots to stabilize the soil during heavy rain. Soil is washed away, and nutrients are lost.
* harder for new trees to grow later.

flooding
* trees slow down rain as it falls; without trees, flooding is more likely. destroys habitats and wildlife.

increase of co2 in atmosphere
* increased co2 leads to global warming

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10
Q

Describe the effects of untreated sewage and excess fertiliser on aquatic ecosystems

A

Untreated sewage
* eutrophication
* microorganisms (decomposers) break down sewage
* microorganisms population increases
* increased respiration of microorganisms decreases oxygen content of water

excess fertilizer
* eutrophication
* extra nutrients (ions and nitrates) enters water.
* cause algae to grow faster and block out light.
* plants cant photosynthesise due to lack of light and start to die
* microorganisms (deocmposers) feed on dead plants increase in number. they respire aerobically, so the amount of dissolved oxygen in water is reduced, as decomposition increases.
* organisms that need oxgen dissolved in water (Fish) die.

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11
Q

Describe the effects of non-biodegradable plastics, in both aquatic and terrestrial ecosystems

A

Aquatic ecosystems
* eating plastic items; intestinal blockages in organisms
* poisoning from chemicals.
* large quantities of buildup in ocean
* loss of biodiversity
* disrupts food chain

Terrestial ecosystems
* plastics can give out poisonous toxins and chemicals that causes land pollution; can kill
* toxic gasses released into atmosphere when plastic disposed by burning; CO2 produced.
* landfills take up valuable space.

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12
Q

Describe the sources and effects of pollution of the air by methane and carbon dioxide

A

Sources of pollution by CO2
* fossil fuels (coal, oil, natural gas)
* when fossil fuels are burnt, they release co2.
* fossil fuels burnt in power stations, transport
* deforestation also increases amount of co2

Sources of pollution by methane
* methane gas naturall produced: rotting plants
* man-made: growing rice and raising cattle

enhanced greenhouse effect
* increasing lvl of CO2 and methane are causing an increased green house effect; causing earth to heat up; this is global warming.

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13
Q

whata sustainable resource

A
  • one which is produced as rapidly as it is removed from the environment
  • so that it doesn’t run out
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14
Q

Explain how forests can be conserved

A

Education
* ppl understand value of biodiversity in forests; they’ll want to protect them from deforestation

protected areas
* deforestation banned in areas by law

quotas
* limits applied to no. of trees that can be cut down in forests

replanting
* replace trees that are removed (reforestation)
* no. of trees can be maintained

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15
Q

Explain how fish stocks can be conserved

A

Education
* knowing abt improtance of conserving fish stocks means that ppl shopping for them can make better choices.

closed seasons
* some areas of the sea can be closed for certain times of the year such as breeding szn. allows fish stocks to replenish

protected areas
* areas of sea can be completely closed to fishing
* fishes can live and breed safely.

controlled net type and mesh size
* using bigger mesh size allows unwanted species to escape
* younger fish able to slip through net, allowing them to reach breeding age

quotas
* limit on number & size of fish that can be caught
* helps prevent certain species from being overfished

monitoring
* inspectors enforce rules, check catches brought to land

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16
Q

Explain why organisms become endangered
or extinct

A
  • climate change
  • habitat destruction
  • hunting
  • overharvesting
  • pollution
  • introduced species
17
Q

describe how endangered species can be conserved

A

Monitoring & protecting species & habitats
* monitoring species’ no. helps identify species most under threat.
* protected areas set up to protect organisms & habitats from hunting/deforestation.

Education
* teaching ppl about natural world helps them under abt conservation

Captive breeding programmees
* bred in captivity. set up to prevent extinction of endangered species.
* easier for animals to increase numbers in captivity. less infant mortality more offspring can reproduce.

Seed banks
* seeds of endangered plant species can be kept in a seed bank
* protects and saves plant genetic diversity.

18
Q

Describe the reasons for conservation
programmes

A

maintaining or increasing biodiversity
* conserving species means that ecosystem functions like nutrient cycling will be maintained
* helps increase/maintain biodiversity.

reducing extinction
* conserving one species may stop others from being extinct
* if 1 species extinct = affects food chain/web

protecting vulnerable ecosystems
* organisms can continue to live in their natural habitat

maintaining ecosystem functions
* resources can be used by humans e.g animals for food, plants for drugs, wood for fuel, and genes from organisms.
* conservation programmes ensure resource provision from environment can continue

18
Q

Describe the use of artificial insemination (AI) in captive breeding programmes

A
  • sperm collected from male inserted into female’s cervix to allow fertilization to take place.
  • helps individuals who are unable to breed together naturally.
  • helps increase genetic variation
19
Q

Describe the use of In Vitro Fertilization (IVF) in captive breeding programmes

A
  • egg is removed from female’s ovaries
  • fertilized using sperm in laboratory
  • embryo is planted into female
  • helps individuals breed together if aren’t able to naturally
  • collected eggs placed in sterile petri dish
  • necessary to wait ovulation day to take eggs.
20
Q

Explain the risks to a species if its population size decreases

A
  • Fewer individuals
  • Reduces genetic variation in population
  • Less genetic variation can lead to inbreeding
  • Less able to breed and produce healthy offspring
  • Less able to adapt to changing conditions