Human influences on ecosystems Flashcards iGCSE Biology

[a]

• Kills / damages plants;
  
• Acidification of lakes;
  
  
  • Fresh water fish / invertebrates die;
    
• Acidic soil leaching;
  
• Dissolves limestone / marble / sandstone aw;
• (acidic) soil leaching AW;
• Released (named) metals; e.g. Aluminium.
• Nutrients in soil no longer available to plants;
• Prevents decomposition;

[a] Effects of waterborne chemical wastes on the environment are:

• Destruction of aquatic habitat;
  
• Heavy metals are toxic;
  
  
  • Consequence of a named heavy metal (e.g: Minimata disease caused by mercury)
    
  • Bioaccumulation / biomagnification (of heavy metal);
    
• Acid burns skin and plants ;
  
  
  • Decreases pH;

[a]

1. Algal bloom blocks light from reaching water plants,
   
2. There is reduced photosynthesis, so (fixed) water plants die ;
   
3. Thus, less oxygen released by plants in the water
   
4. Dead plants are decomposed by bacteria ;
   
5. Bacteria multiply rapidly, so there is more aerobic respiration in the water;
   
6. Therefore, the low levels of oxygen causes the death of aquatic creatures;

[a]

• Carbon dioxide is a greenhouse gas;
  
• (enhanced) greenhouse effect (in context of carbon dioxide);
  
• Infra-red radiation from sun absorbed by carbon dioxide / greenhouse gases;
  
• Heat travels, back to the surface;
  
• Heat cannot leave from the atmosphere;

[a] 

• Global warming;
• Increase in rate of photosynthesis;
• Causes increase in plant growth / crop yield / vegetation;
• Any two qualified examples of environment effects of global warming e.g. flooding, extreme weather conditions, qualified habitat change, reduced
• Biodiversity;
• AVP; e.g. disruption to migration routes.

[a]

• High risk of extinction;
  
• Less chance of, reproduction / pollination AW;
  
• High risk of genetic diseases;
  
• Less / little / no, (genetic) variation;
  
• (Small population so) more vulnerable to, pests / disease / catastrophe;
  reduced number of alleles;
  
• Less likely to, adapt to / evolve to / cope with, (named) change in environment;

[a]

• Restrictions:
  
  
  • Restrictions on times when fishing can occur; not in breeding season;
    
  • Exclusion zones / nursery zones / ‘no take’ zones / reserves;
    
  • Total ban for some species;
    
  • Laws that restrict net size;
    
• Fish Stocks
  
  
  • Monitoring fish stocks;
    
  • Encourage captive breeding (of wild fish);
    
  • Re-stocking (of wild stocks);
    
  • Encourage farmed fish; e.g. Provide subsidies
    
  • Education / raise awareness / any example;

[a] We can reduce the effects of acid rain through:

• Add lime(stone) / calcium carbonate / CaCO3 / alkali, to, lakes / rivers / soils;
  
• Use less fossil fuels;
  
• Use low sulfur fuels;
  
• Desulfurisation of, coal / oil;
  
• Flue gas desulfurisation / ‘use (wet) scrubbers’ / neutralise waste gases with lime;
  
• Catalytic converters / use electric cars;
  
• Idea of international treaty for reducing emissions;

[a]

• Agricultural machinery
  
• Chemical fertilisers
  
• Insecticides
  
• Herbicides
  
• Selective breeding

[a] The Sources of Pollutant: 2,4-D are Weedkiller/Herbicide.

[a] The Effects of Pollutant: 2,4-D on Environment are:

[a] The Sources of Pollutant: DDT are Pesticide Sprays.

[a] The Effect of Pollutant: DDT on Environment is accumulation in tissues of animals.

[a] The Sources of Pollutant: Heavy Metals are: factories / industries / mining / exhaust from transport / chemical plants / sewage (sludge)

[a] The Effect of Pollutant: Heavy Metals on Environment are disrupt function of plants, causes brain damage.

[a] The Sources of Pollutant: Ionising radiation are nuclear fall-out / radioactive waste / nuclear industries / nuclear power plants / uranium / plutonium / X-rays;

[a] The Effect of Pollutant: Ionising radiation on Environment are Mutations / Cancers.

[a] The Sources of Pollutant: Phosphate are Fertilisers / Detergents / Sewage.

[a] The Effects of Pollutant: Phosphate on Environment are Eutrophication of streams, rivers, and lakes.

[a] The Sources of Pollutant: Sulfur Dioxide are (Combustion of) coal / oil / factories / power stations / chemical plants / exhaust from transport.

[a] The Effects of Pollutant: Sulfur Dioxide on Environment are Acid rain, damage to trees, e.g: death of leaves.

[a]

• Hunting / more predators
  
• Destruction of habitat
  
• Pollution
  
• Disease
  
• Loss of food
  
• Climate change
  
• Very small population

[a]

• Animals at higher trophic levels live longer;
  
• Eat many of the animals below them in the food chain;
  
• PCBs cannot be, excreted / eliminated / removed / broken down;
  
• So build up in the body (tissues);
  
• Bioaccumulation / biomagnification;

[a]

• Kills, water plants / algae;
  
• Lack of, producers / food for herbivores;
  
• Bioaccumulation / described;
  
• Reduced biodiversity;
  
• Lack of roots causes erosion / silting / flooding;

[a]

• Deforestation;
  
• Climate change / global warming;
  
• Change in land use / described;
  
• Desertification;
  
• Pollution;
  
• Plant hunters;
  
• Increase in (new / invasive), grazers / predators;
  
• Competition with, introduced species / alien species;
  
• (New) disease / pests;
  
• Lack of pollinators;

[a] Development providing for the needs of an increasing human population without harming the environment is called Sustainable development.

[a]

• Specialised and efficient harvesting technique for one species
  
• Specific mineral/water requirement needed
  
• High yield
  
• Highly selected strains/Better quality

[a]

• Loss of habitat / described;
  
• Addition of (named polluting) chemicals;
  
• Human animal conflict;
  
• (The crop is often an) introduced species;
  
• Loss of biodiversity or loss of, suitable / variety of, food sources;
  
• Outbreaks / spreading, of diseases / pests / plagues;

[a]

• When trees are cut down, the roots die, leaving the soil unanchored. Soil erosion occurs, causing silting of rivers, increasing the risk of flooding. Since there are also no trees to absorb the water, rate of evaporation increases, causing desertification.
  
• Habitats are lost, resulting in lost of biodiversity and also causing a disruption to the food chain.
  
• Planted forest is a monoculture;
  
• Susceptible to pest / disease;
  
• Loss of biodiversity;
  
• Roots die so do not bind the soil.
  
• Soil erosion;
  
• Silting of rivers;
  
• Reduced (soil) fertility;
  
• No trees to absorb the water;
  
• Increased risk of flooding;
  
• Increased rate of evaporation / land is exposed to drying;
  
• Desertification / decreased soil water ;
  
• Loss of, habitat / places where organisms live / described;
  
• Disruption to food chain / described;
  
• Endangered / extinction, of species or loss of biodiversity;
  
• AVP; named example of affected ‘land’ organism in context / removed
  
• Trees cause nutrient cycling disruption / lack of decomposition

[a]

• Effect of waste (faeces and urine) on, waterways / crops;
  
• Disease spreading to, wild populations / humans;
  
• Use of antibiotics and (spread of) antibiotic resistance;
  
• Use of pesticides;
  
• Loss of biodiversity;
  
• Release of, (named) greenhouse gases / carbon emissions;
  
• Named consequence; e.g. climate change / global warming
  
• Providing food for livestock requires monocultures;
  
• Deforestation / habitat loss;
  
• Idea that livestock production is an inefficient use of, crop plants / energy;
  
• AVP; e.g. use of hormones and effect on wild populations / feminisation of fish

[a]

• Encourages biodiversity;
  
• Prevents extinction;
  
• Encourages genetic diversity (within each species);
  
• Maintain food, webs/chains
  
• Food for predators
  
• Maintain, gene, pool / diversity
  
• Availible for scientific research / source of medicine
  
• Preserve for future generations / ethical reasons