4.7 Ecology Flashcards
What is biodiversity and why is it important?
the variety of all the different species of organisms on earth/within an ecosystem. It is important because it makes sure that species in an ecosystem are stable
How does biodiversity make sure an ecosystem is stable?
one species isn’t dependent on another for food, shelter, maintenance of the physical environment
How is biodiversity reduced?
human activities such as waste production, deforestation and global warming
Why have humans’ consumption of resources and waste production increased? How does pollution occur?
the rapid growth in human population and increased living standards -> humans are using more resources -> more waste is produced -> more pollution
How does pollution in water occur?
sometimes untreated sewage is accidentally released into streams and rivers, fertilisers from farms. Both cause dissolved oxygen levels to fall, killing aquatic organisms. Finally, sometimes toxic chemicals from factories are released into the river
How does pollution in air occur?
air pollution, such as burning coal in power station to release acidic gases and smoke/smog
How does pollution on land occur?
waste in landfills, landfills destroy the habitats of plants and animals. Toxic chemicals can also leach out of landfills and pollute soil or dumped onto the land
How does pollution affect biodiversity?
pollution kills animals and plants, reducing biodiversity
Human activities that reduce the amount of land?
building, quarrying, farming and dumping waste (landfills)
Why are peat bogs/lands destroyed?
to produce cheap compost for gardens and farms to increase food production and is burned to release energy -> reducing the area of this habitat
How does the destruction of peat bogs contribute to the greenhouse effect?
contains large amounts of dead plant materials (trapped carbon)
Decay is slow as there is not enough oxygen, the decay or burning of peat releases carbon dioxide into the atmosphere -> contributes to climate change
Why does large-scale deforestation occur (in tropical areas)?
- to provide land for cattle and rice
fields, and to grow crops for biofuels - Biofuels are plant based fuels to burn instead of fossil fuels
How does deforestation contribute to climate change?
- Increases carbon dioxide because reducing trees means reducing photosynthesis, meaning more carbon dioxide is left in the atmosphere
- Burning trees produces carbon dioxide, releasing smoke that can harm animals
How does deforestation affect biodiversity?
a habitat (presumably with high biodiversity), has now been destroyed -> reducing biodiversity
What is the greenhouse effect and how can it cause global warming?
- Greenhouse gases trap energy from the Sun as heat in the atmosphere, increasing the Earth’s temperature
- increase in levels of carbon dioxide (methane, CO2, water vapour)
How have greenhouse gases increased?
burning fossil fuels releasing carbon dioxide. Levels of methane also increase due to bacteria in paddy fields used to grow rice and by cows passing wind.
What is peer review?
scientists checking the evidence for climate change to make sure there is no false claims and the research is valid -> reports in the popular media (newspapers) do not go through peer review -> oversimplified, inaccurate or biased info
impacts of deforestation and global warming
- destruction of many animals’ habitats, releases large amounts of greenhouse gases, reduces biodiversity
- increased sea levels, more severe weather, change of distribution of animals such as insects, increased melting of polar ice sheets/glaciers
reduces habitat -> reduces biodiversity
Programmes to maintain biodiversity
1. breeding programmes
to stop endangered species becoming extinct, animals are bred in captivity to make sure it survives if species dies out in the wild.
Programmes to maintain biodiversity
- breeding programmes
- Protection and regeneration of rare habitats, such as coral reefs
- Reintroduction of field margins and hedgerows
- Governments reducing deforestation and carbon dioxide emissions
- Recycling resources instead of dumping waste in landfills
Programmes to maintain biodiversity
3. Reintroduction of field margins and hedgerows
in agricultural areas where farmers only grow one type of crop. Farmers leave field margins (a strip of land around fields) where wild plants and animals can live. They also plant hedgerows between fields. Hedgerows and field margins provide a wider variety of plants and animals, preserving the biodiversity
Programmes to maintain biodiversity
4. Governments reducing deforestation and carbon dioxide emissions:
using renewable sources to generate electricity -> reducing global warming
Programmes to maintain biodiversity
5. Recycling resources instead of dumping waste in landfills
recycling -> less waste in landfills -> fewer habitats are destroyed -> positive effect on biodiversity
Conflicts on preserving biodiversity
- expensive, such as paying farmers to reintroduce field margins and hedgerows
- damage to people’s income, reducing deforestation is positive for biodiversity, but people in the tree-felling industry could be unemployed
- conflict between preserving biodiversity and food security. Sometimes pests are killed by farmers to protect crops so more food can be produced. In this process, biodiversity is affected.
positive human interactions with ecosystems
- maintaining rain forests, ensuring habitats here are not destroyed
- reducing water pollution and monitoring the changes over time
- replanting hedgerows and field margins to provide habitats which were previously destroyed
negative human interactions with ecosystems
- production of greenhouse gases leading to global warming
- producing sulfur dioxide in factories, leading to acid rain and affects habitats
- clearing land to build on, reducing the number of habitats
what are the biological factors affecting levels of food security?
- increasing birth rate threatens food security in some countries
- changing diets in developed countries -> scarce food resources transported around the world
- new pests and pathogens that affect farming
(pests eat food crops and pathogens cause infectious diseases) - environmental changes impacting food production; lack of rain -> widespread famine in some countries
- cost of agricultural inputs - modern farming requires lots of resources (fertilisers & pesticides & food for livestock). resources become more expensive as population increases -> some countries can’t afford -> threatens food security
- conflicts that affect availability of food and water in some places of the world (war -> farming disrupted and imports of food unavailable -> and reduce the reliable supply of water
what is food security?
having enough food to feed a population
What are sustainable methods of food production and why is it important?
Sustainable food production is making enough food without using resources faster than they renew
It is important because it means enough food can be made to feed everyone
How can the efficiency of food production be improved?
And why does this work?
by reducing energy transfer from food animals to the environment -> done by limiting movement (of livestock) & controlling temperature of surroundings
This works because less energy used for moving and controlling body temperature -> more energy available for growth -> more food produced
what is factory farming
biomass is used to provide energy for respiration and movement
livestock like calves and chickens can be factory farmed, raising them in small temperature controlled sheds -> small means limited chicken movement
being kept in warm conditions and having their movement restricted means less biomass is wasted (reduces energy transfer) compared to free-range chickens - grow more eggs and grow faster
ethical objections to factory farming
- animals are so close together -> infectious diseases can spread more easily - treated w/ antibiotics to stop this
- stressed, more likely to fight
ethical - think that animals should be raised in natural conditions and be able to engage in normal behaviour