B18 Biodiversity and ecosystems Flashcards
1
Q
What is an ecosystem?
A
The interaction of a community of living organisms with biotic and abiotic elements of their environment
2
Q
What is an organism?
A
An individual animal or plant
3
Q
What is a population?
A
The number of individuals of the same species living in a certain habitat
4
Q
What is a community?
A
A group of interdependent living organisms in an ecosystem
5
Q
What is a biotic factor and state some examples?
A
Living conditions e.g. the number of predators, availability of food, new pathogens etc
6
Q
What is an abiotic factor and state some examples?
A
Non-living conditions e.g. soil pH, water levels, oxygen levels, temperature etc
7
Q
What is a producer?
A
A photosynthetic organism that uses the sun’s energy to convert biomass into glucose by photosynthesis
8
Q
What is a consumer?
A
An organism that eats other organisms
9
Q
What is biodiversity?
A
The variety of all the different species of organisms on earth, or within an ecosystem
10
Q
Explain why a high biodiversity ensures the stability of ecosystems
A
- Each species may have a different function that contributes to the survival of other organisms in that ecosystem and themselves
- Greater range and availability of food and prey to eat, species are not dependent on just one species for food
- High biodiversity ensures the stability of ecosystems by reducing the dependence of one species on another for food, shelter and the maintenance of the physical environment
- Protects them from any changes in a given ecosystem
11
Q
Explain why biodiversity plays a critical role in sustaining human populations
A
- Humans depend on biodiversity for sustained food growth, for clean air and water and for medicine and shelter
- Humans use the Earth’s resources, fossil fuels to generate electricity, for transport, and to make materials such as plastic, mineral from rocks and soil to grow food
12
Q
Explain how the human population has affected our land
A
- Vast areas of land are dug up for quarries to obtain rocks and metal ores
- This reduces the land available for other organisms
- Humans reduce the amount of land available for other animals by building, farming, quarrying and dumping waste
- Toxic chemicals from industrial waste poison the soil
- Landfill sites and sewage can pollute the soil
- Deforestation leads to flooding
13
Q
Explain how the human population has affected biodiversity
A
- More and more land is used for building houses, shops, industrial sites and roads on
- This destroys the habitats of other living organisms and reduces biodiversity
- The waste produced by humans pollutes the environment and processing it takes up land, affecting biodiversity
- Pollution reduces biodiversity
14
Q
Explain how the human population has affected natural resources
A
- The huge human population drains the resources of the Earth
- People are readily using up finite reservers of metal ores and non-renewable energy resources such as crude oil and natural gas that cannot be replaced
15
Q
Explain how the human population has affected our air
A
- More and more air pollutants are released such as dust, which cause global dimming
- Carbon dioxide and sulphur dioxide both cause acid rain
- Smog causes respiratory problems
16
Q
Explain how the human population has affected water
A
Eutrophication and bioaccumulation
17
Q
What are the reasons for population explosion?
A
- No natural predators
- Better living conditions and education
- Less infectious disease and better healthcare
- Growing lots of food, the ability to farm intensively
18
Q
What have been the effects of this rapidly rising population on the Earth’s resources?
A
- Raw materials are rapidly being used up
- Increasingly more waste is produced
- Unless waste is properly handled more pollution will be caused
- Habitats are being destroyed for building requirements of human population
19
Q
Give two reasons why using herbicides can reduce biodiversity
A
- Reduces plant life
20
Q
What are bioindicators?
A
An organism used as an indicator of the quality of an ecosystem, especially in terms of pollution
21
Q
State two substances that can pollute the air when they are released in the atmosphere
A
- Carbon dioxide
- Sulphur dioxide
22
Q
State two ways that water can become polluted
A
- The runoff of chemicals from farmland (eutrophication)
23
Q
Name some greenhouse gases
A
Methane, water vapour and carbon dioxide
24
Q
Name an acidic gas that can lead to acid rain
A
Sulfur dioxide
25
Name an effect of acid rain
- Water pollution
- Increases the acidity of water (lakes and ponds)
- Corrodes limestone e.g. sculptures
- Kills vegetation
26
Name the cause of smog
- Nitrogen oxides that react with sunlight
- VOCs that are released from gasoline
27
Why might it take a long time for bioaccumulation effects to be seen?
Not all animals are eaten
28
What are the three main reasons for deforestation?
- Provide land for cattle, for the beef market
- To grow staple foods such as rice, or making cheap food int developed world such as palm oil
- Grow crops that can be used to make biofuels based on ethanol
29
What is deforestation?
The destruction of woodlands/forests by cutting down trees
30
What issues arise from deforestation?
- Less biodiversity
- Increased carbon dioxide levels
- Leaching and soil erosion
- Disturbance of water cycle
- Reduced photosynthesis due to loss of carbon sink
- Micro-organisms feeding on decaying vegetation release carbon dioxide
31
How does deforestation affect biodiversity?
- Habitats like forests can contain a huge number of different species of plants and animals
- When they are destroyed in deforestation, there is a danger of many species becoming extinct and biodiversity is reduced
32
How does deforestation affect carbon dioxide levels?
- Deforestation increases carbon dioxide levels in the atmosphere
- Cutting down loads of trees means that the amount of carbon dioxide removed from the atmosphere during photosynthesis is reduced
- Trees 'lock up' some of the carbon that they absorb during photosynthesis in their wood, which can remove it from the atmosphere for hundreds of years
- Removing trees means that less is locked up
- Carbon dioxide is released when trees are burnt to clear land
- Microorganisms feeding on bits of dead wood and decaying vegetation releases carbon dioxide during respiration
33
Suggest and explain two harmful effects on the environment caused by the destruction of large areas of trees
- Increases carbon dioxide levels
- Less carbon is absorbed by the trees and taken out of the atmosphere by photosynthesis
- Carbon that is locked up inside these trees is released when the trees burn as carbon dioxide
- Micro-organisms feeding on bits of dead wood also releases carbon dioxide during respiration
- This increases carbon dioxide levels in the atmosphere and contributes to global warming
- Reduces biodiversity as habitats are destroyed and can increase the chance of certain species becoming extinct
34
What is food security?
Having enough available, affordable and nutritious food to feed a population
35
Explain the factors affecting food security
- The increasing birth rate has threatened food security in some countries
- Changing diets in developed countries means scarce food resources are transported around the world
- New pests and pathogens that affect farming
- Environmental changes that affect food production, such as widespread famine occurring in some countries if rains fail
- The cost of agricultural inputs
- Conflicts that have arisen in some parts of the world which affect the availability of water or food.
36
Explain how cost of agriculture affects food security
- Scientists have produced crops genetically engineered to withstand droughts or floods, or increase yield
- This has increased the cost of the seed
- Fears that people that need these most are unable to afford them
- sImilarly, irrigation systems, fertilisers, pesticides, all cost money, thus reducing food security for some
37
Explain how conflicts affect food security
- Conflict almost always leads to an increase in food insecurity
- During war, there is an extended lean season: food shortages can turn into famine
- Spring, violence prevents planting
- Summer, no crops growing so stores are depleted
- Fall, little to harvest and fighting closes markets
- Winter, food runs out and no seeds are prepared
38
Explain some solutions to food insecurity
Sustainable food production
- maintaining soil quality so plants grow well year after year
- more efficient ways to produce food
- allow continued production/harvesting e.g. taking care of fish stocks in our oceans so they do not run out
Alternative sources
- microbiology
- insects
39
What is sustainability?
The avoidance of the depletion of natural resources to maintain an ecological balance
40
Describe how the efficiency of food production can be improved
- Limiting movement, so that they use less energy moving around
- Controlling temperature, livestock are kept at their optimum temperature so that they use less energy regulating their body temperatures themselves
- Prophylactic antibodies, prevent the risk of infection
- Controlled lightning, used to make livestock sleep for longer (reduced movement)
- Controlled feeding (high protein), modified food, use of growth hormones, to increase growth
41
Why are certain fish stocks in the ocean decreasing?
- Better technology of fishing vessels, they are bigger and are able to travel further
- They also have more efficient ways of catching the fish
- Overfishing
42
What methods can be taken to make fishing more sustainable?
- Imposing restrictions on fishing
- Increased size of holes in the nets to only catch bigger fish
- Smaller, younger fish are not caught
- Restrictions on amount (quotas)
43
Explain how fish farming is made more efficient
- Fish are increasingly farmed to protect wild stocks, which have fallen sharply due to overfishing
- They are kept in cages, fed a high protein
- They grow quickly but there are obvious ethical concerns
44
What is mycoprotein?
Produced from the Fusarium fungus, which grows and reproduces rapidly using cheap sugar syrup in fermenters
45
What are disadvantages of intensive farming methods?
- Some people believe them to be unethical
- Diseases spread more rapidly
- Antibiotics can build up in the food chain, over use of antibiotics
- Increased use of fossil fuels for heating
46
Suggest two reasons why it is more efficient to rear cows indoors than to rear cows outdoors
- Warmer indoors so less energy wasted in keeping warm
- Less movement indoors so less energy wasted
47
Explain how the intensive farming of pigs increases the efficiency of food production
- The pigs are kept inside or in a temperature controlled environment
- They are also kept enclosed or in a restricted environment
- So less energy is lost in controlling body temperature
- Less energy used for movement
- So more energy is available for growth
- Less energy is transferred to the surroundings
