B19 - Human influences on ecosystems Flashcards
What is a Biotic environment? Give some examples. [2]
- Living
e.g.
Predators, food, mates
What is an Abiotic environment? [2]
- Non-living
What are 2 factors of an abiotic environment? [2]
- Physical
- Climatic
Give examples of abiotic physical things. [2]
- Oxygen and carbon dioxide concentration
- Light intensity
- Water availability
Give examples of abiotic climatic things. [1]
- Temperature
-Humidity
What is an ecosystem? [2]
A unit containing all of the organisms in a community and their environment, interacting together.
What is a population? [2]
A group of organisms of one species, living in the same area at the same time.
What is a habitat? [1]
The place where an organism lives.
What is a community? [1]
All of the populations of all the different species in an ecosystem.
What interaction is an ecosystem made from? [2]
The community of organisms in a habitat (all the organisms)
&
The abiotic factors (physical environmental factors)
What is biodiversity? [2]
The range and variety of different species of organisms on Earth, or within an ecosystem
What are some human activities that are reducing biodiversity? [3]
- Waste production
- Deforestation
- Global warming
What are some varieties of life on Earth that biodiversity refers to? [3]
- The number of different species in an area
- The range of different types of organisms
e.g. plants, animals and microorganisms = number of different species - The genetic variation within species (how many different gene versions there are)
THE GREATER THESE ARE, THE GREATER THE BIODIVERSITY!
Where would you find high biodiversity? [1]
Rainforests
Where would you find low biodiversity? [2]
- Arctic
- Deserts
- Cities
How do we measure biodiversity? [2]
- Counting the number of different species in a given area
- Counting the total number of individuals in a given area of ecosystem
What reduces biodiversity? [2]
Dominance of a species, monoculture, overharvesting, climate change, pollution.
What are the 3 main reasons for habit destruction? [3]
- Clearing land for farming and housing
- Extraction of natural resources
- Marine pollution
What are 5 pollutants in freshwater pollution? [5]
- Untreated sewage
- Chemical waste
- Discarded rubbish
- Fertilisers
- Insecticides & herbicides
What is ‘EUTROPHICATION’? [2]
When a body of water becomes overly enriched with nutrients. Less oxygen levels.
What are pesticides? [1]
- Poisonous chemicals which kill pests.
- Can be harmful for the environment
Where are insecticides kept in the body? [1]
Fatty tissue
Why is ‘clearing land for farming and housing’ causing habitat destruction? [2]
- Crops, livestock and homes take up a big amount of space
- Increasing population and demand for food = amount of land must increase to allow these things to happen. Hence clearing habitats (deforestation)
Why is ‘extraction of natural resources’ causing habitat destruction? [2]
- Natural resources like wood, stone and metals are used to make different products.
- Many trees are cut down to get these products - which lead to habitat destruction and a clearing of a large space e.g. mining
Why is ‘marine pollution’ causing habitat destruction? [4]
- Oil spills and other waste pollutes the ocean, killing sea life.
- Human activities lead to this.
- Eutrophication can happen when fertilisers from farmed fields enter waterways.
- This causes a huge decrease in biodiversity in these areas since most species living in these waterways die from lack of oxygen.
What is the cause and effect of ‘untreated sewage’ in water. [3]
Cause:
- Lack of sewage treatment is planted in area because of lackof money which leads to sewage running into streams/rivers.
Effect:
- Good source of food for bacteria which increase quickly
- Bacteria use the oxygen dissolved in the water (they respire aerobically) and cause deaths of aquatic organisms like fish = eutrophication.
What is the cause and effect of ‘chemical waste’ in water. [3]
Cause:
- Chemicals (e.g. mercury) can be released from factories into rivers/oceans or spread into the land surrounding the factory.
Effect:
- Heavy metals do NOT break down and so they can build up in food chains = bioaccumulation, and poison the top carnivores
What is the cause and effect of ‘discarded rubbish’ in water. [3]
Cause:
- Much rubbish consists of plastic that is either discarded or buried in landfills.
Effect:
- Plastic is non-biodegradable and remains in the environment for hundreds of years.
- Animals can eat this plastic as it breaks down into smaller pieces (especially in the ocean) and gets into food chains.
What is the cause and effect of ‘fertilisers’ in water. [3]
Cause:
- Runoff from agricultural land if applied in too high a concentration.
Effect:
- Causes rapid increase in algae which then die
- Good source of food for decomposing bacteria which increase rapidly
- They use the oxygen dissolved in the water (they respire aerobically)
- This causes the death of aquatic organisms like fish = eutrophication. since lack of oxygen.
What is the cause and effect of ‘insecticides and herbicides’ in water. [3]
Cause:
- Sprayed on crops to prevent damage by insects and growth of weeds
Effects:
- Bioaccumulation, loss of biodiversity, damage to beneficial insects, can build up in soil to toxic concentrations and harm other organisms.
What is ‘DEFORESTATION’? [1]
The clearing of forests
What are the 4 effects of deforestation? [4]
- Extinction
- Loss of soil
- Flooding
- Increase of carbon dioxide in the atmosphere
What is the explanation and consequence of ‘extinction’ [3]
Explanation:
- Forests can contain a wide variety of different plant and animal species
- When these habitats are destroyed there is a big risk of many species becoming extinct.
Consequence:
- As a habitat is destroyed it causes a loss of large numbers of plant and animal species.
- Many of these species are only found in these areas and so it will become extinct.
What is the explanation and consequence of ‘loss of soil/soil erosion’ [3]
Explanation:
- When trees are removed there are no roots to stabilise the soil during heavy rain.
- Soil is easily washed away and nutrients are lost.
- This makes it harder for new trees to grow later.
Consequence:
- Trees will usually take up nutrients and minerals from the soil through their roots.
- Without trees, nutrients and minerals will remain unused in the soil and will be washed away into rivers and lake by rain (leaching).
What is the explanation and consequence of ‘flooding’ [3]
Explanation:
- Trees slow down rain as it falls to the ground because the rain hits leaves first.
- The water can then be absorbed by the soil then the roots.
Consequence:
- Without trees the topsoil will be loose and unstable so it will be easily washed away by rain.
- Increasing the risk of flooding and landslides.
What is the explanation and consequence of ‘increased carbon dioxide in atmosphere’ [3]
Explanation:
- Photosynthesis removes carbon dioxide from the atmosphere and stores it in trees.
- The carbon dioxide is released back into the atmosphere when trees are burnt to clear land.
Consequence:
- Less oxygen released and less carbon dioxide removed
- Burning trees further contributes to global warming.
What are the 4 ways to conserve endangered species? [4]
- Education
- Seed Banks
- Captive breeding programmes
- Monitoring and protecting species and habitats
How does ‘education’ conserve endangered species? [3]
- Teaches people about the natural world.
- Helps them understand the importance of conservation.
- Tells them what they can do to help.
How do ‘seed banks’ conserve endangered species? [3]
- Seeds of endangered plant species are kept in a seed bank.
- Place where the conditions are good to keep the seeds alive for a long time.
- This protects and saves genetic diversity in plants.
How do ‘captive breeding programmes’ conserve endangered species? [4]
- This is where animals are bred in captivity (e.g. zoos)
- It helps prevent endangered species from going extinct.
- Easier for animals to increase their numbers - less infant mortality (deaths) so more offspring live to reproduce.
- Some animals may be released to the wild to re-establish a population - this can help to make sure the species survives if it dies out in the wild.
How does ‘monitoring and protecting endangered species’ conserve endangered species? [3]
- Helps scientists understand what species are most under threat.
- Protected areas are set up (national parks) to protect the organisms and habitats.
- Development (making stuff) is banned in this land (e.g. houses, farming)
What is an endangered species? [1]
When a species is considered to be at a high risk of extinction.
What is extinction? [1]
When no individuals of a species remain.
What are 5 factors that cause organisms to become endangered? [5]
- Climate change
- Habitat destruction
- Hunting
- Pollution
- Introduced species
How does ‘climate change’ affect organisms? [3]
- All organisms have an ideal temperature range. - If they can’t adapt to changing temperatures or other environmental conditions quickly enough they can become extinct.
- Global warming is causing the Earth to heat up.
How does ‘habitat destruction’ affect organisms? [2]
- As a species’ habitat is destroyed, fewer organisms can be supported.
- As their numbers start to decrease the species becomes endangered.
How does ‘hunting’ affect organisms? [3]
- Many species are hunted for e.g. fur, food or medicines.
- If endangered species are hunted they can easily become extinct.
- Endangered animals may also be killed by accident if hunters mistake an endangered species for a non-endangered species.
How does ‘pollution’ affect organisms? [1]
- Organisms can die, mistaking plastics/pollution for food
How do ‘introduced species’ affect organisms? [2]
- Introduced species become invasive
- Native species can’t compete with them or defend themselves.
