Ecology and the Enviroment Flashcards
What is habitat?
The place where an organism lives
What is population?
All the organisms of one species in a habitat
What is community?
All the different species in a habitat
What is an ecosystem?
All the organisms living in a particular area and all the non-living conditions
How can you estimate population sizes in different areas?
By using a quadrat
What is a quadrat?
A square frame
When using a quadrat, how can you make your results more accurate?
by using a bigger quadrat
What do food chains show?
Whats eaten by what in an ecosystem
What are the different stages in food chains called?
trophic levels
What do food chains always start with?
A producer, which makes it’s own food using energy from the sun
What are producers eaten by?
Primary consumers
What are primary consumers eaten by?
secondary consumers
What are secondary consumers eaten by?
tertiary consumers
What happens when all organisms die?
They get eaten by decomposers
What do decomposers do?
decompose dead material and waste
In pyramids of numbers, what does each bar show?
The number of organisms at that stage of the food chain
What does each bar on a pyramid of biomass show?
the mass of living material at that stage of the food chain
What is the source of energy for nearly all life on earth?
THE SUN
What is lost at each stage of the food chain?
material and energy
What percentage of energy is lost between each trophic level?
around 90%
How can you show how food chains are linked?
By drawing a food web
What does the carbon cycle show?
how carbon is recycled
What is the whole carbon cycle powered by?
photosynthesis
Animals and plants release CO2 back into the air by…
respiration
When plants and animals decompose, their broken down by..?
bacteria and fungi
Decomposition releases
CO2
When plant and animal products are burned, they release
CO2
Burning fossil fuels release…
greenhouse gases
What forms when sulfur dioxide mixes with rain clouds?
sulfuric acid
What are the main causes of acid rain?
Internal combustion engines in cars
Power stations
What affects can acid rain have on lakes?
Make it become more acidic
Severe affect on ecosystem
Many organisms are sensitive to changes in pH
They die
How can acid rain kill trees?
The acid damages leaves and releases toxic substances from the soil, making it hard for the trees to take up nutrients
Name four greenhouse gases
Carbon Dioxide
Methane
Nitrous Oxide
CFC’s
How do humans release carbon dioxide?
Car exhausts
Industrial processes
Burning fossil fuels
What human activity affects the level of carbon dioxide in the atmosphere?
deforestation
Where is methane produced naturally?
Rotting plants in marshland
Cows
What are the ‘man made’ sources of methane?
Rice growing
Cattle rearing
Where is Nitrous oxide released naturally?
By bacteria in soils and the ocean
What are CFC’s?
man-made chemicals that were once used in aerosol sprays and fridges
What do fertilisers cause when they leach into water?
Eutrophication
How exactly does eutrophication occur?
Nitrates and phosphates are put onto fields as mineral fertilisers
if too much fertiliser is applied and it rains afterwards, nitrates are easily leached into rivers and lakes
What damage can eutrophication do?
The extra nutrients can cause algae to grow fast and block out the light
So plants can’t photosynthesise due to lack of light and start to die
With more food available, microorganisms that feed on dead plants increase and deplete all the oxygen in the water
Organisms that need oxygen die
What four effects does deforestation have?
Leaching
Disturbing the water cycle
Soil erosion
Disturbing the balance of carbon dioxide and oxygen
What is Leaching?
When trees are removed, nutrients don’t get leached away, but don’t get replaced, leaving infertile soil
How does deforestation disturb the water cycle?
Increase surface runoff
The local climate can become drier as less transpiration happens
What is meant by soil erosion?
Trees bind soil together
When trees are removed, soil can be washed away by the rain, leaving infertile soil
How can deforestation disturb the balance of carbon dioxide and oxygen?
When trees are cut down and burnt, the stored carbon is released
Less photosynthesis takes place, so less oxygen is released, causing the oxygen levels in the atmosphere to drop
