Ecology and Environment Flashcards
Define a Habitat
The place where an organism lives (field)
Define a Population
All the organisms of one species in a habitat
Define a Community
All the different species in a habitat
Define a Ecosystem
All the organisms living in a particular area and all the non-living (abiotic) conditions (temp,climate)
Investigate the population size of an organism
- Place 1m^2 quadrat randomly in area
- Count organism cover in quadrat
- Repeat the experiment 10 times
- Work out average of all calculations
Define Biodiversity
Variety of different species of organisms on Earth or within an ecosystem
How do Abiotic factors affect communities
- Environmental conditions - light intensity (plants) , moisture level and soil pH
- Toxic chemicals - Excess fertilisers in lakes cause eutrophication = death of organisms
How do Biotic factors affect communities
- Availability of food
- Number of predators
- Competition
Define a Producer
Make their own food using energy from sun (food chain start with a producer)
Arrangement of a Food Chain:
- Producer are eaten by primary consumers
- Primary consumers eaten by secondary consumers
- Secondary consumers eaten by tertiary consumers
Define Decomposers
- All of food chain eventually die and eaten by decomposers
- Decomposers break down dead material and waste
Why is only 10% of energy transferred from one trophies level to another?
- Some parts of food not energy or excreted
- Used for staying alive (respiration)
- Transferred to surroundings by heat
What is the Carbon Cycle
- Plants and animals decompose, they broken down by microorganisms (bacteria)
- Microorganisms = Decomposers
- Decomposers release CO^2 back into air by respiration
What is the Nitrogen Cycle
- Decomposers -turn nitrogen to ammonia
- Nitrifying bacteria-Turn ammonium ions in decaying matter into nitrates
- Denitrifying bacteria-Turn nitrate back into N^2 gas
How is Acid Rain caused?
- Burning of fossil fuels releases CO2 and sulfur dioxide (coming from sulfur impurities) into the atmosphere
- When gas mixes with rain clouds it forms dilute sulfuric acid
- This then falls as acid rain
- Internal combustion engines in cars and power stations are main cause of acid rain
How is Acid Rain harmful?
- Cause lake to become more acidic, many organisms are sensitive to changes in pH and many plants and animals die
- Kills trees, acid damages leaves and releases toxic substances from soil, making it hard for trees to take up nutrients
How is carbon dioxide a source of a Greenhouse has?
- Burning of fossil fuels
* Slash and burn forest clearance
How does methane act as a source of a greenhouse gas?
- Generated by bacteria in anaerobic (low O2) conditions
* e.g. Bactria in waterlogged paddy field for rice cultivation give off methane
How does nitrous oxides act as a source of a greenhouse gas?
Burning fossil fuels
How does CFCs act as a source of a greenhouse gas?
- Used in aerosol sprays - deodorants or fridges
* Damage ozone layer that prevents UV radiation from reaching the Earth
What is the greenhouse effect?
- Increasing carbon dioxide in atmosphere and CFCs and Nitrous oxide - enhanced greenhouse effect
- Earth is heating up (global warming), climate change lead to rising sea, flooding leading to habitat loss and reduce in crop growth
How is Carbon Monoxide Caused?
- Fossil fuels burnt without enough air supply - produce gas carbon monoxide
- Poisonous - prevents red blood cells from carrying oxygen
- Released in car emissions
How is Eutrophication caused?
- Nitrates and phosphates onto fields as mineral fertilisers
- If too much fertiliser applied and it rains, nitrates leached into rivers and lakes
- Result is eutrophication
How can Eutrophication cause damage to river and lake ecosystems?
- Fertilisers enter water add extra nutrients
- Cause algae to grow fast and block out light
- Plants can’t photosynthesise due to lack of light and die
- Microorganisms that feed on dead plants increase in number and use up all oxygen in water
- Organisms that need oxygen (fish) die
What are the affects of Deforestation?
- Leaching
- Soil Erosion
- Disturbing Evapotranspiration
- Disturbing Balance of Carbon Dioxide and Oxygen
What is Leaching and how does Deforestation affect it?
- Trees take up nutrients from soil before washed away (leached) by rain, but return to soil when leaves die
- Trees removed = nutrients get leached away, but not replaced
- Leaving infertile soil
How does Deforestation affect Soil Erosion?
- Tree roots hold soil together
- Trees removed = soil washed away by rain (eroded)
- Leaving infertile ground
What is Evapotranspiration and how does Deforestation Disturb it?
- Evapotranspiration is process of water evaporating from earth surface and from plant transpiration
- This water falls back to earth as rain
- Trees removed = Evapotranspiration reduced
- Local climate drier
How does Deforestation Disturb the balance of Carbon Dioxide and Oxygen?
- Forests take up CO2 by photosynthesis, store it in wood, slowly release when they decompose
- Trees removed = stored carbon released at once as CO2, disturbs Carbon cycle and contributes to global warming
- Also, less photosynthesis takes place, releasing less oxygen - oxygen level in atmosphere drops
