Ecology and the Environment Flashcards
What is ecology?
The study of how organisms affect each other and are affected by other factors in the environment
What is an ecosystem?
The interaction of living (biotic) and non-living (abiotic) factors in a particular place e.g. rainforest
What is a habitat?
The place where a community of organisms live e.g. a pond or meadow
What is an environment?
The non-living (abiotic) factors in an area e.g. soil type, temperature
What is a species?
One type of organism that can reproduce to give fertile young e.g. bull frog
What is a population?
All of one species in a habitat e.g. number of bull frogs in a pond
What is a community?
All of the living organisms that live in one habitat e.g. the frogs, the carp and the kingfishers all living in the pond
What does biodiversity mean?
The variety of different species of organisms on Earth, or within an ecosystem
Why is a high biodiversity important?
It makes sure that ecosystems are stable, because different species depend on eachother for food and shelter
What are the different abiotic factors that affect communities?
- Environmental conditions e.g. light intensity, moisture level, soil pH
- Toxis chemicals e.g. chemical pesticides or fertilisers
What biotic factors can affect communities?
- Availability of food e.g. an increase in berries could lead to an increase in blackbirds
- Number of predators e.g. the number of lions decreases the number of gazelles
- Competition e.g. organisms competing with eachother for the same resources
What are the trophic levels in food chains?
Producers
Primary Consumers
Secondary Consumers
Tertiary Consumers
What does each bar show on a pyramid of numbers?
The number of organisms at that stage of the food chain
What does each bar show on a pyramid of biomass?
The mass of living material at that stage of the food chain
(how much all the organisms at each level would ‘weigh’ if you put them all together)
What does each bar show on a pyramid of energy transfer?
Show the energy transferred to each trophic level in a food chain (always in a pyramid shape)
Identify the process labeled A
Combustion -> The burning of fossil fuels
Identify the process labeled B
Respiration (by plants)
Identify the process labeled C
Photosynthesis
Identify the process labeled D
Decomposition
Identify the process labeled E
Respiration (by animals)
Identify the process labeled A
Nitrogen Fixation
Identify the process labeled B
Decomposition -> Carried out by bacteria and fungi
Identify the process labeled C
Nitrification
Identify the process labeled D
Absorption of fertiliser/nitrates
Identify the process labeled E
Denitrification
Why is nitrogen needed for plants and animals?
To make amino acids, which make proteins. These are needed for growth
What elements are found in proteins/amino acids?
CHON
(Carbon, Hydrogen, Oxygen, Nitrogen)
What is nitrogen fixation?
The process of turning nitrogen (gas from the air) into nitrogen compounds (like nitrates/nitrites)
What are the two ways nitrogen fixing happens?
Lighting -> The energy from a bolt of lightning makes nitrogen react with oxygen to form nitrates
Nitrogen-fixing bacteria
What are the four bacteria involved in the nitrogen cycle?
Decomposers
Nitrifying bacteria
Nitrogen-fixing bacteria
Denitrifying bacteria
What do decomposers do in the nitrogen cycle?
They break down proteins (in rotting plants/animals) and urea (in animal waste)
They then turn it into ammonia which then forms ammonium ions in the soil
What do nitrifying bacteria do in the nitrogen cycle?
Turn ammonium ions into nitrites (NO2 -), and then nitrates (NO3 -)
What do nitrogen-fixing bacteria do in the nitrogen cycle?
Turn atmospheric nitrogen gas into nitrogen compounds that plants can use
What do denitrifying bacteria do in the nitrogen cycle?
Turn nitrates back into nitrogen gas (don’t like it)
In what type of soil do de-nitrifying bacteria thrive?
Waterlogged
Where can nitrogen-fixing bacteria be found?
Free-living in the soil
Root nodules of leguminous plants (e.g. beans, clover, peas etc)
Why should farmers avoid growing the same crop in a field every year?
Because that crop would use up the same minerals and ions, and they would never be replenished
How would a crop rotation system using clover increase crop yields?
Clover is a leguminous plant with nitrogen-fixing bacteria in its root nodules
The nitrogen-fixing bacteria will release nitrates into the soil
The nitrates can then be used to make plant proteins which leads to more plant growth
Why is Carbon Monoxide (CO) poisonous?
It combines with haemoglobin in red blood cells, which prevents them from carrying oxygen
How is acid rain created?
Sulfur dioxide comes from impurities in the fossil fuels
When this gas is mixed with rain clouds, it forms dilute sulfuric acid
This then falls as acid rain
What are the main causes of acid rain?
Internal combustion engines in cars
Power stations
Why is acid rain bad for the environment?
Can cause lakes to become acidic which causes many organisms to die
Can kill trees. The acid damages leaves and releases toxic substances from the soil
What environmental issues are caused by climate change?
Extreme weather
Rising sea levels and flooding -> melting ice caps
How is carbon dioxide released into the atmosphere?
Combustion (burning fossil fuels)
Deforestation (less trees to take CO2 in from the atmosphere)
How is methane released into the atmosphere?
Produced naturally (e.g. from rotting plants)
Rice-growing
Cattle rearing
How is methane released into the atmosphere?
Produced naturally (e.g. from rotting plants)
Rice-growing
Cattle rearing
How is nitrous oxide released into the atmosphere?
Released naturally by bacteria in soils and the ocean
A lot is released from soil after fertiliser is used
How does eutrophication happen?
Fertilisers enter the water, adding extra nutrients
The extra nutrients cause algae to grow fast and block out the light
Plants can’t photosynthesise due to lack of light and start to die
With more food available (dead plants), microorganisms increase in number and deplete all the oxygen in the water
Organisms that need oxygen die
How does deforestation affect the environment?
Leaching
Soil erosion
Disturbing evapotranspiration
Disturbing the balance of carbon dioxide and oxygen
What is leaching?
Rain washing away (leaching) nutrients from the soil
How do trees stop leaching?
Trees take up nutrients from the soil before they can be leached, but returns them to the soul when leaves die
Why does leaching increase after deforestation?
When trees are removed, nutrients get leached away but don’t get replaced, leaving infertile soil
How do trees prevent soil erosion and what happens when they are cut down?
Tree roots hold the soil together
When trees are removed, soil can be washed away by the rain (eroded), leaving infertile ground
How do trees maintain the balance of carbon dioxide and oxygen?
Forests take up CO2 by photosynthesis and store it in wood
Trees slowly release CO2 as they decompose
What happens to the balance of CO2 and O2 when trees are cut down?
Fewer trees means less photosynthesis which leads to more CO2 and less O2 in the atmosphere
When trees are burned, they release CO2. This disturbs the carbon cycle and contributes to global warming
What is evapotranspiration?
Both the processes of water avaporating from the Earth’s surface and plant transpiration.
This water falls back to the Earth as rain
How does deforestation disturb evapotranspiration?
When trees are cut down, ev
