Ecological relationships and energy flow Flashcards
What is a population?
The number of organisms of the same species living in the same area
What is a habitat?
The area where a population lives
What is a community?
A group of populations living in habitats close together
What is biodiversity?
The measure of the number of different species living in the area
What is the environment?
The conditions which surround and effect an organism in their habitat
What is an abiotic factor?
A non-living factor such as temperature, humidity, light intensity
What is a biotic factor?
A living factor such as the effect of a predator on its prey
What is an ecosystem?
An area in which a community of organisms interact with each other and their physical surroundings
What is sampling?
A process used to give a good estimate of the number, or percentage cover, of an organism in a particular area
What is a quadrat?
A square frame used as a subsection for sampling
What is number sampling? When is it used?
Counts the number of organisms in a sample. Used when the number of individuals is easy to determine
What is percentage cover sampling? When is it used?
Measures the percentage area an organism or individual covers in a sample. Used when it is difficult to determine where one individual stops and another one starts
What is random sampling? (3)
- Drawing samples from an area at random intervals.
- Carried out when the area is uniform.
- Enough samples should be used to give a representative sample of an area and quadrats should be positioned using random numbers to avoid bias.
What is belt transect sampling?
Sampling using quadrats placed at regular intervals. Used when zonation is present
What is competition in animals usually for? (4)
Food, water, territory, and mates
How can competition occur?
When a number of animals or plants have to compete for the same desired resources
What is competition in plants usually for? (5)
Light, carbon dioxide, water, minerals and space
What is a food chain?
A sequence of organisms which feed off each other, passing nutrients and energy
What is a food web?
A number of interlinked food chains
What is a producer in a food web?
An organism that produces, a plant, which is at the start of a food chain
What is a consumer?
An animal that gains its food from consuming other organisms
What do the arrows in a food chain represent?
Energy flow
What are trophic levels? (2)
- The level at which an organism feeds in a food chain or web
- The different stages of the feeding process in a food chain or web
What is the source of energy in a food chain?
The sun
What is a pyramid of numbers?
A diagram showing the numbers of organisms at each stage (trophic level) of a food chain
What is a pyramid of biomass?
A diagram showing the mass of living tissue, biomass, at each stage of a food chain
Why are pyramids of numbers and biomass referred to as a pyramid?
The number of organisms usually decreases with increasing trophic level
Why is a pyramid of numbers not accurate?
Many small organisms could feed off of one big one such as 5mm long insects feeding off a single 100m tall tree
How is energy lost at each trophic level? (3)
- Not all the available food is eaten (skeleton, fur)
- Not all the food is digested, some is egested as faeces
- Energy is lost as heat in respiration
What is competition?
The ‘battle’ between living organisms for the same resource or resources
What is a nutrient cycle?
The cycling of substances in the environment
What is a decomposer?
An organism which breaks down the tissues of dead organisms and excretory products
What is decomposition?
The breaking down of dead organisms into small pieces
What do fungi and bacteria do in the decomposition process?
Breaking down the organic compounds into their simplest components, which plants can absorb and use again
What is meant by the term saphrophyte?
A bacterium or fungus which decomposes material by releasing enzymes onto the surface and absorbing the breakdown products
What is humus?
The organic content of the soil formed from decomposing plant and animal material
What are the optimum conditions for decomposition? (3)
- A warm temperature
- Adequate moisture
- A large surface area in the decomposing organism
What is the carbon cycle?
The cycling of carbon-containing substances in the environment
What are the main processes in the carbon cycle? (6)
- Photosynthesis
- Feeding
- Respiration
- Decomposition
- Fossilisation
- Combustion
What processes have added to the increase of carbon dioxide in the atmosphere, and what is a result of this?
Combustion and deforestation have allowed the carbon dioxide concentration to become unbalanced as more carbon dioxide is being given off than can be taken in
How does carbon dioxide assist global warming?
Carbon dioxide and other gases in the atmosphere create a ‘greenhouse blanket’ which traps the heat from the sun within the atmosphere
What are the effects of global warming? (5)
- Climate change
- Polar ice caps melting
- Increased sea levels and flooding
- More land becoming desert
- Loss of habitats
What can be done to lessen the effects of global warming? (3)
- Plant more trees
- Reduce deforestation
- Burn fewer fossil fuels (use more efficient fuels)
What are the three parts of the nitrogen cycle?
- Nitrification
- Nitrogen fixing
- Denitrification
What is nitrification?
The process by which ammonia is converted to nitrates
What are nitrifying bacteria?
The bacteria which converts ammonia to nitrates
What are nitrogen fixing bacteria?
A special group of bacteria that can convert nitrogen gas into nitrates
Where can nitrogen fixing bacteria be found?
In nodules in the roots of legumes (such as peas, beans and clover)
What is nitrogen fixation?
A process which allows bacteria to change nitrogen gas into nitrates
What are denitrifying bacteria?
Bacteria that convert nitrates into atmospheric nitrogen
How can the processes of nitrification and nitrogen fixation be accelerated? (2)
- Higher temperatures
- Aerated soil
Where are denitrification bacteria most commonly found?
In waterlogged soils
What are the 3 beneficial bacteria for the nitrogen cycle?
Also
What is the negative bacteria for the nitrogen cycle?
Beneficial:
- nitrifying
- nitrogen-fixing
- decay
Negative:
- denitrifying
Why is soil more fertile when legumes (peas, beans, clover etc) are grown? (3)
- legumes contain nodules in their roots which contain nitrogen-fixing bacteria
- which converts Nitrogen gas to Nitrates
- which fertilises the soil
What is meant by the term decay? (2)
- saprophytic digestion via decomposers (decay bacteria and fungi)
- which convert dead organic matter to ammonia
(Preceded by breakdown by detritivores)
