7.2 Organisation of Ecosystems Flashcards
Define population
A species that occupy the same habitat.
Define habitat
The place in which an organism lives.
Define community
Populations of different species interacting.
Define ecosystem
The interactions between the biotic and abiotic factors in an area.
What do food chains show?
Food chains show the feeding relationships of different organisms and the flow of energy between the organisms.
Define biomass
The total mass of living material
What are trophic levels?
The stages in a food chain.
What do arrows in a food chain represent?
The direction of biomass transfer.
Describe a simple food chain
Producer - primary consumer - secondary consumer - tertiary consumer
What is a producer?
An organism that makes its own food.
What types of organisms are primary producers?
Photosynthetic organisms like green plants and algae that trap energy from the sun.
What is a primary consumer?
An organism that feed on producers.
What is a secondary consumer?
An organism that feeds on primary consumers.
What is a tertiary consumer?
An organism that feeds on secondary consumer.
What is a predator?
A consumer that kills and eats other animals.
What is prey?
An animal that is killed and eaten by another animal.
Describe the pattern of predators and prey in a stable community
The number of predators and prey rise and fall in cycles
Why are producers the trophic levels?
- Producers provide all biomass for food chain (production of glucose via photosynthesis)
- The rest of the food chain involves the transfer of the biomass
What piece of apparatus is used to measure the abundance and distribution of organisms in an area?
Quadrat
What piece of apparatus is used to study the distribution of organisms across a gradient?
Bell transect
When considering the abundance of organisms what is meant by the term mean?
The average number of organisms.
How is arithmetic mean calculated?
Sum of each number of each organism/the total number of each type.
When considering the abundance of organisms. what is meant by the median?
The organism that represents the middle value when the number of each organism are arranged from lowest to higher.
When considering the abundance of organisms. what is meant by the mode?
The most populous organisms
Describe how materials cycle through the living and non-living components of an ecosystem
- Organisms take in elements from their surrounding e.g. soil, air
- Elements converted to complex molecules which becomes biomass
- Elements transferred along food chains
- Elements returned to environment during excretion and decomposition of dead animals
Give 3 molecules which are cycled through ecosystems.
Oxygen, carbon dioxide and water.
Describe the carbon cycle
- Plants fix carbon dioxide into organic molecules during photosynthesis
- The organic carbon-containing molecules are passed onto organisms that eat the plants
- Carbon dioxide is released back into the atmosphere by respiration from animals and plants
- Burning fossil fuels also releases carbon dioxide into the atmosphere
Why is the carbon cycle important?
Carbon-containing molecules such as glucose are important for living organisms to grow and provide energy for vital functions within cells.
Describe the water cycle.
- Water from lakes and oceans evaporates
- The evaporated water condenses into clouds and returns to the earth as precipitation.
- The water from precipitation is useful for life on land
- The water then returns to rivers and oceans through surface runoff
Why is the water cycle important?
Living organisms require water and the water cycle provides organisms on land with a continuous supply of water
Why are microorganisms important for the cycling of materials through an ecosystem?
Microorganisms (bacteria and fungi) return carbon to the environment by releasing carbon dioxide through reparation while they decompose dead matter. The decomposition of dead matter in soil returns mineral ions to the environment for other organisms to use e.g. plants use mineral ions for growth.
How can different temperatures be bad for certain communities?
- If the temperature is too low, growth will be slower as organisms will use more energy to stay warm.
- If the temperature is too high, organisms can die and water will become limited as evaporation increase
What detrimental impacts can sulfur dioxide have on the environment?
- Formed when fossil fuels containing impurities are burnt
- Sulfur dioxide can dissolve in water to form acid rain which can erode buildings an pollute water sources
What is detrimental impacts can carbon monoxide have on the environment’s?
- Carbon monoxide is formed from the incomplete combustion of fossil fuels.
- Carbon monoxide binds irreversibly to haemoglobin which prevents it from carrying oxygen
- Too much exposure can cause unconsciousness and death
Name 5 greenhouse gases
- Water vapour
- Carbon dioxide
- Nitrous oxide
- Methane
- CFCs
Give 3 human activities that contribute to greenhouse gases.
- Burning fossil fuels
- Deforestation
- Large scale livestock farming
How do greenhouse gases lead to global warming?
- Greenhouse gases allow heat from the sun to enter the atmosphere.
- The gases act as a blanket and tray heat in the atmosphere.
State 3 negative consequences of global warming
- Sea level rise caused by melting icebergs.
- Disrupted farming and agriculture
- Increased spread of diseases in warmer climates
