Ecosystems Flashcards
What is an ecosystem
A community of animals, plants and bacteria interrelated with the physical and chemical environment
What are the components of an ecosystem
- habitat
- population
- community
What is a population
All the organisms of one species, who live in the same place at the same time and who can breed together
What is a community
All the populations of different species, who live in the same place at the same time and who can interact with each other
What is an organisms niche
The organisms role in an ecosystem
Examples of biotic factors that effect ecosystems
- producers
- consumers, primary consumers
- decomposers
- mates
- food availability
Abiotic factors that affect ecosystems
- pH
- temperature
- humidity
- shelter
- weather
What type of changes in ecosystems effect population size
- cyclic changes
- directional changes
- unpredictable/erratic changes
What are cyclic changes
- repeat themselves in rhythm
- movement of tides
- change in day length
- predator and prey fluctuate
What is a directional change
- go in one direction
- tend to last longer than the lifespan of an organism
- erosion of a coastline
- deposition of silt in an estuary
What are unpredictable or erratic changes
- no rhythm or constant direction
- effects of lightening or hurricanes
What are the different types of energy loss
- chemical: not all of an organism being eaten/ingested
- heat: respiration
- movement/kinetic
What are the three different types of pyramid
- biomass
- number
- energy
What is the formula for biomass transfer
Efficiency = (biomass of a higher Trophic level) / (biomass of a lower Trophic level) x100
What is GPP
Gross primary productivity
- the rate at which plants convert light energy into chemical energy through photosynthesis
What is NPP
Net primary productivity
- the energy that is given to the next Trophic level
What is the formula linking GPP, NPP and R
GPP - R = NPP
Environmental factors that are manipulated to make energy conservation more efficient
- light levels
- drought-resistant crops
- greenhouses: higher temperatures
- better nutrients
- pests
- fungal diseases
- competition for light from weeds
Ways humans can make energy transfer from producers better
- harvesting animals just before adulthood
- selective breeding
- antibiotics
- giving the animals their food. Not making them hunt for it
Examples of decomposers
- bacteria
- fungi
What are the steps of saprotrophic decomposition
- saprotrophs secrete enzymes onto dead and waste material
- enzymes digest the material into smaller molecules.
- saprotroph’s absorb molecules into their bodies
- molecules are stored or respired to produce energy
What is a climax community
The final stable community that exists after the process of succession has occurred
What is succession
The progressive change in a community of organism over time
What is a pioneer species
The species that begin the process of succession, often colonizing an area as the first living things there
What are the different types of succession
- primary
- secondary
What is primary succession
Starts with a bare rock or sand
- behind a retreating glacier
What is secondary succession
Starts with existing soil, clearing of vegetation
- after a forest fire
What is deflected succession
When something happens that stops succession from continuing to the next stage
- if grazing continued the grass would be the climax community
What are the different stages of succession
- pioneer stages
- intermediate stages
- climax community
What happens at the climax community
- increased biodiversity
- increase in food web complexity
- increased stability
What happens to organisms as they go through the stages of succession
The outcompete the previous species in the area
What happens to matter in biomass transfer
- cycles
- earth is a closed system
- measured in kg
- solid, liquid, gas
What happens to energy in biomass transfer
- flows
- earth is an open system
- measured in joules
- heat, light, kinetic, chemical
What are the different types of pyramids in ecosystems
- numbers
- biomass
- energy transfer
What is the pyramid of numbers
- width of each bar represents the number of organisms at each Trophic level
- producers are at the bottom
What is the pyramid of biomass
- width shows the mass of dry organic mater (biomass)
What is the pyramid of energy transfer
- width represents the amount o energy passed through each level
Which pyramids always have a pyramidal shape
- biomass
- energy transfer
What are the different stages of the nitrogen cycle
- nitrogen fixation
- nitrification
- assimilation
- ammonification
- denitrification
what happens in nitrogen fixation
- nitrogen gas is turned into ammonium ions
- by nitrogen fixing organisms
What happens in nitrification
- ammonium ions are oxidised to nitrate ions
- nitrifying bacteria
What is assimilation
- using digested molecules to form other molecules
What is ammonification
- process of converting energy from urea into ammonia
What is denitrification
- nitrate ions are reduced by bacteria in anaerobic condition
- made into dinitrogen
Examples of nitrogen fixing bacteria
- azotobactar
- rhizobium
Where is azotobacter found
Soil around the roots
Where the rhizobium bacteria found
Inside the roots
What are examples of nitrifying bacteria
- nitosomonas
- nitrobacter
Where are nitrosomonas and nitrobacter found
In the soil
What do the nitrifying bacteria do
- oxidisation
- turns ammonia into nitrates
Formula for nitrogen gas
N2
Formula for nitrate ions
NO3-
Formula for ammonium ions
NH4+
What does nitrogen fixing bacteria convert
Nitrogen gas —> ammonium
What does nitrifying bacterial convert
Ammonium —> nitrates —> nitrates
What does denitrifying bacteria convert
Nitrates —> nitrogen gas
Examples of carbon sources
- farmland
- deforested areas
Examples of carbon sinks
- peat bog
- ocean floor
- immature woodland
Examples of carbon neutral
- mature woodland
What is a natural climatic climax
The only climax community possible in a given climate
- no humans
What is a plagioclimax
Community maintained at pre-climax stages by constant human interference
What is Inter specific competition
Between members of different species
What is intra specific competition
Between members of the same species
What are k-strategist population sizes
- limiting factors exert more of an effect as the population grows closer to the carrying capacity
- gradually levels out
- low development/reproduction rate
- large life span/body mass
What are r-strategist population sizes
- population size increases rapidly, exceeding the carrying capacity
- not enough resources to survive
- “boom and bust”
- high development/reproduction rate
- mall body mass/life span
What is the competition exclusion principle
- two organisms wont inhabit the same niche
- thrive separately but not together
- one outcompetes the other
What are density dependent factors
Biotic factors
- finding a mate
- predation
What are density independent factors
Abiotic factors
- light
- territory
- temperature
- oxygen availability
What is carrying capacity
Species average population size in a particular habitat
What is preservation
- leaves ecosystems untouched
- no human interference
What is conservation
- active measure to maintain biodiversity
- requires human presence for sustainable management and restoration
What does CITES stand for
Convention of international trade in endangered species of wild fauna and flora
What do CITES aim to do
Ensure that the international trade of wild animals and plants does not threaten the species survival
What does IUCN stand for
International union for conservation of natures
What are the aims of the IUCN
Inform and catalyze action for biodiversity
what are the categories of the IUCN red list
- least concern
- near threatened
- vulnerable
- endangered
- critically endangered
- extinct in wild
- extinct
What is reclamation
Restoring ecosystems that have been damaged or destroyed
What is coppicing
- trunk cut close to the ground
- new shoots grow from cutting
- cut and grown again
- allows for faster growth
What is a positive of coppicing
Carbon is stored in wood
- able to store more as wood grows
What are the different types of felling
- clear
- selective
- strip
What is clear felling
Cutting all trees in an area
What is selective felling
Cutting down mature, diseased or unwanted species/trees
What is strip felling
Cutting small patches or strips of trees
Ways to manage overfishing
- zones where fishing is banned
- limited number of boats
- banning fishing at certain times
- rules of types of fishing equipment
- inspecting fishing catches
- releasing young fish
Wha is an ecosystem approach
Understanding the structure and dynamics of the whole ecosystem
What is sustainable development
Management of ecosystems so that natural resources can be used without running out
