Ecosystems/populations/sustainability Module 6 Flashcards
Habitat?
Place where an organism lives
Population?
All the organisms of one species in a habitat
Producer?
Organisms which produces organic molecules using sunlight energy
Decomposer?
An organism that breaks down dead or undigested organic materials
Trophic level?
A stage in a food chain occupied by a particular group of organisms
Ecosystem?
All the organisms living in a certain area, and all the non-living conditions found there
Dynamic system
Biotic factor?
Living features of an ecosystem
Abiotic factor?
Non living features of an ecosystem
How is energy transferred through an ecosystem?
Enters via photosynthesis
Plants store this as biomass
Energy passed on through organisms by eating each other
Why is not all energy passed on to the next trophic level?
Some of energy is never taken in, in the first place:
. Plants can’t use all light energy that reaches their leaves initially as some is wrong wavelength, reflected or passes through
Or light hits part of leaf which can’t photosynthesise
Some parts of organism aren’t eaten eg. bones or roots
Some parts are indigestible, forming faeces
Lost via respiration
Gross productivity?
The rest of the energy which is taken in (around 40%)
Net productivity?
The amount of energy available for the next trophic level
How do you find net productivity (biomass)?
gross productivity - respiratory loss
What do herbicides do?
Kill weeds that compete with agricultural crops for energy
What do fungicides do?
Kill fungal infections that kill crops
What do insectides do?
kills insect pests
What do fertilisers do?
chemicals that provide crops with minerals needed for growth eg. nitrates
How are intensive rearing livestock conditions controlled?
Animals kept in warm indoor pens, where movement is restricted, so less energy used moving around and keeping warm
Animals given food which is higher in energy than normal food
Describe the carbon cycle?
Carbon in form of CO2 in atmosphere is absorbed by plants when they carry out photosynthesis, becoming carbon compounds in plant tissues
Carbon passed on to animal consumers via feeding
All living organisms die and the Carbon compounds in the dead organisms are digested by micro organisms called decomposers, via saprobiontic feeding
Carbon returned to the air and water as all living organisms respire, including decomposers
However, if dead organic matter ends up in places where there aren’t any decomposers ( deep oceans or bogs), can be turned into fossil fuels ( heat and pressure over long time)
Carbon in fossil fuels released when they are burned = combustion
Other rocks formed from dead organic matter on sea floor, these rocks drawn down by tectonic plates, undergo chemical changes and release CO2, returned to atmosphere via volcanoes
Other rocks can also become land where they become chemically weathered and release CaCo3 ions into groundwater, which form the carbon containing rocks described above
Describe the Nitrogen cycle?
Nitrogen fixation
Ammonification
Nitrification
Denitrification
What’s Nitrogen fixation?
When Nitrogen gas in the atmosphere is turned into ammonia by bacteria such as Rhizobium and Azotobacter. The ammonia can then be used by plants
Also gets into system via lightening or fertilisers
Where’s Rhizobium found and it’s relationship?
Found inside root nodules of leguminous plants
Mutulastic relationship with the plants, as they provide plants with Nitrogen compounds, and they provide them with carbohydrates
Where do azobacter live?
Soil
What’s ammonification
When nitrogen compounds from dead organisms are turned into ammonia by decomposers, which go on to form ammonium ions
What’s nitrification?
When ammonium ions in the soil are changed into Nitrogen compounds which can then be used by plants (Nitrates)
First nitrifying bacteria Nitrosomanas changed ammonium ions into Nitrites
Then Nitobacter turns Nitrites into Nitrates
What’s denitrification?
When Nitrates in the soil are converted into Nitrogen gas by denitrfying bacteria, as they use Nitrates in soil for respiration, under anaerobic conditions
What’s succession?
Process in which an eco-system changes over time, biotic changes due to abiotic changes
What’s primary succession?
When there’s no soil, just start with bare rock
What’s secondary succession?
Happens on land which that’s been cleared off all the plants, but where all the soil remains eg forest fire
Describe succession?
New species colonies land = the pioneer species
Abiotic condition are harsh as no soil, only specialised pioneer species can grow
Pioneer species changes abiotic conditions as they die decompose and form soil
Conditions less hostile and more organisms grow, more soil forms
Species become outcompeted as ecosystem becomes more complex and biomass increases
Reaches Climax community
What’s the climax community?
An ecosystem which is supporting the largest and most complex community of plants and animals it can. It’s in a steady state
What’s a plagioclimax?
When human activities prevent from reaching normal climax
What’s deflected succession?
When succession prevented by human activity, but the plagioclimax formed is different to any of the normal stages
What is population size affected by?
Abiotic factos
Biotic factors- interspecific competition, intraspecific competition, predation
Describe interspecific competition?
Competition between different species
Reduced food sources
less food = less energy for growth and reproduction, both populations drop
Distribution affected, if ones better adapted other species will have to move
Think AC Milan vs INTER Milan
Describe intraspecific competition?
When organisms of same species compete with each other for food resources
Describe predation?
As prey pop increases, so does predators as there is more food, however more prey then eaten, so prey populations fall followed by predators
Carrying capacity?
Maximum stable population of a species that an ecosystem can support
Stages of population growth?
Lag phase
Log phase
Carrying capacity
Death phase
What’s conservation?
Protection and management of ecosystems so natural resources can be used without them running out
What’s reclamation?
Restoring ecosystems which have been damaged or destroyed
Preservation?
The protection of eco-systems so that they’re kept exactly how they are
How to manage woodland ecosystem in a sustainable way?
Trees cleared in small strips, grow back faster, and less soil erosion
Harvested via coppicing- cutting down trees in a way so can regrow, means don’t have to plant more
Plant only native tree species, aid ecosystem better
Planted trees attached to posts and glass tube, protecting them
Trees aren’t planted close together so don’t have to compete for resources
Fishing quotas?
international agreements put limits on the amount of certain fish species allowed to be caught, thrown back in sea dead or dying, as can’t be brought back
Problems are fish of wrong species still caught,
What does controlling mesh size of fishing nets do?
Reduces amount of unwanted fish caught accidentally, as bigger net size means will slip through
Also younger fish slip through net, allowing them to reach breeding age
