Recycling within ecosystems Flashcards
1
Q
What type of recycling is necessary?
A
- nutrients
- in order for plants and animals to grow
- used up by living organsism
- no large external energy source repleneshing nutrients in the way the sun supplies energy
2
Q
What is a decomposer?
A
- an organsims that feeds on and breaks down dead plant or animal matter, thus turning organic compounds into organic ones (nutrients) available to photossyntehtic producers in the ecosystem
- primarily microscopic fungi and bacteria - can be larger
- they are saprotrophs
3
Q
How do decomposers consume food? How do they receycle
A
- secreting enzymes onto dead organisms or organic waste matter
- break down complex organic molc into smaller simpler soluble molecules
- then absorbed
- then releases stored inorganic compounds and elements back into the environment
4
Q
What are detritivores?
A
- another class of organism involved in decomposition
- speed up decay process by feeding on detritus - dead and decay material
- break it into smaller pieces of organic material, which increases SA for decomposer to work on
- e.g. woodlice
- internal digestion
5
Q
What is nitrogen used for? How is it ingested
A
- amino acids
- and consequenctly proteins
- nucleic acids
- animals
- food
- plants
- absorbed from environment
6
Q
How is nitrogen taken up by plants?
A
- N2 needs to be combines with other elements
- bacteria convert niutrogen into a useable form
7
Q
What is nitrogen fixation?
A
- combines atmospheric nitrogen with hydrogen to produce ammonia
- form of nitrogen that can be used by plants
8
Q
What are the two examples of nitrogen fixing bacteria? How do they do it?
A
- contain enzyme nitrogenase
-
Azotobacter
- free-living soil bacterium
-
Rhizobium
- live in root nodules
- growths on the roots of leguminous plants
9
Q
How do the bacteria have symbiotic mutualistic relationship with the plant?
A
- plant gains amino acids from Rhizobium, which are produced by fixing nitrogen gas in the air into ammonia in the bacteria
- bacteria gain carbohydrates produced by the plant during photosynthesis, which they use as an energy source
10
Q
What is nitrification>
A
- process by which ammonium compounds in the soil are converted into nitrogen-containing molecules that can be used by plants
- free-living bacteria in the soil called nitrifying bacteria are involved
11
Q
How does nitrification occur? WHat are the steps?
A
- oxdiation reaction
- and so only occur in well-aerated soil
- nitrifying bacteria (e.g. Nitrosomonas) oxidise ammonium compounds into nitrites
- NO2-
-
Nitrobacter (another genus of nitrifying bacteria) oxidise nitrites to nitrates
- NO3-
- NO3- is highly soluble, and therefore the form in which most nitrogen enters the plant
12
Q
When does denitrification occur? What happens
A
- in absence of oxygen (e.g. waterlogged soil), denitrifying bacteria convert nitrates in the soil to nitrogen gas
- only occur in anaeobic conditions
- bacteria use nitrates as energy source for respiration
13
Q
What is ammonificiation?
A
- Name given to the process by which decomposers convert nitrogen-containing molecules in dead organisms, faeces, and urine into ammonium compounnds
14
Q
How do carbon dioxide levels change?
A
- photosyntehsis does not happen at night but respiration is constant
- fossil fuelds
- deforestations
15
Q
why is important ammonia is converted to nitrate
A
absorbed by root hair cells to make amino acids
