Ecosystems Flashcards
(18 cards)
Describe the desired ecological equilibrium in a water system
We want a balance in time and space.
We want a balance of the total productivity of living organisms and the amount of death and decomposition.
We want a balance between photosynthesis (uses CO2 and releases O2) with respiration (releases CO2 and uses O2)
How is ecological equilibrium affected?
Changes seasonally and can vary along river length.
Pollution can cause unequilibrium / dead zones
What are the 2 sources of energy in water?
Primary producers i.e. the sun
Organic and inorganic material i.e. cells, proteins, amino acids, atoms
What is self-purification?
The ability of a system to increase activity at various trophic levels to deal with increasing organic matter etc.
What responds to inputs of pollution such as organic matter?
Only micro-producers can respond since they can increase feeding in short lifecycle.
Why is biodiversity important?
The more complex an ecosystem is the more stable it is in maintaining equilibrium.
What are properties of an ecosystem in a polluted river?
Low biodiversity and high biomass.
Produces conditions unsuitable for higher form of life.
What are the 5 major communities in aquatic ecosystems?
(list from bottom of food chain to top)
Phototrophic
Heterotrophic
Detrivores
Herbivores
Predators
Explain the role of the phototrophic community in aquatic ecosystems
Primary producers
Use photosynthesis to convert light to energy.
Exist as a periphytons (film on submerged solid surfaces) or phytoplankton (free living cells suspended in water).
Explain the role of the heterotrophic community in aquatic ecosystems
Micro-Consumers / Decomposers
Exist as bacteria, fungi, and protzoa.
Break down dead organic matter.
Exist everywhere and their presence can indicate recent pollution such as E-coli, Cryptosporidium and sewage fungus.
Why is bacteria important in terms of water quality?
They feed on biodegradable natural wastes of other living organisms, dead organisms, and biodegradable wastes released into water
What do aerobes require versus anaerobes?
What community are they a part of?
Aerobes require DO to oxidise food compounds.
Anaerobes make use of bound oxygen in organic salts or light energy.
Part of heterotrophic community.
Explain the role of the detrivore community in aquatic ecosystems
Consumers / Scavengers
Eat and break down dead bacterial material, feeding on non-living particulate organic matter.
Exist as collectors, shredders and scrapers (names represent how they feed themselves)
Explain the role of the herbivore community in aquatic ecosystems
Consumers
Eat living plants
Not many in aquatic ecosystems.
Piercers and shredders are 2 types (larvae and beetles)
Explain the role of the predator community in aquatic ecosystems
Consumers
Carnivores which eat organisms lower down food chain.
Exist at all levels from micro to macro invertebrates to fish,, birds and mammals.
How does fish presence indicate water quality?
Clean system is stable and has high biodiversity.
Fish require DO and DO reduces if there is high organic matter.
What happens between each trophic level in the food system? What does this mean for the ecosystems?
Whilst nutrients are recycled, the flow of energy is one way and energy is lost between each trophic level. Further away from input of energy the lower the amount of energy that will be available for the organism. This limits amount of trophic levels.
What type of systems are
a) rivers
b) lakes
What does this tell us?
a) heterotrophic
b) phototrophic
This tells us where most energy comes from
