3.2.1 Functioning Ecosystems Flashcards
Understand the format of a food chain
*levels in a food chain are called trophic levels
Understand how energy is transferred through a food chain
Producers first get their energy from the sun (heat energy) then primary consumers eat the producers and energy is then passed on through chemical energy
-Chemical energy is stored in BIOMASS
On average how much energy is transferred when a species eats another?
Approx. 10%
Why is only a fraction of energy passed on, where does the rest go?
Energy is used by each trophic level and transforms into either stored energy (fat in cells) to be used in metabolic activities (daily life of that species). The rest is excreted (through waste, contributing to the nitrogen cycle) or released in respiration (contributing to the carbon cycle).
What assumptions need to be made in the lincoln index
-all individuals in a given area have an equal chance of being captured (sampling must be random
-
Define Biomass
Biomass is the dry weight of all organic matter contained in each trophic level of a food chain
What is the Lincoln Index
N= (Mxn)/m
(estimates a population size)
where:
M= number of individuals caught, marked and released intially
n= number of individuals caught on second sampling
m= number of individuals that were recaptured that were already marked
Understand the purpose of the water cycle and how it works
- collects, purifies and redistributes earth’s fixed water supply
- 90% of water vapour on land results from plant transpiration
Understand the purpose of the carbon cycle and how it works
- large quantities stored in carbon sinks (ocean, fossil fuels underground, plants, atmosphere)
- CO2 enters an ecosystem through photosynthesis and is then converted by autotrophs
- eaten by consumers through the food chain and then released through respiration
- biomass (fossils from dead animals) will turn into carbon
Understand the purpose of the nitrogen cycle and how it works
- all living things need N and essential for proteins and amino acids
- 80% of the atmosphere is N
- needs to be fixed in ecosystem via bacteria or converted nitrate
- ammonification: nitrogen is fixed into ammonia by bacteria in living modules on the roots of legumes
- nitrification: ammonia is converted into nitrate by other bacteria
- N is passed on through the food chain eventually ending up with decomposers where
- dentrification: soil bacteria break down ammonia and release nitrogen into the atmosphere
What is a niche
- A species role and position in its environment. A species interactions with the biotic and abiotic factors of its own environment. Additionally, a species affect other species in regard to taking up food and resources, and being a vital part in the food web
- Each species fits into an ecological community in its own unique way and has its own tolerance ranges for various environmental factors
What is the difference between a fundamental and a realised niche?
- Tolerance range represents the fundamental niche of a species
- realised niche of a species is narrower than this because of competition with other species
What is the difference between intraspecific and interspecific competition?
Intraspecific is competition between the same species, interspecific is competition across 2 or more species
What is a keystone species?
Keystone species are species that have a disproportionately large effect on its’ ecosystem by controlling the population of other species, maintaining the biodiversity with no species dominating.
Understand the competitive exclusion principile
There is too much competition in a habitat if there are 2 species with identical niches
Similar niches may be able to survive, if the species evolve
Analyse data to identify species in an Australian ecosystem that are keystone species, and recognise their niche and the effects of removing this from an ecosystem
*This is a worksheet skill
On elearn
Where does solar energy go?
Radiation, reflection off earth and absorption into plants (to create energy)
