ecosystems Flashcards
succession definition
a series of changes that occur to an environment and its’ organisms present in the area over time
niche definition
an organisms role and interaction within its ecosystem
biomass definition
amount of material produced by an organism which can be transferred as energy
humus definition
dead organic matter from plants/animals death and secretion
pioneer plants
first plants to appear in succession, their growth and death adds humus, retaining water, heat and nutrients
2 differences between primary and secondary succession
- primary is new land, secondary is previously inhabited land that has been destroyed
- secondary is faster
competitive exclusion principle
idea that 2 species occupying an identical niche cannot coexist indefinitely due to competition for food/shelter/minerals etc
climax community
the result of succession when a community becomes stable. is called a plagioclimax when formed through human intervention
what are 2 biotic factors
intraspecific and interspecific competition
intraspecific
competition between members of the same species
interspecific
competition between members of different species
what are prey predator oscillations
prey causes predators ⬆️
when predators ⬆️ prey ⬇️
prey ⬇️ so predators ⬇️ and the cycle repeats
what are abiotic factors
non living
climate factors
light temp and humidity
edaphic factors
ph, soil temp and texture
topography
the gradient and 02 concentration in ponds
how to measure as estimate of temperature changes
with temperature proxies such as the hockey stick graph
why is there yearly fluctuations of CO2
- natural temp
- energy used
- time of year = photosynthesis
why is methane dangerous
- more potent than CO2
- breaks down into carbon and water vapour
how to estimate population size with grids
mean density per quadrant X total area
/
area of each quadrant
how to use ice cores in estimating temp
analyse air trapped in layers as 02 isotopes reflect temp
using radiocarbon dating in estimating tempt
- carbon isotopes
- peat bogs with the plants and pollen grains to understand climate lived in
impact of climate change: rainfall
- warm air traps more water vapour
- causing droughts or flooding
impact of climate change: ice melting
- sea levels rising
- water temps rise
- changes enzyme activity, animals may migrate
- land can be out underwater
impact of climate change: enzyme activity
- can cause infertility
- eggs may not hatch due to metabolic rate being too high/low
impact of climate change: species distribution
other countries then have ideal temperatures for other animals causing migration - problem in insects as increases transmission of insect bourne disease
how farming affects ecosystems
-crops removed and burned = less recycling of nitrogen, more carbon in air
- monocultures deplete minerals in soil
- artificial fertilisers = don’t support humus and soil structure (drainage etc)
how fishing affects ecosystems
- too many fish caught, can’t repopulate esp if in breeding season
- large nets can accidentally kill wrong species, can destroy habitats
3 appendices of CITES
i - trade of organisms banned
ii - animals at risk (extinction and endangerment) have grads controlled
iii - trade is only regulated in specific regions
what are losses in energy transfers
muscle movement and metabolic reactions (heat)
faeces (undigested food)
respiration
problems with number pyramids to represent ecosystems
- hard to estimate
- organisms are diff sizes
- organisms have diff life cycles
problems with biomass pyramids to represent ecosystems
- must be killed for dry biomass
- time consuming
- different components have different energy levels
gross primary productivity
total light energy fixed by photosynthesis - plants use 25% for own needs
net primary productivity
energy available for the next organism, relies on biotic and abiotic factors
role of buffer strips
- contain diff species to increase biodiversity and provide protection
- combats affect of monocultures depleting resources
trophic levels
number of times energy has been transferred
detrivores
ingest deed organic material
saphrotrophs
- secrete defective enzymes and digest products
what does nitrifying bacteria do
oxidises ammonium compounds to form nitrates
role of nitrogen fixing bacteria
in soil or root nodules
converts nitrogen into ammonia
denitrifying bacteria
breaks down nitrates for production of ATP (NADP) and releases nitrogen gas as waste
role of lightning in nitrogen cycle
when it strikes it transfers nitrogen from air to soil
how is carbon removed from air and water
photosynthesis of plants and algae
transfer of carbon in living things
through respiration, feeding, death and excretion
role of fossilisation in carbon cycle
- traps carbon in fossil fuels
- released via combustion
role of sedimentation in carbon cycle
- carbonate rocks
- released with weathering and volcanic activity
how efficiency of energy changes in different trophic levels
- different animals use different amounts of energy
- energy is lost in animals via faeces, heat loss and respiration
- not all of animals are consumed
role of fungi in ecosystems
are decomposes that crate more biological humus and aid in nutrient and nitrogen recycling
