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dynamic Ecology- the study of the
r a n ge i n s i z e relationships between organisms
and their environment
`all the living organisms that interact with each other in a
defined area and the non-living conditions, such as rainfall'
Large rock pools
Small areas of land
An oak tree
Particular stretch of a river
A playing field…read more

Slide 2

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6 Levels of Ecological Organisation
1. Individual: one organism, any type
2. Population: group of individuals, same species and living in the
same location
3. Community: group of organisms, different species but living in the
same location
4. Ecosystem: all of the living things in a given area that interact with
one another and also with their non-living environments
5. Biome: collection of the same ecosystems governed by a particular
set of environmental conditions
6. Biosphere: whole habitable surface of the Earth…read more

Slide 3

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Factors that Affect Ecosystems
Biotic Factors- living factors Abiotic Factors- non-living/physical factors
Competition Sunlight
Interactions e.g. prey and predators (predation) Rainfall
Faeces and urine Temperature
Honey and nectar Soil (edaphic)-pH, mineral ions, consistency, chemicals
Animals, plants, fungi Oxygen and water availability
Habitats, migration and hunting Climate, humidity and salinity…read more

Slide 4

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Biomass Transfer Through an Ecosystem
· The Sun is the source of energy for almost all ecosystems on Earth
Sun Photosynthesis Light energy converted into chemical
energy in photosynthetic organisms e.g. plants other
non-photosynthetic organisms as food
· Note, food webs: arrows represent direction of energy flow…read more

Slide 5

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Trophic Levels-
the level at which an organism feeds in a food chain (transfer of biomass and so
· 1st trophic level = producer an organism that converts light energy into chemical
energy by the process of photosynthesis
· 2nd trophic level = primary consumer
an animal that eats a producer Organisms that obtain their energy
· 3rd trophic level = secondary consumer by feeding on other organisms
· 4th trophic level = tertiary consumer
food chains rarely have more than a quaternary consumer as there is not
sufficient biomass and stored energy left to support any further organisms
· Decomposers break down dead organisms and release nutrients (molecules,
minerals and energy) back into the ecosystem
· Each trophic level is almost always less than the trophic level below as only a small
proportion of food they ingest is converted to new tissues mass, so only a bit of the
biomass is available for the next trophic level to eat…read more

Slide 6

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Measuring Biomass-
the mass of a living material present in a particular
· Pyramids of biomass areas of bars are proportional to the dry
mass of all the organisms at that trophic level
· Pyramids of energy burning the organisms in a calorimeter and
work out how much heat energy is released per gram- temperature
rise of a known mass of water Energy at each trophic level = kJm-2yr-1
^ allows for changes in photosynthetic Doesn't take
Discount production and consumer feeding patterns into account
water throughout the year seasonal
content as it changes
varies biomass present x total no. of organisms in each trophic level
each organism
· Dry mass 1) organisms killed 2) place in 80°C so all water is
evaporated 3) equation (green)
Gm-2 for land Gm-3 for water…read more

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