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The study of how living organisms interact with each other and with their environment.
Ecosystem = a natural unit of biotic components in a given area, as well as the abiotic factors with which
they interact. An ecosystem is major ecological unit.
Population= a group of organisms of a single species occupying a particular area
A community comprises of the different populations of species that live in that habitat
Habitat = particular area occupied by a population. Where an organism lives has biotic and abiotic
features which separate it from other habitats.
Microhabitat = small localities within a habitat, each with its own particular conditions.
Ecological Niche= the place of each species in an ecosystem
o Physical space it occupies
o Role it carries out within the community
o Its interrelationships with other species
In the long term, 2 species can't occupy the same niche in a specific habitat they would compete!
Biotic features= sum total of the organisms within the habitat and their interactions
Abiotic features include different types
o Edaphic features relate to soil includes all its physical and chemical characteristics
o Climatic features= light, temperature, moisture, salinity and especially, the stability/variability of these
The process by which organisms obtain energy to maintain life functions and matter to create and
Autotrophs convert simple inorganic materials, such as water and carbon dioxide, into energycontaining
complex organic compounds such as starch and protein.
Heterotrophs consume complex organic compounds such as starch and protein and break them down into
simple, soluble molecules e.g. Glucose and amino acids (which can be absorbed and built up into complex
Ultimate source of energy = sun= releases energy in form of electromagnetic waves
Not all solar energy that reaches Earth's atmosphere penetrates it can be reflected / absorbed / radiated back
into space by ozone layer, dust particles and clouds
90% of energy that reaches Earth's surface is reflected by vegetation, soil and water or absorbed and radiated
to the Earth's atmosphere as heat.
Only ~10% is left for producers to use only small part of total amount of energy reaching earth's atmosphere
enters ecosystems. Amount absorbed by plants varies by latitude
Only ~15% of energy entering a plant is utilised rest is lost by reflection / evaporation
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Energy flow through the ecosystem
Ecological energetics= the study of the flow of energy through the ecosystem
Energy from the sun
o Enters food chain at the producer level during photosynthesis
o Is the source of energy for the ecosystem
o Is passed from one trophic level to another through the ecosystem
o Passed along hierarchy of trophic levels with primary producers at the starting point
o Eventually the energy leaves the system as heat…read more