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ECOSYSTEMS, BIODIVERSITY,
BIOACCUMULATION,
BIOMAGNIFICATIONS
Biosphere
 The area of earth that can support life is called
the Biosphere. The biosphere is composed of
 Lithosphere: solid part - km’s below the
earth’s surface
 Atmosphere: gaseous part  1-2km above the
earth (spores/bacteria) surviving here
 Hydrosphere: liquid part  7-10 km deep
(includes all fresh and saltwater on earth)
Biomes
 Within the Biosphere, smaller areas known as
Biomes exist.
 Biome Examples: Desert, Arctic, Grassland,
Scrub Forest, Rainforest, Arid Rainforest,
Taiga, Savannah, Ocean, Fresh Water
Ecosystems
 Going even smaller, we have what are known as Ecosystems.
This level is where the study of ecology begins to become
manageable.
 An ecosystem can be various sizes, but is generally somewhat
distinct from the Biome proper.
 Possible ecosystems: Fresh water lake, swamp, coniferous
forest, rotting log, forest floor, a single cedar tree
 - Within an ecosystem, there are both living and non-living parts.
 Living. The living organisms Biotic part  ants, trees, snakes,
bush pigs, sloth etc.
 Non Living. water, sunlight, oxygen, soil, nutrients, temperature
Abiotic Part
Habitats and Niches
 Each organism has a
place in which it
physically lives. This is
known as the
organism’s Habitat.
 e.g. centipedes inhabit:
Undersides of fallen
leaves
 - The combination of the
job an organism does
(what it eats/what
benefits it provides) and
where it lives is known as
the organism’s Niche.
 e.g. centipede’s niche:
Living under leaves,
eating dead plant
matter and insects.
Generally there is only
one organism per niche.
 Organism Niches:
 Squirrel: Live in tree,
harvest acorns
 Sloth: Live in tree, eat
leaves, feed tigers
Biodiversity:
 When one species of organism becomes
dominant, it reduces the amount of other types
of species in an ecosystem. This is bad for the
ecosystem
 Reasons: Every organism in an ecosystem fills
an important niche. The loss of even the most
seemingly insignificant organism can have
unpredictable effects farther up the food
chain.
 Ecosystems become more fragile if they have
less species in them. Think disease epidemic,
pollution, flooding etc.
Bioaccumulation &
Biomagnifications
 There are two basic terms we are discussing
here.
 Bioaccumulation: The absorption of synthetic
chemicals into a food chain.
 Biomagnification: The increase in
concentration of that chemical as you go up a
food chain.
 E.g. the amount of mercury in parts per million
(concentration) in minnows will be dwarfed by
the amount in full grown trout.
Bioaccumulation
 We are concerned about these phenomena because
together they mean that even small concentrations
of chemicals in the environment can find their way
into organisms in high enough dosages to cause
problems.
 For Bioaccumulation to occur pollutant must be:
 1. Long Lived - If a pollutant is short-lived, it will be
broken down before it can become dangerous.
 2. Mobile – Must be able to get into an organisms
tissues - If it is not mobile, it will stay in one place and
is unlikely to be taken up by organisms.
 3. Fat soluble – water soluble chemicals would
pass out of the body in the urine. Fat soluble
chemicals stay put in the body’s fat. - If the
pollutant is soluble in water it will be excreted by
the organism. Pollutants that dissolve in fats,
however, may be retained for a long time.
 4. Biologically Active – Causes harm to the
organism that eats it. E.g gold is not biologically
active and will not harm an organism if ingested
in small amounts. Mercury is biologically active
and will cause the brain of the organism harm.
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