Transcript Biotic and Abiotic Influences on Ecosystems

Topic 2 - Biotic and Abiotic Influences on
Terrestrial and Aquatic Ecosystems
Biotic and Abiotic Influences on
Ecosystems
• Limiting Factor = any
factor that limits the
size of a population or
where it can live
• Tolerance Range = the
range of abiotic
conditions which a
species can survive
Abiotic Limiting Factors – Terrestrial
• Examples of how humans
affect abiotic factors in a
terrestrial ecosystem:
• Light
– Cutting trees to expose plants
underneath to more light
• Water
– Damming rivers decreases
water available
– Irrigating fields increases
water available in an
ecosystem
• Temperature
– Global warming
reduces habitat
for animals
adapted to cold
temperature
• Nutrients
– Adding fertilizer
to soil increases
available
nutrients
Abiotic Limiting Factors – Aquatic
• Examples of how humans affect
abiotic factors in an aquatic
ecosystem:
• Light
– Stirring up sediment at the
bottom of a lake decreases
amount of light reaching
plants
• Salinity (Salt Levels)
– Run-off from salting high
ways in the winter increases
salt concentration in rivers
and lakes
• Temperature
– Industries release
heated water into lakes
and rivers killing fish
and other organisms
• Nutrients
– Fertilizer can run-off
causing algal blooms
• Acidity
– Burning of fossil fuels
creates acid rain which
makes bodies of water
more acidic
Biotic Limiting Factors – Species Interactions
• Examples of biotic factors in
ecosystems:
– Competition
• Organisms compete for the
same limited resources: food,
water, habitat, light, mates
– Predation
• Predator (the organism that
hunts) kills and eats its prey (the
organism that is attacked)
• The populations of the predator
and prey depend on each other
(more on this topic next day…)
INSERT VIDEO LINK
A male lion with his cub eating a
water buffalo
Praying Mantis eating a
grasshopper
Indian python attempting to
swallow a deer
Lynx and a hare
Biotic Limiting Factors – Species Interactions
• Symbiotic Relationships
between organisms:
Flower provides the bee
with nectar, the bee helps
the flower spread its pollen
Mutualism (+ and +)
• Two organisms benefit from
each other
Orchids grow on the trunks or
branches of trees to receive more
light. As long as the plant is not
too heavy, the tree is not affected.
Commensalism (+ and 0)
• One organism benefits and
the other neither benefits nor
is harmed
Parasitism (+ and -)
• One individual lives on or in a
host organism and feeds on it
The cowbird lays their
eggs in the nests of
other birds (like the
reed warbler). The
reed warbler mother
must spend more time
feeding the larger and
more demanding
cowbird
Mutualism (+ and +)
Stinging anemone tentacles provide
the clownfish with protection from
predators. The clownfish defend
anemones against butterflyfish which
eat the anemones.
Bacteria live in the nodules of
legumes (ex. soybeans) and provide
nitrogen for the plant. The plant
provides sugars for the bacteria.
Cleaner wrasses and whale shark
Red-billed oxpecker and the Impala
Egyptian Plover and Nile crocodile
Cow (or other ungulates) and E.coli bacteria
Commensalism (+ and 0)
Shark and a remora fish
Ramora gets free ride + food
Buffalo and Cattle Egrets
Whales and barnacles
Parasitism (+ and -)
• Parasite receives nourishment from host
– Parasites don’t normally kill host but the host is
harmed
A roundworm inside a
person’s eye… EWWW!!!
Numerous roundworms from the bowel of a
dog post-surgery…. DOUBLE EWWW!!
Bed bugs… inside a mattress… do
you see the bed bug fecal
matter?!? EW!
Caribbean soldierfish host to a
parasitic isopod, which feeds on
its body tissues
Human head lice feeds on
blood from the scalp