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1.2 Ecosystems
• Ecosystem – a part of a biome in which abiotic (non-living)
factors interact with biotic (living) components
– Can be many hectares of land, or the size of an old log.
• Within an ecosystem, there are many habitats.
• A habitat is where an organism
lives.
The habitat of the red fox often
includes the edges of forests or
marshlands
There are all sorts of different
‘habitats’ that different
species occupy:
• The Blind Flatworm
shrimp
Live in dark caves. They are
called “troglobites” (cavedwellers). They have adapted to
darkness - do not require eyes...
White-Spotted Puffer Fish
• Lives in coral reefs (in tropical waters)
Second most poisonous vertebrate in
the world...
It’s muscles, skin, liver and ovaries
contain toxin 3x deadlier than cyanide.
The Rattle Snake
Occupies different habitats depending on
the time of year...
SUMMER
WINTER
Open grassland (areas
with high rodent
density)
Hibernating dens (rock
fissures or caves)
Abiotic Interactions in Ecosystems
• It is the abiotic components that allow the biotic
components to survive in an ecosystem.
– Abiotic factors include :
• Oxygen - produced by green plants & microorganisms.
• Water - necessary for all life.
• Nutrients - for growth.
• Light - required for
photosynthesis.
• Soil - contains water &
nutrients. Home to
many plants & animals.
Biotic Interactions in Ecosystems
• Community: all organisms that interact within an
ecosystem.
• Population: all members of a certain species within
an ecosystem.
• Species: all organisms within an ecosystem that have
the same structure & who can
reproduce with each other (and
produce fertile offspring).
Biotic Interactions in Ecosystems
• Species can have many types of relationships in a
population.
– Symbiosis refers to the interaction between the members
of two different species.
• Commensalism - one species benefits, one is not
affected
For example, the barnacles on a whale
• Mutualism - both species benefit
For example, a bee gathering nectar from a flower
• Parasitism - one species benefits, the other is harmed
For example, hookworm living in dogs
COMMENSALISM
(Biological hitch-hiking)
The Imperial shrimp hitches a ride
on a large sea cucumber. It rides
along through areas of potential
food, at no cost to the other
organism.
Anyone home?
The pearlfish is a small fish (5-10cm) that lives
inside a seacumber in the day and at night, exits
through the anus of the seacumber to feed.
MUTUALISM
• Leaf Cutter Ants
Cut the leaf..
These ants
cultivate (grow)
a fungus. They
feed the fungus
and the fungus
serves as their
food!
Teachers' Domain: Ancient Farmers of
the Amazon
Chew into a
pulp
Store the pulp
with ant feces
and fungus
spores
Fungus begins
to grow...
MUTUALISM
LICHEN = algae + fungus
The algae provides
food (glucose) for
the fungus
through
photosynthesis.
PARASITISM
HOOK WORMS
A parasitic worm that
lives inside the
intestines of its host
(mammal). These
worms such blood from
the host’s intestinal
walls ...this leads to
anemia (iron
deficiency).
M
O
U
T
H
The common way for hook worms to enter
is through the skin (walking barefoot)...
PARASITISM
• The Pine Beetle
The pine beetle has
infested lodgepole
pine trees in BC’s
Central Interior.
Burrows in the
tree, feeds on
trees phloem
(nutrients) and
lays its eggs.
Provincial Exam Question
Provincial Exam Question
Niches, Competition and Predation
• Niche: the role an organism has within an ecosystem.
– also refers to the environment in which a species prospers
• Competition: occurs when a limited resource is desired by 2
or more individuals in a niche.
– this limits the size & health of individual
organisms, & perhaps the population .
• Predation: the relationship between the
“eaters” & the “eaten”.
– Predators have adaptations to help them catch prey.
– Prey have adaptations to help avoid predators.
• Eg. spines & shells, camouflage and mimicry.
Provincial Exam Question
Biodiversity in Ecosystems
• Biodiversity: the variety & number of different
individuals & species in an ecosystem.
– Healthy ecosystems generally have high biodiversity.
– Most biodiversity losses occur from the loss of habitat.
– Humans often have a negative
impact on biodiversity.
– Ecological management
programs try to balance
human progress with
maintaining biodiversity.
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