Download Community Relationships

Bellringer 12.3
Copy the following root words into your notebook.
• A- : without, not (ex: abiotic)
• Auto- : self (ex: autotroph)
• Bio- : life (ex: biology)
• Carn- : meat (ex: carnivore)
• Eco- : where one lives, home (ex: ecosystem)
• Herb- : plant (ex: herbivore)
• Hetero- : different (ex: heterotroph)
• -logy : study of (ex: biology, ecology)
• Photo- : light (ex: photosynthesis)
• -troph : to feed or eat (ex: autotroph)
• -vore : devour (eat) (ex: carnivore, herbivore)
Community Relationships
1. Symbiosis
A close relationship between two organisms of
different species in which at least one organism
benefits.
benefit is usually one of the following: food,
protection, habitat, or pollination
Includes: mutualism, commensalism, and
parasitism.
Mutualism (+,+)
Relationship in which both organisms benefits
Angiosperm (plant with flowers) and
insect
Many plants depend
on pollinators for their
reproduction. They
provide nectar to
attract these
pollinators. The
pollinator gets fed and
the plants reproduce!
Bacteria and plants
Bacteria in the nodules of
some plants can take
nitrogen gas from the
atmosphere and turn it
into a form that can be
used by the plant. In
return, the plant protects
the bacteria from harmful
oxygen and the bacteria
get food from the plant.
nodule
Green algae and fungus = lichen
Lichen consist of a
fungus with a
photosynthetic green
algae.
The algae provides
food for both of them
and the fungus
provides a habitat for
the algae.
Commensalism (+,0)
Relationship where one organism benefits and the
other is not affected.
Few examples exist because of the difficulty of
showing that one of the organisms is not affected
by the other.
Cattle and egret
The cattle stir up
grasshoppers and
other insects that the
egret likes to eat.
There are no
apparent benefits to
the cow.
Shark and remora
The remora
benefits by
getting food from
the shark’s meal.
There’s no
apparent benefit
to the shark.
Whale and barnacle
The barnacle larvae
swim around and
attach to the whale,
where the adult
forms. This habitat is
a good one for
providing food. The
whale does not
appear to be harmed.
Parasitism (+,-)
Relationship where one organism benefits and the
other is harmed.
Parasites rarely kill their hosts because to do so
would ultimately harm the parasite!
Wasp and caterpillar
Adult wasps insert their
eggs beneath the skin of
the hornworm larva.
The eggs hatch and the
young feed on
hornworm until they
pupate. Although the
parasite is harmful to
the worm, it is
important in
controlling hornworms
in agriculture.
Mistletoe and tree
Mistletoe lives off
the branches and
stems of other
trees. It can
photosynthesize a
little, but not
enough to meet its
needs. The tree can
be very harmed.
mistletoe
Heartworms and dogs
The worm larvae are transferred from
dog to dog through the bite of an
infected mosquito. The mosquito
sucks larval heartworms with blood
from an infected dog. The mosquito
then bites another dog and transfers
these microscopic larvae as it bites.
During the next few months, these
larvae migrate through dogs bodies
arriving at the heart, where they
become adults.
The crab Lybia tessellata carries a pair of sea
anemones on its claws. The crab uses the sea
anemone’s stinging tentacles as protection and the
sea anemone obtains small food particles released
by the crab as it feeds.
Which type of symbiotic relationship does this
best illustrate?
A. Commensalism
B. Mutualism
C. Parasitism
D. Predation
2. Competition
When two
organisms
attempt to use
the same
space and
resources at
the same time.
These two
flowering plants
are competing
for the same
space which
means both of
them are
harmed.
Competitive Exclusion Principle
No two
species can
occupy the
same niche
in the same
habitat at
the same
time.
Introduced species
• A species that is not native to an
area
• AKA: nonnative, alien, or exotic
species
• Creates problems in ecosystems
because there are no natural
predators to keep the population
size down
• Frequently results in the
competitive exclusion of a native
species
• Ex: kudzu – Introduced to the
US in 1876. It outcompetes other
native plants so they don’t have a
place to grow.
Invasive species
• A species is considered invasive if it causes
damage to an established ecosystem.
• All invasive species are exotic, but not all exotic
species are invasive.
3. Predation
When one organism benefits by killing and
consuming another organism.
predator  hunter
prey  hunted
Spider and insect
In this predator-prey
relationship, the spider is
eating an insect that it has
trapped.
Cheetah and grazing animal
The relationship between predator and prey
populations can greatly affect the population size
of both.
This is especially true when the relationship is
exclusive.
-----Predator/prey simulation-----
• More prey = more
predators
▫ Think: more prey is
more food!
• # of prey always
increases first
• Less prey = less
predators