Download CP Ecology Notes Part 8

Community
• COMMUNITY: interactions between the
LIVING organisms in the ecosystem
NICHE
NICHE
• The role of an organism in its environment.
– Type of food it eats
– Where it gets it’s food
– Its reproduction cycle
– What temperatures it can withstand
• Two species cannot occupy the same
niche.
Predator-Prey
Interspecific
• Between
• Example:
• Chipmunks and squirrels competing for
pine nuts.
• Spruce, Pine, Fir trees competing for
space, nutrients, and sunlight
Intraspecific
• Within
• Example:
• Coral larvae settle to establish new
colonies are competing for space with
other coral larvae of the same species
Which type of competition is most
challenging for organisms?
Which type of competition is most
challenging for organisms?
• Intraspecific
• Niches and habitats same or more similar
than between species
Mutualism
• Crocodiles try to eat most birds that come near them. But one kind of bird
can walk about among crocodiles and be quite safe. In fact, these birds even
lay their eggs in the same place where the crocodiles lay their eggs! The
birds are called water dikkops and they eat insects that bother the
crocodiles. Of course, this gives the birds an easy meal, but it also makes
the crocodiles more comfortable. So the birds are really helping the
crocodiles and maybe that’s why the crocodiles don’t harm them.
• What aphids have that ants want is something
called honeydew, a sweet substance that is
excreted by aphids through their anus and
contains surplus sugar from the aphid's diet.
Ants protect aphid eggs during the winter , and
carry the newly hatched aphids to new host
plants, where the aphids feed on the leaves and
the ants get a supply of honeydew.
• For the bees, the pollen and nectar from many flowers is
an important source of fats, proteins, vitamins, and
minerals. The nectar is a source of energy. Bees
gradually switched from eating other insects to flowers
as their source of food. With the passage of time, bees
have become completely dependent on flowers as a
food source.
• As bees travel from one blossom to another, pollen
clings to their fuzzy bodies. It is then transferred to the
other flowers of the same species. This pollinates or
fertilizes the plant. Plants then can produce their own
fruits and seeds.
commensalism
• Pseudoscorpions hitching ride on a fly’s leg, Costa Rica.
Pseudoscorpions, tiny relatives of true scorpions, often
engage in the practice of phoresy, or hitchhiking.
Ecologists still debate whether pseudoscorpions
sometimes harm the organisms that carry them around,
but many believe that the pseudoscorpions gain a ride
without any real cost to their carriers. If so, this is a good
example of a commensalism, a relationship in which one
partner benefits and the other neither benefits nor is hurt.
Pseudoscorpions are quite small (typically about 1/10 of
an inch or 3 mm long) but are impressive predators.
Although they do not have the stinger of a true scorpion,
they have poison glands in their pincers and feed heavily
on tiny arthropods such as mites and springtails.