Transcript Ecological Relationship Notes

EQ: What are the Relationships
between organisms in an ecosystem?
.
Types of ecological interactions
competition
predation
Symbiosis
mutualism
Commensalism
Parasitism
Habitat-area where an organism is best adapted
to finding water, food, and enough space to
live
One habitat might contain hundreds or even
thousands of species.
A rotting log in a forest can be home to many
species of insects, including termites that eat
decaying wood and ants that feed on the
termites.
Other species that live on and under rotting log
include millipedes, centipedes, spiders, and
worms.
Niche– the specialized role a
single organism has in a habitat
Competition – two species share a requirement for a
limited resources  reduces fitness of one or both species
What are limiting Factors?
In the natural world, limiting factors
like the availability of food, water,
shelter and space can change animal
and plant populations.(keeps a
population from growing to large)
Carrying Capacity--Carrying
capacity refers to the
maximum number of
individuals who can be
supported in a given area
within natural resource limits
Competition
• Competition in an interaction between
two organisms that are using the same
limited resource.
• Competition can be within the same
species or between different species
• Ex. Squirrels compete with other
squirrels for nuts, but also compete with
deer and chipmunks for nuts
Predation – one species feeds on another  enhances
fitness of predator but reduces fitness of prey
herbivory is not a form of
Predation
Predator and Prey
An organism’s niche
includes how it avoids
being eaten and how it
finds or captures its food.
Predators are consumers
that capture and eat other
consumers. The prey is the
organism that is captured
by the predator.
Predator and Prey
The deer is
being eaten
by the
python. It is
prey.
The python
has captured
and is eating
the deer.
Predator and Prey
Predator
Prey
Prey Defenses
• Predation usually results in
the evolution of defensive
adaptations in prey.
• These can include:
– Chemical defenses (toxins,
poison, acrid sprays)
– Behavior (living in groups, scouts,
alarm calls)
– Morphological features (spines,
color, structures that allow you to
run fast or detect predators), and
other traits
•
Photo Credit: Rhett A. Butler @ mongabay.com
Caterpillar with Venomous Spines
Predator/Prey Relationship
The presence of predators usually increases the
number of different species that can live in an
ecosystem.
Predators limit the size of prey populations.
As a result, food and other resources(limiting
factors) are less likely to become scarce, and
competition between species is reduced.
Symbiosis-- 3 types
Sym- together
Bio- life/living
Osis- Condition of
Symbiosis
Not all relationships
among organisms involve
food.
Many organisms live
together and share
resources in other ways.
Any close relationship
between species is called
symbiosis. Video LINK
Symbiosis – two species live together  can include
parasitism, mutualism, and commensalism
Mutualism – two species provide resources or
services to each other  enhances fitness of
both species.
Mutualism
• Bees travel from flower
to flower to collect
nectar
– The flowers get
pollinated and the bees
get nectar to make honey
Mutualism
• There is a protozoan in
the gut of a termite that
helps it to digest the
cellulose in the wood
– The protozoan gets its
food delivered and has a
place to live and the
termite has help in
digestion
Commensalism – one species receives a benefit from
another species  enhances fitness of one species; no
effect on fitness of the other species
Commensalism
• Certain species of crab
carry venomous sea
urchins on their backs
– Gives the crab protection
from predators
Parasitism – one species feeds on another  enhances
fitness of parasite but reduces fitness of host
Parasitism
• Leeches attach to their
victims and inject an
anti-coagulant to keep
the blood from clotting
– Leeches get a meal, and
the organism loses blood
and can get open wounds
which can become
infected.