Transcript Community Relationships

Community Relationships
Ecology & Levels of Organization
• Ecology
– Is the scientific study of the interactions between organisms and
the environment
• Organisms and their interactions with one another and the
environment have led scientists to organize nature into
different levels as follows:
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Organism
Population
Community
Biome
Ecosystem
Biosphere
Organism - an individual animal, plant, or single-celled life form
An organism’s job in a community is called its niche.
Organism
Population - the collection of organisms of a particular species, living in a given
geographic area or space
Population
Community - various collections of organisms sharing an environment
Community
Biome - is a major regional group of distinctive communities best adapted to the
region's physical natural environment, latitude, elevation, and terrain.
(ex: savanna, steppe, prairie)
Biome
Ecosystem - the collection of biotic (living) and abiotic (nonliving) components and
processes in one particular area of the biosphere
Ecosystem
Biosphere - the outermost part of the planet's shell — including air, land and
water — within which life occurs
Biosphere
Habitat vs. Niche
• Different Species have different niches.
• A niche is the organism’s “Job”:
– What does it contribute to the community?
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It can absorb sunlight to produce food for others.
It can be preyed upon by others.
It can be parasitized by others.
It can go to the bathroom and fertilize the ground.
It can die and its body will go back to the earth.
• Niche is different than habitat, because habitat
describes the conditions in which the organism
lives. A niche describes the organism’s purpose.
• Niche is often described by an organism’s
relationship with other organisms in the
community.
Organisms Can Have Symbiotic
Relationships
– Symbiosis – a relationship where two species live
closely together
• Mutualism
– Symbiotic relationship in which both species benefit from the
relationship
Ant-aphid mutualism: the aphids are protected against predators by the ants who cultivate the
aphids for their secretions of honeydew, a food source.
The Roridula gorgonias plant is sticky and captures bugs, but does not eat the bugs. This bug
eats the captured bugs and its feces fertilizes the soil and feeds the plant.
Students Should Be Able to Identify and
Describe Symbiotic Relationships
– Symbiosis – a relationship where two species live
closely together
• Mutualism
– Symbiotic relationship in which both species benefit from the
relationship
• Commensalism
– Symbiotic relationship in which one organism benefits and the
other organism is neither helped nor harmed
A small copepod crustacean (note paired egg sacs) on Phyllidia
The commensal shrimp Periclimenes imperator on Chromodoris tinctoria
Students should be able to identify and
describe symbiotic relationships
– Symbiosis – a relationship where two species live
closely together
• Mutualism
– Symbiotic relationship in which both species benefit from the
relationship
• Commensalism
– Symbiotic relationship in which one organism benefits and the
other organism is neither helped nor harmed
• Parasitism
– Symbiotic relationship in which one organism lives in or on
another organism (the host) and consequently harms it
Mites parasitising a harvestman.
This plant is a Holoparasite; a plant that is completely parasitic on other plants and has
virtually no chlorophyll.
Organisms can have Predator/Prey
relationships
• Many predators specialize in hunting only one species
of prey.
– The specialists are usually particularly well suited to capturing
their preferred prey.
– The prey in turn, are often equally suited to escape that
predator.
– This tends to keep the populations of both species in
equilibrium.
• Other predators are more opportunistic and will kill
and eat almost anything.
Specialist Predator
Specialist Predator
Opportunistic Predator
Opportunistic Predator
Prey/Predators Continued
• When hunger is not an issue, most predators
will generally not seek to attack prey because
it costs them too much energy.
– (This is why sharks in an aquarium will not attack
the fish in the tank)
Prey/Predators Continued
• Predators at the top of the food chain (such as
large sharks, crocodiles, and humans) are
called the apex predators and can often
greatly affect the food chain beneath them.
– Species that have a strong influence on the food
chain are called keystone species.
The Clean Up Crew
• And of course, you have to have organisms
that return dead organisms back to the eart:
– Scavengers eat freshly dead material, like
opossums and buzzards.
– Detritivores eat detritus (decaying matter), like
maggots.
– Decomposers complete the conversion of organic
material to the earth; like bacteria and
fungus(mold).
The Food Chain
Energy Comes to
Earth
Energy is
Absorbed
by Plants
Primary
Consumer
Producer
Secondary
Consumer
Tertiary
Consumer
Quaternary
Consumer
Tertiary Consumer
Secondary
Consumer
Primary
Consumer
Producer
Decomposers
Energy Pyramid