Transcript 3. Community Interactions New-network

Community Interactions
Remember…it’s the
INTERACTIONS that are important
in ecology!
Compare and Contrast
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Species
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Population
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Community
Definitions
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Species: A class of individuals having common
characteristics (ex. Mankind, cats etc.)
Population: the number of individuals that occupy a
certain area. (ex. People in Wilmington)
Community: Different species interacting together in
a certain environment (ex. Plants, squirrels, and fox)
Competition
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Same or different species attempt to
use an ecological resource in the
same place at the same time
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resource = necessity of life (water,
nutrients, light, food, space)
Community Interactions
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No two species can occupy
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the same niche
in the same habitat
at the same time
Direct competition in nature often
results in winner and loser – losing
organism fails to survive
Food Chain
A
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food chain is a food pathway that
links different species in a community.
 In a food chain, energy and nutrients
are passed from one organism to
another.
A series of steps in which organisms
transfer energy by eating and being
eaten.
 i.e. Wheat  mouse  snake  hawk
Food Chain Example
 Food
Chains rarely contain more
than six species because
amount of energy passed on
diminishes at each stage, or
trophic level.
 The
longest chains usually
involve aquatic animals.
 In
a food chain, an animal
passes on only about 10 percent
of the energy it receives. The
rest is used up in maintaining it's
body, or in movement, or it
escapes as heat.
Food Chain
Food Web
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A community of living things may
contain hundreds or even
thousands of different species.
Each species is usually involved in
several different food chains.
Different food chains often
interconnect to form a large
network, called a food web.
Food Web
Trophic Levels
A trophic level of an organism is the
position it holds in a food chain.
1. Trophic level 1are primary producers
or autotrophs
2. Trophic level 2 is herbivores
(organisms that eat primary
producers) - organisms at this level are
also called primary consumers.
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3. Trophic level 3 is predators that eat
herbivores - organisms at this level
are also called secondary
consumers.
4. Trophic level 4 is predators that eat
secondary consumers. Tertiary
consumers
5. Trophic level 5 is predators that eat
secondary consumers/tertiary
consumers
Decomposers (such as bacteria) start
the cycle again.
Trophic Levels
Each step in a food chain or food web
 1st level = producers
 2nd, 3rd, or higher levels = consumers
 Usually no more than 5 levels because
90% of energy is lost at each level.
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PREDATOR
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An animal that hunts and kills animals
for food
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The term predator usually refers to
animals that catch and kill.
They have special adaptations to help
them find and catch their food. These
include good vision, a keen sense of
smell, or strong legs for rapid movement.
PREY
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Prey are animals that are lower on the
food chain that are eaten by predators.
Prey also have special adaptations to
help them survive the attack of their
predators. Camouflage helps them
blend in, sharp senses warn them of
attack, and speed allows them to
escape.
Write if the organism is a producer, consumer
or decomposer. Tell what trophic level they
are at as well.
Organism
Type
Trophic Level
Human
Deer
Pine Tree
Bear
Rabbit
Bacteria
Organism
Mouse
Snake
Wheat
Maggot
Bluegrass
Hawk
Type
Trophic
Level
Organism
Millipede
Trout
Sparrow
Cat
Frog
Algae
Type
Trophic
Level
Draw a Food Chain
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Draw a food chain with the organisms
you worked with above. Try to make
your food chain with at least 5
organisms.
If you want to you can also work with
other animals you can think of to make
your food chain
Example of a Food Chain
Biotic
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Are living things in an environment that
interact with non-living.
What are some biotic things that could
be an environment?
Plants and animals
Why are these important to have an
environment?
Abiotic
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Are the non-living factors in an
environment.
What are some non-living things that
should be in an environment?
Temperature, rocks and minerals,
water
How could these factors affect the
environment?
Biological Interactions
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Symbiosis-is a close ecological relationship
between the individuals of two (or more)
different species.
Sometimes a symbiotic relationship benefits
both species, sometimes one species
benefits at the other's expense, and in other
cases neither species benefits.
Biological interaction types
Mutualism
-- both species benefit
• Commensalism
-- one species benefits, the other is
unaffected
• Parasitism
-- one species benefits, the other is
harmed
•
Aquatic
Food
Web
Energy & Matter
in an Ecosystem
Other Community Interactions
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Predation
Symbiosis
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Parasitism
Mutualism
Commensalism
Predation
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One organism captures and feeds on
another organism
 Predator – the one killing and
eating
 Prey – the food
herbivory is a form of
predation
Symbiosis
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When two species live close together.
Three types:
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Parasitism – one is harmed (host), one
benefits (parasite)
Mutualism – both benefit
Commensalism – one is neutral, one benefits
Parasitism
Mutualism
Commensalism
Mutualism
Parasitism
Commensalism