Download Ecology (NEW 2008)

What is Ecology?
The study of organisms
and their interactions
with the environment.
What is a Population?
A group of organisms of the
SAME species living in one place.
What is a Community?
All of the interacting organisms
living in an area.
(Many populations living together.)
Biotic vs. Abiotic Factors
 Biotic Factor:
Living parts of the
environment.
 Abiotic Factor:
Nonliving parts of the
environment.
What is an ecosystem?
All of the ORGANISMS and the ABIOTIC FACTORS
found in a particular place.
What is the Biosphere?
ALL parts of the Earth that support life.
Energy Transfer in an
Ecosystem
What are Autotrophs?
 Organisms that make their own food!
 Plants
 Producers
What are Heterotrophs?
Consumers
Can’t make their own food
4 Types of Consumers
Herbivores
 Eat Producers!
 Primary (1º) Consumers
Carnivores
 Eat other consumers!
 Secondary (2˚)/Tertiary (3º) Consumers
Omnivores
 Eat both producers and consumers!
Detritivores
 Consumers that feed on the “garbage” of an
ecosystem, such as organisms that have recently
died, fallen leaves and branches, and animal
wastes.
 Scavenger: Vulture
 Ex: Bacteria/Fungi  Decomposers: cause decay
by breaking down.
Energy Flow in an Ecosystem
Trophic Levels indicate an organism’s
position in the sequence of energy transfers.
(layer in the structure of feeding relationships)
Biomass: total mass of organic matter at each trophic level
Energy Flow in an Ecosystem
10% Law: Only 10% of the total stored
energy in one trophic level is transferred
to the next trophic level.
Food Chain
A single pathway of feeding relationships among
organisms in an ecosystem that results in
energy transfer.
Food Web
(network of food chains)
Food Webs
Food Webs
A certain ecosystem contains the following
organisms:
Grass
Grasshoppers that eat grass
Sparrows that eat grass and grasshoppers
Frogs that eat grasshoppers
Snakes that eat frogs and sparrows
Foxes that eat snakes
Hawks that eat snakes
Mushrooms
Create a food web showing the flow of energy
from one organism to another.
Pond Food Web
A pond ecosystem contains the following organisms:
Algae
Flies that eat algae
Birds that eat fish, grasshoppers, snakes, mice
Otters that eat fish
Fish that eat algae, flies,crayfish, frogs, and grasshoppers
Grass
Snakes that eat frogs and mice
Grasshoppers and mice that eat grass
Crayfish that eat algae
Frogs that eat flies
Create a food web showing the flow of energy from one
organism to another.
What is a Niche?
 An organism’s role in its environment
Includes
Range of conditions the species
can tolerate
How the species obtains
resources
Reproduction Time
Fundamental vs. Realized Niche
A. Fundamental: An organism’s full
potential range of physical, chemical,
biological conditions and resources it
could theoretically use if there was no
competition from other species.
B. Realized: Range of resources it
actually uses.
A species’ fundamental niche
is ALWAYS as large or larger
than its realized niche.
Community Ecology
Ecosystem Relationships
Competition
Results from fundamental niche overlap
Competitive Exclusion Principle
G.F. Gause (1934)
If two species, with the same niche, coexist in the
same ecosystem, then one will be excluded from the
community due to intense competition.
Competitive Exclusion Principle
Explain how two similar species
of birds are able to inhabit the
same area and even nest in the
same tree without occupying
the same niche.
The birds’ behavior is an example of resource partitioning.
One species may feed on insects, and the other may feed
on seeds. They may nest on different levels of the tree.
At least one factor in the birds’ niches must differ to
allow them to exist closely together.
Generalist vs. Specialist
A.



Generalist: Occupies a broad niche
Can live in many places
Eats a variety of foods
Tolerate a wide range of environmental
conditions
B.



Specialist: Narrow niche
Only eat one type of food
Lives in only one habitat
Tolerate a narrow range of climate
Community Ecology
Ecosystem Relationships
 Symbiosis: Organisms of different species
living in close association with one another.
1. Mutualism: Cooperative relationship
 Both organisms benefit
Examples
Lichen
Pollination
Community Ecology
Ecosystem Relationships
 Clown Fish and Sea Anemones
The clown fish is able to produce a special mucus that
causes the anemone not to release its stings. It is also
believed that the movements of the fish inform the
anemone of its identity. In return for the anemone's
protection, the fish brings scraps to it, and lures larger
fish into the anemone's tentacles.
Community Ecology
Ecosystem Relationships
 Commensalism: One species benefits and
the other is not affected
Examples
Whales/Barnacles
Orchids/Trees
Juvenile Fish/Jellyfish
Community Ecology
Ecosystem Relationships
3. Parasitism: One individual is harmed while the other
individual benefits
Examples
Tapeworms
Fleas, Ticks, Lice
Community Ecology
Ecosystem Relationships
Parasites can be grouped into two general categories:
1. Ectoparasites
(ticks, fleas, lice, leeches, lampreys, mosquitoes)
2. Endoparasites
(diseasing causing bacteria, malaria parasite, tapeworms)
Community Ecology
Ecosystem Relationships
Predation
Natural selection favors
adaptations that improve the
efficiency of predators at
finding, capturing, and
consuming prey.
Biological Magnification
Increasing Concentration of a harmful
substance in organisms at higher trophic
levels in a food chain or food web.
Example: DDT (a pesticide)
Affects the entire food web, although top
carnivores are at highest risk
In 1962, Rachel Carson (a biologist)
wrote a book called Silent Spring that
alerted people to the dangers of
biological magnification.
Biological Magnification