What is
Ecology?
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What is Ecology??
• The study of interactions that
take place between organisms
and their environment.
• It explains how living
organisms affect each other
and the world they live in.
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A Key Theme in Ecology
• No single organism is isolated!!
– The interconnectedness or
interdependence of all organisms is central
to the study of ecology
– The survival of organisms depends on their
interactions with their surrounding
environment
• Ex: Humans cannot live without the plants that
produce food and oxygen
The Nonliving Environment
• Abiotic factors- the
nonliving parts of an
organism’s environment.
• Examples include air
currents, temperature,
moisture, light, and soil.
• Abiotic factors affect an
organism’s life.
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The Living Environment
• Biotic factors- all the
living organisms that
inhabit an environment.
• All organisms depend on
others directly or
indirectly for food,
shelter, reproduction, or
protection.
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Abiotic or Biotic?
Biotic
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Abiotic or Biotic?
Abiotic
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Abiotic or Biotic?
Abiotic
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Abiotic or Biotic?
Biotic
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Levels of
Organization
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What are the Simplest Levels?
• Atom
• Molecule
• Organelle
• Cell
• Tissue
• Organ
• OrganSystem
• Organism
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Levels of Organization
• Ecologists have organized the
interactions an organism takes
part in into different levels
according to complexity.
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1st Level of Organization
• Organism:
An individual
living thing that
is made of cells,
uses energy,
reproduces,
responds, grows,
and develops
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2nd Level of Organization
• Population:
A group of
organisms, all
of the same
species, which
interbreed and
live in the
same place at
the same time.
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3rd Level of Organization
• Biological
Community:
All the
populations of
different
species that
live in the same
place at the
same time.
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4th Level of Organization
• Ecosystem:
Populations of plants
and animals that
interact with each
other in a given
area with the
abiotic components
of that area.
(terrestrial or
aquatic)
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5th Level of Organization
• Biosphere:
The portion of
Earth that
supports life.
• The highest level
of organization
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The Biosphere
• Life is found in air, on
land, and in fresh and salt
water.
• The BIOSPHERE is the
portion of Earth that
supports living things.
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What level of organization?
Organism
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What level of Organization?
Community
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What level of Organization?
Population
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Organization of Ecology
Draw the diagram of hierarchical
organization of ecology from P.361
Habitat vs. Niche
Niche - the role a species plays in
a community; its total way of life
Habitat- the place in which an
organism lives out its life
Habitat vs. Niche
A niche is determined by the
tolerance limitations of an
organism, or a limiting factor.
Limiting factor- any biotic or
abiotic factor that restricts the
existence of organisms in a
specific environment.
Habitat vs. Niche
Examples of limiting factors •Amount of water
•Amount of food
•Temperature
•Amount of space
•Availability of mates
Niche Differences
• Generalists are species with broad niches
– Can tolerate a range of conditions and use a
variety of resources
• Ex: Virginia opossum  found all over the US and
can eat a wide range of food
• Specialists are species that have narrow
niches
– Ex: koalas  only feed on leaves from a few
species of eucalyptus trees
Organisms in a Changing Environment
Tolerance Curve: A graph of
performance versus values of an
environmental Variable
Tolerance Curve for
Cutthroat Trout –
Shows they can
tolerate temps
between 5 and 23°C)
Acclimation
• Acclimation is the process by which
organisms can adjust their tolerance
to abiotic factors
– Ex: Going to the mountains
• If you spend a few weeks in the mountains,
your body will acclimate to the lower oxygen
levels by producing more red blood cells in your
body
• This will allow your blood to carry more oxygen
– Acclimation IS NOT adaptation!!
• Adaptation is a genetic change in a species that
occurs over many generations – acclimation
occurs within the lifetime of a species
Acclimation
Question: If you raised the
temperature of a goldfish bowl a
degree every week, and your fish
was able to tolerate higher
temperatures than other
goldfish…Is this Acclimation?
How do organisms deal with change in
their physical environment?
• Strategy 1 – Conformers
• These organisms do not control their internal
conditions and change as their external
environment changes
• example: reptiles are cold blooded
• Strategy 2 – Regulators
• These organisms do control their internal
conditions and maintain within their optimum
range in spite of external conditions
• ex. Mammals maintain constant body temp
What if conditions change too drastically,
How does an organism survive?
• Some species become dormant (a state
of reduced activity) when the
environmental conditions aren't suitable
(like too cold, not enough food, too dry)
• Some species migrate (move to a more
favorable habitat) when conditions
become unbearable
Ch. 18-3 (Ecology)
ENERGY TRANSFER
Nutritional Relationships:
A. Autotrophs: can synthesize (or make)
their own food Ex.) Plants
B. Heterotrophs: can NOT synthesize
their own food and are dependent on
other organisms for their food
Feeding Relationships
Producer- all autotrophs
(plants), they trap
energy from the sun
• Bottom of the food
chain
Feeding Relationships
Consumer- all heterotrophs: they
ingest food containing the sun’s
energy
Herbivores
Carnivores
Omnivores
Decomposers
Feeding Relationships
CONSUMERS
1.Primary consumers
• Eat plants
• Herbivores
• Secondary, tertiary
consumers
• Prey animals
• Carnivores
TYPES OF CONSUMERS
Consumers can be grouped according
to the type of food they eat.
TYPES OF CONSUMERS
Herbivores- Eat Producers
Carnivores- Eat other Consumers
Omnivores- Eat both Producers and
Consumers
Other Consumers
Detritivors:
AKA Scavengers
– Feed on carrion, dead
animals
Decomposers
– Breakdown the
complex compounds of
dead and decaying
plants and animals into
simpler molecules that
can be absorbed
Trophic Levels
• Each link in a food chain is known as
a trophic level.
• Trophic levels represent a feeding
step in the transfer of energy and
matter in an ecosystem.
Trophic Levels
Biomass- the amount of organic matter
comprising a group of organisms in a
habitat.
• As you move up a food chain, both
available energy and biomass decrease.
E
N
E
R
G
Y
Trophic Levels
Tertiary
consumers- top
carnivores
Secondary consumerssmall carnivores
Primary consumers- Herbivores
Producers- Autotrophs
Energy Transfer
• On Average,
10% of Total
Energy is
transferred from
one energy level
to the next.
Trophic Levels
Food chain- simple model that
shows how matter and energy
move through an ecosystem
A Food Chain
Plant
Frog
Insects
Bear
Fish
People
Trophic Levels
Food web- shows all possible
feeding relationships in a
community at each trophic level
• Represents a network of
interconnected food chains
Food chain
(just 1 path of energy)
Food web
(all possible energy paths)