Download Ecology

April 30, 2009
• What are the levels of
organization?
• Where does all energy come
from?
Ecology
What is ecology?
• Ecology is the study of the
interactions of living organisms with
one another and with their physical
environment (soil, water, climate…)
• ECO = house
• LOGY = the study of
Biosphere
• The biosphere contains the
combined portions of the
planet in which all of life
exists, including land, water
and atmosphere.
• Ecologists ask questions
about events and organisms
that are in the biosphere to
understand the relationships
within the biosphere.
SPECIES
• A group of organisms so
similar to one another
that they can breed and
produce fertile offspring
POPULATION
• A group of individuals
that belong to the same
species and live in the
same area
COMMUNITY
• An assemblage of
different populations that
live together in a defined
area
ECOSYSTEM
• A collection of all the
organisms that live in a
particular place, together
with their physical
environment
BIOME
• A group of ecosystems
that have the same
climate and dominant
communities
LEVELS OF ORGANIZATION
Species
Population
Community
Ecosystem
Biome
Biosphere
What is the highest level
of organization?
The entire biosphere
ECOLOGICAL METHODS
Three basic approaches to conduct
ecological research:
–Observing
–Experimenting
–Modeling
ECOLOGICAL METHODS
Why might an ecologist set up
an artificial environment in a
laboratory?
To imitate and manipulate
conditions that organisms may
encounter in the natural world.
ECOLOGICAL METHODS
Many ecological phenomena are
difficult to study because they
may occur over very long periods
of time, or they occur on such
large spatial scales (and are too
big to study)…
ECOLOGICAL METHODS
Scientists make models to
gain an insight into complex
phenomena
ENERGY FLOW
• Every organism needs…
…ENERGY!!!
ENERGY FLOW
• What are autotrophs?
• Organisms that capture
energy from the sun or
chemicals to produce their
own food.
ENERGY FLOW
• What is a producer?
• Organisms that first
capture energy
(Autotrophs)
• FIRST TROPHIC LEVEL
ENERGY FLOW
• During photosynthesis,
autotrophs use light energy
to power chemical reactions
that convert CO2 and water
into oxygen and high energy
sugars (glucose).
PRODUCERS
LAND:
Plants
UPPER LAYERS OF OCEAN:
Algae
TIDAL FLATS/SALT MARSHES:
Photosynthetic
bacteria / cyanobacteria
CHEMOSYNTHESIS
• Chemosynthesis is the
process by which organisms
use CHEMICAL energy to
PRODUCE carbohydrates.
• Making food without sunlight!
CHEMOSYNTHESIS
• What organisms carry out
chemosynthesis?
• BACTERIA
• Where do they live?
CHEMOSYNTHESIS
• Where do these
bacteria live?
• Remote places—
volcanic vents on deep
ocean floor, hot springs
in Yellowstone Park
CHEMOSYNTHESIS
• Where do these
bacteria live?
• Common places—
tidal marshes along
the coast
ENERGY FLOW
• If AUTOTROPHS are called
PRODUCERS, because
they make their own food,
what are HETEROTROPHS
called?
CONSUMERS
• Organisms that consume plants or
other organisms to obtain energy.
• All organisms that are NOT
producers!!! (Heterotrophs)
• Three categories
– Primary
– Secondary
– Tertiary
PRIMARY CONSUMERS
• Herbivores
–Eat plants or other primary producers
• Examples
– Cows
– Horses
– Rabbits
– Some Insects
• SECOND TROPHIC LEVEL
SECONDARY CONSUMERS
• Carnivores
–Animals that eat animals
–Examples: tigers, wolves, snakes
• Omnivores
–Animals that are herbivores and
carnivores
–Examples: bears, humans
• THIRD TROPHIC LEVEL
TERTIARY CONSUMERS
• Carnivores that consume other
carnivores
• Known as “top carnivores”
• Example:
–A hawk that eats a snake
–A lion that eats a hyena
• FOURTH TROPHIC LEVEL
DETRITOVORES
• Feed on plant and animal
remains and other dead
matter
• Examples: mites,
earthworms, snails, crabs
DECOMPOSERS
• Break down and absorb nutrients
from dead organisms
• They cause decay
• Decomposition of bodies and
wastes releases nutrients back into
the environment to be recycled by
other organisms.
• Examples: bacteria, fungi
SCAVENGERS
• Do not kill their food—they
search for a source of food that
is already dead
• “Clean-up” the ecosystem
• Examples: buzzards
FEEDING RELATIONSHIPS
• Energy flows through an
ecosystem in ONE direction:
Sun (or inorganic chemicals)
Autotrophs/Producers
Heterotrophs/Consumers
FOOD CHAIN
• A food chain is a series of
steps in which organisms
transfer energy by eating or
being eaten.
• It is how energy moves
through an ecosystem!
FOOD WEB
• A food web is a network of
complex interactions formed
by the feeding relationships
among the various organisms
in an ecosystem.
FOOD CHAIN vs. FOOD WEB
• A food web will link
together all of the food
chains in a particular
ecosystem…
A
terrestrial
food
chain
A
marine
food
chain
TROPHIC LEVELS
• A trophic level is a step in a food
chain or food web.
• Different organisms are on
different levels depending on their
source of energy.
• Where does energy come from?
SUN
TROPHIC LEVELS
1st TROPHIC LEVEL
Producers
2nd TROPHIC LEVEL Primary
Consumers
3rd TROPHIC LEVEL Secondary
Consumers
4th TROPHIC LEVEL Tertiary
Consumers
TROPHIC LEVELS
• A consumer in a food chain
depends on the trophic
level below it for energy.
ECOLOGICAL PYRAMIDS
• An ecological pyramid is a
diagram that show the
relative amounts of energy
or matter contained within
each trophic level of a food
chain or food web.
ECOLOGICAL PYRAMIDS
• Only part of the energy
stored in a trophic level is
passed on to the next
because organisms use
much of the energy they
con
ENERGY PYRAMID
• All energy originates from the
sun (or inorganic chemicals).
• Sunlight (radiant energy) is
converted to digestible energy
by plants during
photosynthesis.
ENERGY PYRAMID
• When the plants are eaten, the
energy is transferred to animals
to sustain life.
• Energy is transferred up the
food chain.
Tertiary
Consumers
Secondary Consumers
Primary Consumers
Producers
THE RULE OF TENS
• Only 10% of the energy in a
trophic level is passed on to the
next level…90% of the energy is
lost—where does it go?
• Given off as HEAT!!
BIOMASS PYRAMID
• Biomass is the total amount
of living tissue within a
trophic level.
• Represents the amount of
potential food available at
each trophic level.
PYRAMID OF NUMBERS
• Shows relative number of
individual organisms at each
trophic level.
LIMITATIONS OF
TROPHIC LEVELS
Why can there not be
too many links to one
food chain?
• Each trophic level can
support about one-tenth the
amount of living tissue as
the level below it, because
only 10% of the energy is
passed up!!!
A few more things…
HABITAT
• The area where an
organism lives
• Includes both biotic
and abiotic factors
Biotic vs. Abiotic
Biotic
• Bio- means: life
• Tic- means:
pertaining to
Biotic factors are the
living organisms in a
habitat!
Abiotic
• Bio- means: life
• Tic- means:
pertaining to
• A- means: no, not
Abiotic factors are all
the physical aspect of
a habitat!
Examples: soil, water,
weather
Abiotic Factors
•Water
•Air
•Soil
•Heat
•Light