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Ecology
What is Ecology?
• Study of interactions
among
1. Organisms (LivingLiving)
2. Organisms and
their environment
(Living-Nonliving)
Species- a group of similar
organisms that can breed and
produce fertile offspring.
3-2 Ecological Levels of Organization
Section 3-1
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Section:
Levels of Organization
• Individual- one
organism (living)
• Ex a moose
Levels of Organization
• Population- groups
of individuals that
belong to the same
species and live in the
same area. (livingliving same species)
• Ex many moose
Levels of Organization
• Community- groups
of different populations
(more than one
population or different
groups of species)
Ex: many groups of
moose, beavers, trees,
grass (all living)
Levels of Organization
• Ecosystem- all
organisms in a
particular area along
with the nonliving.
(living and nonliving)
Ex: many groups of
moose, beavers,
trees, grass, rocks,
water, mountains
Levels of Organization
• Biome- group of
ecosystems that have
the same climate and
similar dominant
communities
• Biomes: tropical rain forest,
tropical dry forest, tropical
savannah, temperate
grassland, desert, temperate
woodland and shrub land,
temperate forest,
northwestern coniferous
forest, boreal forest (taiga),
tundra, mountains and ice
caps
Levels of Organization
• Biosphere- all of the
planet where life
exists, includes land,
water, and, air
• Life extends 8 km up
and 11 km below the
surface
What shapes an ecosystem?
• Biotic factors-
• Abiotic factors-
• Ex. Interactions
• Ex. Temperature,
biological (living)
influences on
ecosystem
between organisms,
predation, symbiosis,
etc.
nonliving influences
on ecosystems
precipitation, nutrient
availability, soil type,
sunlight.
What are the roles of organisms in
an ecosystem?
• Habitat- an area where an organism lives
• Niche- full range of physical and biological
conditions in which an organism lives and the way
in which the organism uses those conditions.
– Includes where in the food chain it is, and where an
organism feeds
• Habitat is like an address in an ecosystem and a
niche is like the job in an ecosystem.
In an ecosystem, organisms
need to be able to obtain
energy.
• Producers- make their own food
• Consumers- get energy from consuming
producers
Producers
• Capture energy from
•
sunlight or chemicals
and use the energy to
produce food.
Producers are
autotrophs- they
make food from their
environment
Autotrophs convert food to
energy in 2 ways:
• Get energy from the sun by photosynthesis
• Get energy without light by chemosynthesis
Consumers
• Consumers are heterotrophs- get energy from
other organisms
• Types of Consumers:
–
–
–
–
Herbivores- eat only plants
Carnivores- eat animals
Omnivores- eat both plants and animals
Detritivores (decomposers)- eat dead matter
(plants and animals)
Feeding Relationships
• Energy flows through an ecosystem in one direction
from:
–
–
–
–
1. the sun or inorganic compounds
2. To autotrophs (producers)
3. To heterotrophs (consumers)
Decomposers get energy from decomposing dead
organisms
Food Chain- a series of steps in which organisms
transfer energy by eating or being eaten.
Food Web- A network of
feeding relationships.
(More realistic that a food
chain)
Trophic levels
• Each step in a food
chain or a food web is
called a trophic level.
– Producers are the first
trophic level
– Consumers are the
second, third, or
higher trophic level
• Each trophic level
depends on the one
below for energy
• Only part of
the energy
stored in one
level can be
passed to the
next
• Most energy
is consumed
for life
processes
(respiration,
movement,
etc., and heat
is given off)
Flow of Energy
Energy Pyramid (cont’d)
• Only 10% of the
energy available
within one trophic
level is transferred to
organisms in the next
trophic level
• Less than 1% is
actually used by
organisms on Earth
Biomass Pyramid
• Biomass- the total amount of living tissue
within a given trophic level.
• A biomass pyramid represents the amount of
potential food available for each trophic
level in an ecosystem.
Biomass Pyramid
50 grams of
lion tissue
500 grams of
giraffe
5000 grams of
greenery
Pyramid of Numbers
• Ecological pyramids can also be based on the numbers
of individual organisms at each trophic level.
• The pyramid of numbers shows the relative number of
individual organisms at each trophic level.
• Because each trophic level harvests only about 1/10th of
the energy from the level below, it can support only
about 1/10th the amount of living tissue.