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Chapter 3 Ecology
• Ecology is the study of interactions among
organisms and between organisms and their
environment
Some of the levels at which life can be
• cells
studied include:
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•
•
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organisms
populations
communities
ecosystems
biomes
biosphere
Population
Individual
Biosphere
Biome
Ecosystem
Community
• Cells are the smallest functional unit of life
Nerve cell
• Cells make up organisms.
– Individual living things
Species - individuals that can breed with
one another and produce fertile offspring
Population - all the individuals of the same
species in an area
A population is
always composed
of same-species
organisms
Community - all the populations that live
together in an area
Hawk, snake, bison, prairie dog, grass
• Community and its nonliving surroundings are
called an ecosystem.
– Biotic factors: living things
– Abiotic factors: nonliving things
Hawk, snake, bison, prairie dog, grass, stream, rocks, air
• A biome is a group of ecosystems that
have the same climate and similar
communities.
Tropical forest
Savanna
Desert
Chaparral
Temperate
grassland
Temperate
broadleaf forest
Northern
coniferous forest
Tundra
High mountains
Polar ice
Biosphere - the part of the earth that supports
life
1. A group of animals that live in the same area and can interbreed is called
population
a (n) _____________________
2. The study of organisms and their interactions with the environment is
ecology
known as ___________________________
3. A large area that has a particular climate and distinct plants and animals is
biome
called a ____________________________
4. All of the different populations living in an area (plants, rabbits, coyotes...)
community
is called the _________________________
non-living (abiotic) factors in
5. An ecosystem includes all the living (biotic) and ___________
an area.
biosphere
6. The portion of the planet that can sustain life is the ________
species
7. Animals that can interbreed are called a(n) _______________
3-2 Energy
Flow
consumers
producers
decomposers
nutrients
ENTER FOOD CHAIN
= made available
to producers
abiotic
reservoir
geologic
processes
return to
abiotic
reservoir
Energy flows through ecosystems
The Earth is not a closed system: It needs a constant
input of energy
sun
secondary
consumers
(carnivores)
primary consumers
(herbivores)
producers (plants)
loss of
energy
loss of
energy
• Sun light
– Sun light is the primary
source of energy for our
biosphere.
• Autotrophs/prod
ucers
– Use energy from the
environment to produce
their own food
• Photosynthesis
– Use light
– Plants, mosses, Algae
• Chemosynthesis
– Use chemicals
– Bacteria
Heterotrophs/Consumers: cannot make their
own food. They must eat to get energy
Carnivores
Herbivores
eat only meat
eat only plants
Omnivores
eat both plants and meat
Decomposers/Detritivores
Breakdown plants and animals
Level 4
Tertiary consumer
Food chains
• Trophic levels
– energy from the sun
by producers
•
1st
Sun
top carnivore
Level 3
captured Secondary consumer
level of all food chains
carnivore
Level 2
Primary consumer
– consumers make up the
second, third, or higher levels
– all levels connect to
Level 1
Producer
decomposers
heterotrophs
herbivore
autotrophs
Decomposers
Bacteria
Fungi
Feeding Relationships
A food chain is a series of steps in which organisms transfer
energy by eating and being eaten.
• Arrows follow energy flow
• All energy originates from the sun.
Sun
Bacteria
Inefficiency of energy transfer
• Loss of energy between levels of food chain
– To where is the energy lost? The cost of living!
10%
growth
only this energy
moves on to the
next level in
the food chain
energy lost to
daily living
40%
cellular
respiration
50%
waste (feces)
sun
Ecological Pyramids
•
An ecological pyramid is a diagram that shows the relative amounts of energy or
matter contained within each trophic level in a food chain or food web.
Energy pyramid
Biomass pyramid
Pyramid of Numbers
Shows the relative amount of
energy available at each
trophic level.
Represents the amount of
living organic matter at each
trophic level.
Shows the relative number of
individual organisms at each
trophic level
Ecological pyramid
• Loss of energy between levels of food chain
– can feed fewer animals in each level
sun
Food webs
• Food chains are linked
together into food
webs
• Who eats whom?
– a species may weave
into web at more than
one level
• bears
• humans
– eating meat?
– eating plants?
Complete the Venn diagram about how organisms get
energy using these terms:
autotrophs
heterotrophs
both
Carnivores
Consumers
Decomposers
Herbivores
Producers
Are described by their energy source
Form the base of all ecological pyramids
Make organic molecules from inorganic molecules
Part of food chains and food webs
Some absorb their food from dead organisms
Some eat other organisms