2.1 Ecosystem Structure
Living and Nonliving Components In Ecosystems
Abiotic – Non-living
Water
Air
Nutrients
Rocks
Heat
Solar energy
Wind
Biotic- Living
Any living or once
living
Biotic and Abiotic Components of an Ecosystem
Fig. 3-6, p. 59
Ecologists Study
Interactions in Nature
Ecology- Study of how organisms interact with each other
and their environment
Habitat-An environment where a species lives
Niche- How an organism makes a living (role/job)
Biosphere
Parts of the earth's air, water, and
soil where life is found
Ecosystem A community of different species interacting with
one another and with their nonliving environment of
matter and energy – All biotic and abiotic factors
together
Community Populations of different species
living in a particular place, and
potentially interacting with each
other
Population
Species
A group of individuals of the same
species living in a particular place
A particular type of organism
Organism
An individual living being
Cell
The fundamental structural and
functional unit of life
Food Chain vs. Food Web
Food Chain – shows flow of energy from one
organism to another
Food web - shows flow of energy interconnected to
many organisms (all possible food chains)
Food Chain vs. Food Web
Lake Michigan Food Web
Trophic Levels
Trophic Level = feeding level (position of an organism on
a food chain)
Producers
• Producers- autotrophs which are
• “self-feeders”
• Plants Perform Photosynthesis
• Use sun energy to make their
own
• Food Waste product is oxygen
Consumers
Consumers- (heterotrophs
“other feeders”) – Organisms that
obtain nutrients from living things
Primary consumers = Herbivore
(eats plants)
Secondary consumers – Carnivores
Eat the primary consumers
Fig. 3-8a, p. 60
Decomposer
Detritivores (scavenger)
Feed on dead bodies of other
organisms
Ex. Earthworms, Vultures
Decomposers
Consumers that release nutrients
Ex. Bacteria, Fungi
Detritivores and Decomposers
Fig. 3-10, p. 61
Review of Terms
Ecological Pyramids
Pyramids show differences that exist between trophic
levels
Always a decrease of energy and biomass when
moving up a pyramid
10% Rule: ~10% of the energy from the one level is
passed to the next level
~90% of energy is used released as heat (respiration)
Three types of pyramids (biomass, numbers, energy)
Pyramid of Biomass
Biomass (g m -2)
Dry weight of all organic matter of a given trophic level in a food
chain or food web
Pyramid of Energy
Pyramid of energy flow (J m-2 yr-1)
Less chemical energy for higher trophic levels
Pyramid of Numbers
Pyramid of numbers
Shows the total number of organisms at each trophic level
Snapshot in time
Pyramid structure
Bioaccumulation- concentration of toxins increases
in an individual organism’s tissues
Biomagnification- concentration of toxins increases
as the trophic level increases
Biomagnification of DDT
What is DDT?
Dichlorodiphenyltrichloroethane…that’s why we call
it DDT!!
Insecticide used to fight malaria
Started in 1948 to kill mosquitoes and fight spread of
malaria
Stored in the fats of organisms, and biomagnifies
through the food chain
Predatory bird populations suffered
Banned in the US in 1972
Population Interactions
Competition (- / -)
Two or more organisms in the same community seek the
same resource at the same time.
Two types
Interspecific – between two different species
Intraspecific- within an individual species
Resources must be in limited supply (food, water, light,
shelter, space, mates)
Mountain goat competition for mates
Inter or intra???
Predation ( + / -)
One species killing another and consuming it in the
process
Lions prey on wildebeests in Africa
Herbivory (+/-)
Consumption (grazing) of producers by primary
consumers
Caterpillar eating leaf
Parasitism (+/-)
Organism that lives on or in another host
organism
Parasite benefits and host is harmed
Tapeworm in human intestine
Mutualism (+/+)
Both organisms benefit from interactions
Best example is Lichen
Lichen is algae and a fungus
Fungus provides structure and algae provides food
source
Commensalism (+ / 0)
One organism benefits and the other organism is not
affected
Clownfish and the sea anemone
Ammensalism (- / 0 )
One species is harmed and another species is not affected.
Ex. Algae blooms can lead to the death of many species of
fish, however the algae do not benefit from the deaths of these
individuals.
Neutralism (0 / 0)
Two organisms do not affect each other
Essentially they have no relationship
Dandelions and salmon in a ecosystem (have little or no
effect on each other