ECOLOGYSymbiotic Relationships
COMPETITION Species living in the same habitat
may use the same resources. These species will compete for the
resource.
PREDATION A relationship between two species
Predator: captures and feeds on the other organism Prey: is the one that gets eaten.
In ecology this relationship is a form of population control. If there are not enough predators, too many
prey will exist, and vice versa
SYMBIOSISAny relationship in which two organisms live closely togetherMeans “living together”Three main classes of symbiotic relationships
PARASITISMIn a parasitic relationship one organism lives in or on another organism(the host) and harms itThe parasite gets its nutritional requirements from the host
The host is weakened, but usually does not die
PARASITISM
MUTUALISMBoth organisms benefit from the relationship.
MUTUALISM
COMMENSALISMOne organism benefits from the relationship while the other organism neither benefits nor is harmed
COMMENSALISM
ECOLOGYFood chains and food webs
TROPHIC LEVELSA trophic level is one of the steps in a food chain or pyramid
LEVEL ONEThis level is always the producers
Producers are organisms that first capture energyAka: autotrophs
Ex: plants, algae, some bacteria
CONSUMERSAn organism that consumes plants or other organisms to obtain energy
Consumers make up the rest of the trophic levels
Aka heterotrophs
LEVEL TWOThis level consists of herbivores-organisms that eat plants
Consumers on this level are called primary consumers
LEVEL THREEThis level consists of carnivores- organisms that eat other organisms for energy
They are called secondary consumers
LEVEL FOURConsumers on this level are called tertiary consumers
They are carnivores who eat other carnivores
OTHER ORGANISMS IN A FOOD WEB Detritivores-an organism that feeds on
organic waste Omnivores- organisms that eat both plants
and other organisms Decomposers- An organism who recycles
nutrients by feeding on dead or decaying organisms.
DetritivoreDecomposer Omnivore
WHAT IS THE DIFFERENCE BETWEEN A DETRITIVORE AND A DECOMPOSER?They both obtain energy from organic
matter (dead/decaying plants and animals), but…
The way they consume the organic matter is differentDetritivores actually eat the organic
matterDecomposers secrete enzymes that
break down the organic matter into small molecules and then consume those small molecules
FOOD CHAINA path of energy through the trophic levels of an ecosystem
FOOD WEBA diagram that shows the feeding relationships between organisms in an ecosystem
QUESTION:How are food chains and food webs related?
Several food chains make up a food web
TYPES OF FOOD WEBS Grazing food web: starts with plants in
the first trophic levelPlants get their energy from the sun
Detritus food web: starts with dead organic matter such as plants or animals
ENERGY LOSSAs you go up each trophic level energy is lost
Most energy is lost to the environment as heat
An organism stores about 1/10 of the energy stored by an organism in the level below it
ENERGY LOSS
The first trophic level starts with 100% energy.
200X .01 (10%)
20
2
0.2
PYRAMID OF BIOMASS
The decrease in energy going to up in levels means that there is less energy for animals to survive on.
Less energy means less animals.
This is referred to as a decrease in biomass