Download What is an Ecosystem? An ecosystem includes all the different

What is an Ecosystem?
An ecosystem includes all the different organisms living in a certain area, along
with their physical environment.
An ecosystem is like a car, all the parts work together to make the car move. If
one part breaks, the car may not run.
Ecosystems are not an isolated unit. They do not have clear boundaries.
Ecosystems are composed of two factors:
biotic factors: living parts of an ecosystem. Ex: animals, plants and micorganisms
abiotic factors: nonliving parts of the ecosytem. Ex: temperature, sunlight,
humidity, water supply and minerals
Ecosystem have a level of organization.
Organism (smallest)
Population
Community
Ecosystem
Biosphere (largest)
organism - an individual living thing
species - a group of organisms that are able to reproduce together and that
resemble each other in appearance, behaviour and internal structure.
Population - a group of individuals of the same species living in a particular place.
Community - a group of interacting populations of different species
Niche, and Habitat
Habitat- the place where the organism lives; the specific type of area in which
a plant or animal lives (on the planet).
Niche- the way of life of an organism. This includes the area where the
organism feeds, reproduces etc. It is biotic (living i.e. plants, other animals,
humans) resources
How Species interact with each other
Within an ecosystem, different species can affect each other negatively or
positively.
We will look closely at five major types of species interactions:
Predation
Competition
Parasitism
Mutualism
Commensalism
Predation, predator, and prey
the act of killing and eating another organism
i.e. a lion kills a zebra
the organism that kills and eats another organism is called the
predator
the organism that is killed and eaten is called the prey
Competition
the relationship between species that attempt to use the same limited resources
Animals compete for the limited resources available to them. Resources can
include food, sunlight, space etc.
Parasitism
the relationship between a parasite and its host
Parasites are organisms that feed on or live within another organism without killing
it immediately. However some parasites can lead to death.
Examples of parasites = tapeworm, ticks, fleas, leeches
The organism the parasite infects is called the host.
Can you think of any reason why the parasite may not want to kill its host?
Mutualism
A relationship between two species in which both species benefit
Ex. Anemones and clownfish are known to benefit from each other in an intimate
relationship. The clownfish becomes immune to the stinging nematocysts of the
anemone. The anemone provides protection and food scraps for the fish. The fish
lures other creatures into the anemone's tentacles and may also remove dead and
dying tissue from the anemone.
Commensalism
A relationship between two species in which one species benefits and the other
species is neither harmed nor helped.
Feeding Relationships, Three trophic levels
Each species in an ecosystem belongs to a certain trophic (feeding) level based on
their main source of nutrition.
In studying the feeding relationships between organisms, we are actually looking at
the living, or biotic, factors of the environment.
Producers
Consists of all plants, may also be called autotrophs.
Has the ability to make its own food through photosynthesis.
Supports all other feeding groups.
Makes up the greatest amount of biomass on the planet.
Eaten by consumers.
Consumers
consists of all animals.
These organisms are not able to produce their own food so they must find their
own food. They are also referred to as heterotrophs.
There are 3 orders of consumers:
1st order = herbivores eat the producers (plants) i.e cow, sheep, deer etc
2nd order = carnivores eat other consumers (animals) i.e. lions, hawks, foxes etc
3rd and 4th = feed on other carnivores in the environment i.e. killer whales
Humans are considered omnivores because we eat both plants and animals. Bears,
pigs and other animals are also omnivores because they eat both.
Decomposers
Life forms that live on dead, dying or decayed plant and animal matter.
Mostly consist of fungi and microscopic organisms, such as bacteria. Scavengers
like ravens, crows etc help decomosers by breaking down dead material.
Essential to the natural environment. They help to recycle nutrients back into the
ecosystem.
They break down animal excretions and dead organisms into simpler components
that can be taken in and reused by producers.
Food Chains
Food chains can be written in a number of different ways, the simplest is: Sun 
producers  consumers
Food Webs
All of the possible feeding relationships within an ecosystem are shown
using a food web.
Summary of food webs and food chains
Within ecosystems there are producers, consumers and decomposers who transfer
energy to one another through food chains or food webs.
Trophic Level = the level in the food chain that an organims occupies. It can be
producer, consumer, primary consumer, etc.
Producers are the 1st trophic level and contain the most energy and each
subsequent level has less and less energy.
Food Chain = simplified way to show which organisms eat one another.
Food web = represents all possible food interactions that can occur between certain
organisms
Optimal Living Conditions
Each species will respond differently to these abiotic factors. The way that they
respond determines where they will live. Different species will do well under
different conditions.
Every organism has an optimum, a level they thrive at. This is called the optimal
zone. i.e. a good amount of water, sun etc.
There is also a point where life is not possible. A high and low end of this range of
optimance and this is the limit of tolerance. If an organism reaches this point they
cannot survive. The stress is too much for them.
Zones of stress exist between the optimal environmental and the high and low
limits. The organism would experience levels of stress as they become closer to
their tolerance limit.