our big beautiful blue planet is in a
complicated balance of life and death
predator and prey friend and foe
the word ecology literally translates to
the study of home our home planet earth
the more specific definition of ecology
is the study of the relations of
organisms to one another and to their
physical environment
it answers questions like how do living
things interact and rely on each other
or on their surroundings
the survival of any species is dependent
on other living organisms and non-living
components
this is called interdependence for
example humans could not survive without
plants to produce oxygen and the plants
need carbon dioxide from humans and
other organisms or even from volcanic
eruptions
ecology is extremely complex and
difficult to study so one way that
ecologists deal with this complexity is
to use ecological models to represent or
describe the components of an ecological
system
this model is called an ecosphere
the largest ecological system we know of
is the biosphere planet earth this is
the only biosphere we study because so
far it's the only place in the universe
that we know has life the biosphere is
the thin veil on earth that goes from
above the ground to the deepest parts of
the ocean
all life on earth is in the biosphere
if you zoom into one ecosystem it's a
little easier to see all the parts
working together an ecosystem is all the
organisms in non-living environment
found in a particular place the living
things in this pond ecosystem include
fish turtles aquatic plants algae
insects birds and bacteria these
organisms interact in ways that affect
their survival for instance insects and
fish eat aquatic plants and the turtles
eat the fish
the non-living or physical and chemical
things include the chemical composition
of the pond its ph its levels of
dissolved oxygen and carbon dioxide and
its supply of nitrogen which all help to
determine what kinds of organisms live
in the pond and how abundant they are
a community
is all of the interacting organisms in
an area
it does not include the non-living
factors
a population is all of the organisms of
one type of species in the area and an
organism refers to an individual animal
in order the levels of organization from
the most broad to the narrowest are the
biosphere
ecosystem community
population and organism
when we talk about where an organism
lives instead of saying ecosystem which
might still be a fairly large area we
could talk about its habitat it's just a
word that means the place where an
organism lives
a habitat includes both biotic and
abiotic factors biotic factors are the
living parts of the habitat and when you
add the letter a in front of the word it
means not living so abiotic factors are
the non-living parts of the habitat
using the pond ecosystem as an example
biotic factors include grasses algae
fish birds and insects the abiotic
factors include the ph of the water
rocks soil the sunlight and temperature
now you may sometimes hear people try to
use the word habitat and the word niche
interchangeably and that's not quite how
they should be used a niche is the job
or role of the organism within its
environment so habitat is a home a niche
is a job for example a redwood tree
takes energy from the sun and turns it
into sugar using photosynthesis
redwood trees are often found in foggy
coastal areas like santa cruz california
the habitat is the foggy coastal areas
like california and the niche is
converting the sun's energy into sugar
by photosynthesis
now some organisms fill a very broad
niche and some a very specific one
generalists eat a variety of foods and
specialists eat few or even just one
type of food pigs are an example of a
generalist they'll eat lots of different
foods very happily this can be
beneficial to them because they could
survive on a variety of foods and fill a
niche in many different habitats
the panda on the other hand is a
specialist because they only eat bamboo
if bamboo is unavailable the panda
population may die off this species has
a much higher risk of becoming extinct
so it's often beneficial for organisms
to be generalists
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