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•Biology 20
Unit A: Energy and Matter Exchange in the
Biosphere.
Chapter 1: The Biosphere as a Closed System
Joy in looking and
comprehending is natures
most beautiful gift.”
Einstein
“
There is nothing
puerile in nature; and
they who become
impassioned of a
flower, a blade of
grass, a butterfly’s
wing, a nest, a shell,
wraps their passion
round a small thing
that contains a great
truth”
Maeterlinck
“
What is meant by the term biosphere?
 The narrow zone around the earth that
harbours life
Can you name any or all of the three basic
structural zones that make up the biosphere?
 The lithosphere is the land
 The hydrosphere is the water
 The atmosphere is the air
Living organisms are found in all three zones!
Our biosphere is in a state of dynamic
equilibrium.
What does this term mean?
 Any system in which changes are
continuously occurring but whose
components have the ability to adjust to
these changes without disturbing the entire
system
 Today’s ecologists have evidence to suggest
that Earth is facing a crisis in which its
dynamic equilibrium is being upset
The limits of the biosphere extend from the
ocean depths all the way to the atmosphere.
Most of the terrestrial animals are confined to
a narrow band where the atmosphere meets
the surface of the earth.
The regions that are not within the biosphere,
such as the upper atmosphere and the Earth’s
core are also important because they affect
living organisms.
The biosphere consists of both biotic and
abiotic components. Can you define these
terms?
 Biotic: the biological or living components
of the biosphere
 Abiotic: The non-living components of the
biosphere. Chemical and geological
factors, such as rocks and minerals, and
physical factors, such as temperature and
weather make up the abiotic components.
Ecologists use a system of organization that is
similar to the organization of life forms that
you are already familiar with. What system do
biologists use when discussing complexity
within an organism?
 Cells
 Tissues
 Organs
 Organ systems
 Organism
Levels of ecological organization
 Individuals: A single member of a species
 Populations: members of the same species
occupying a given area at a certain time.
 Community: The populations of all species
that occupy a habitat.
 Ecosystem: a community and its physical
and chemical environment.
Biodiversity: it is all about sex!
In your own words, define biodiversity.
 The number and variety of organisms living
in a given ecosystem.
Food Chain: a sequence linking organisms
that feed on each other, starting with a food
source and continuing in order with each
consumer.
Producer:
 An autotroph; an organism that makes its
own food.
Consumer:
 A heterotroph; an organism that must eat
producers or other consumers to survive.
Types of Consumers:
Herbivore: an animal that eats only plants
Carnivore: an animal that feeds only on other
animals
Omnivore: an animal that eats both plants
and other animals
How is waste recycled in an ecosystem?
Detritus: waste from plants and animals,
including their dead remains
Decomposer: an organism that feeds on
detritus
Equilibrium Unbalanced 1.2
When the dynamic equilibrium of an ecosystem
becomes unbalanced for any reason, the health
or numbers of organisms in that ecosystem are
affected.
In Canada, more than 450 species of plants and
animals are at various degrees of risk, and 12
species have become extinct.
Classification of degrees of risk:
An endangered species is one that is close to extinction
in a significantly large geographical location.
An extirpated species is one that no longer exists in a
specific geographical location.
A threatened species is any species that is likely to
become endangered if factors that make it vulnerable
are not reversed.
Special concern refers to any species that is at risk
because of low or declining numbers at a fringe of its
range or in some restricted area.
Within an ecosystem, there are species that are
very sensitive to changes that occur. These
species are known as indicator species.
Why might amphibians be good examples of
indicator species?
 They occupy both aquatic and terrestrial
ecosystems.
 They are also part of two very different food
chains. Adult frogs eat mostly insects and a few
small fish. In turn, large fish, predatory birds,
reptiles, and small mammals eat frogs.
How might the disappearance of frogs have an
effect on the ecosystems they occupy?
Even though amphibians have been on earth
for more than 400 million years, they seem to
be on a rapid decline.
At your table, come up with some possible
reasons for this.
 Loss of habitat
 Air and water pollution
 Climate change
 Ultraviolet radiation
Read pages 13 and 14 in your text
This we know: The Earth
does not belong to us: we
belong to the earth.
This we know: All things are
connected like the blood
which unites one family. All
things are connected.
Whatever befalls the earth
befalls the sons and daughters
of the earth. We did not
weave the web of life, we are
merely strands in it. Whatever
we do to the web, we do to
ourselves.
Chief Seattle, 1854