•Biology 20Unit 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 landThe hydrosphere is the water

The atmosphere is the airLiving 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?

CellsTissuesOrgans

Organ systemsOrganism

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 habitatAir and water pollution

Climate changeUltraviolet 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