Transcript Ecology Unit

Ecology Unit
Introduction to Ecology
Part I
What is Ecology?

Greek oikos meaning “house” and logos
meaning “ Study of”

Named in 1866

Is the study of the interactions between
organisms and the living and nonliving
components of their environment
What is Interdependence?

Organisms that are dependent on one
another and their environment
 Interdependence is a key theme found
throughout ecology
– Example 1: you could not survive without the
plants and other photosynthetic organisms that
produce oxygen
– Example 2: Plants could not survive without
carbon dioxide (essential raw material for
making carbohydrates by photosynthesizers
Effects of interdependence:

Any change in the environment can spread
through the network of interactions and affect
organisms that appear far removed from
change
– Large acorn production can support large deer
and mice populations. Tick feeds on animals,
so they increase; increasing the chance of
humans being bit (Lyme disease)
Levels of Organization in
Ecology

1. The Biosphere:
– The broadest level of organization
– The thin volume of Earth and its atmosphere
that supports life
– Where all organisms are found
– 13 miles thick (if the Earth was the size of an
apple, the biosphere would be the thickness of
its skin)
Levels of Organization in
Ecology

2. Ecosystems:
– Includes ALL of the organisms and the
nonliving environment found in a particular
place
– Organisms in every environment directly or
indirectly affect one another.
– Chemical composition will also affect species
in every ecosystem
Levels of Organization in
Ecology

3. Communities:
– Includes only species of organisms
– Is all the interacting organisms living in an
area
 Ex: Fish, turtles, plants, and bacteria in
the pond that makes up a community
Levels of Organization in
Ecology

4. Populations:
– Includes all members of a species that live in
one place at one time
 Ex: Population of California poppies
(flowers) in a specific area of California
Levels of Organization in
Ecology

5. Organisms:
– Is the simplest level of organization in
ecology
– Research concentrates on the adaptation that
allows organisms to overcome the challenges
of their environment
Biotic vs Abiotic Factors:

Abiotic Factors:
– The physical and chemical aspects of the
habitat
– They are all the nonliving factors
– Include: temperature, humidity, pH salinity,
oxygen concentration, sunlight, nitrogen,
and precipitation (water)
– These factors vary from place to place
Biotic vs Abiotic Factors:

Biotic Factors:
– All the living components of the environment
– Include all living things that affect the
organism
Biotic vs Abiotic Factors:

***Draw and Label four abiotic and biotic
factors***
Niche:

What is a niche’s meaning?
– French nichier, meaning “to nest”

What is a niche?
– Is the specific role, or way of life, of a species
within its environment
Niche:

Niche includes the following:
– The range of conditions that a species can
–
–
–
–
–
tolerate
The resources it uses
Methods by which it obtains its resources
The number of offspring it has
Time or reproduction rate
And all other interactions within its
environment
Niche:

Some species have more than one niche in
their lifetimes:
– Ex: Caterpillars eat leaves of plants. As an
adult, butterflies feed on nectar
Two classes of a niche:

Generalist:
– Are species with broad niches
– They can tolerate a range of conditions and use
a variety of resources
 Ex: Virginia opossum – found across most
of the U.S. Feeds on almost anything.
Two classes of a niche:

Specialists:
– Have very narrow niche

Example: Koala, in Australia, only feed on
the leaves of a few species of eucalyptus
trees
Niche

***Draw and label a niche***
Key questions/concepts to
review

Explain why interdependence is an
important theme in ecology?
 Describe one example of the effects of
interdependence upon organisms in their
environment?
 List and describe the key components of the
5 main levels of organization in ecology
Key questions/concepts to
review

Why is the amount of sunlight important to
the animals in an ecosystem?

Assuming wolves eat deer, how could a
disease that kills a large portion of the wolf
population affect the mice population in a
forest ecosystem?
Key questions/concepts to
review

Distinguish between biotic and abiotic
factors. List several examples

Compare generalists to specialists
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How does an organism’s niche differ from
its habitat
Key questions/concepts to
review

Why do different species never occupy
exactly the same niche?

If some of the resources in a habitat are
destroyed, which would be more likely to
survive, a generalist species or a specialist
species? Explain your answer