Ecology UnitEcology UnitIntroduction to Ecology

Part I

What is Ecology?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?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: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 Levels of Organization in EcologyEcology

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 Levels of Organization in EcologyEcology

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 Levels of Organization in EcologyEcology

3. Communities:– Includes only species of organisms – Is all the interacting organisms living in an

areaEx: Fish, turtles, plants, and bacteria in

the pond that makes up a community

Levels of Organization in Levels of Organization in EcologyEcology

4. Populations:– Includes all members of a species that live in

one place at one timeEx: Population of California poppies

(flowers) in a specific area of California

Levels of Organization in Levels of Organization in EcologyEcology

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: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 vs Abiotic Factors:

Biotic Factors:– All the living components of the environment– Include all living things that affect the

organism

Biotic vs Abiotic Factors:Biotic vs Abiotic Factors:

***Draw and Label four abiotic and biotic factors***

Niche: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:

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: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: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: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

NicheNiche

***Draw and label a niche***

Key questions/concepts to Key questions/concepts to reviewreview

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 Key questions/concepts to reviewreview

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 Key questions/concepts to reviewreview

Distinguish between biotic and abiotic factors. List several examples

Compare generalists to specialists

How does an organism’s niche differ from its habitat

Key questions/concepts to Key questions/concepts to reviewreview

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