Introduction to Ecology

What is Ecology

• The study of how organisms interact with their environment

• All organisms must interact with both living and nonliving things that surround them

Levels of Organization

• To add to our list of the levels of organization:– Cells Tissues Organs Organ

Systems Organisms Population Community Ecosystem Biosphere

The environment

• Made up of all the living and nonliving things that surround an organism.

• Vocabulary:– Abiotic Factors– Biotic Factors

Environment vs Habitat

• Many species can survive in more than one environment.

• But each species has its “home” or habitat. – Fish may be able to

live in fish tanks, but would rather live in the wild

Basic Concept of Ecology

• The fundamental idea behind the study of ecology is that all organisms are interdependent.

• They interact with one another and the physical environment.

What do organisms need to survive?

• Basic requirements for survival include:– Food – Water– Shelter

Competition

• An important aspect of the struggle for survival involves competition for limited resources– Food– Water – Shelter– Sunlight

Limiting Factors

• Limiting factors are factors that affect the population size of a species in a specific environment.

• They can be abiotic or biotic.

Predator – Prey relationship

• Predators are a biotic limiting factor.

• They control population size by feeding on prey.

• There is a delicate balance that needs to be maintained.

Carrying Capacity

• When all the limiting factors are considered together we can determine the maximum number of organisms that can survive in an area.

How do we determine the Carrying Capacity of a

Species?• All limiting factors

must be taken into consideration.

• It is very difficult to determine the actual carrying capacity.

The Lesson of the Kaibab Deer

• Purpose: – to graph data on the

Kaibab deer population of Arizona from 1905~1939

– to analyze the methods responsible for the changes in the deer population

– to propose a management plan for the Kaibab deer population

Kaibab Forest: North Rim of the Grand Canyon

Key Idea

• All organisms have the ability to produce populations of unlimited size

• But their environment keeps their numbers in check.

Review of Types of Nutrition

• Autotrophic• Heterotrophic

Which is heterotrophic and which Autotrophic?

Categories of Populations

• Populations are labeled by the function they serve in the ecosystem – Producers– Consumers– Decomposers

So what is a Food Chain?

• A food chain shows a one way flow of energy in an ecosystem

• It may not be the only way energy flows in the ecosystem

Food Webs

• When all of the food chains of an ecosystem are considered we can draw up a food web

• It shows all of the possible paths that energy can take in an ecosystem

• It also shows how organisms are dependant on each other in the ecosystem

Recycling

• Who is ultimately responsible for the recycling of nutrients? – Decomposers

• What gets recycled?– Minerals – Nutrients

Recycling

• What else gets recycled?– Carbon Dioxide– Water– Carbon

• The energy from the Sun keeps the cycle going

Carbon Cycle

Water Cycle

Nitrogen Cycle

Energy Pyramid

Energy Pyramid

• There is more energy available at the bottom

• There are more organisms at the bottom

• There is less energy at the top• There are less organisms at the top• Energy is lost as you go up the

pyramid, mostly as heat

Energy Pyramid!!!