1. Introduction to Ecology
Packet #79
Chapter #52

2. Introduction
Ecology
The scientific study of the interactions between organisms and the environment
Ecologists, under the umbrella of ecology, pose questions and devise hypotheses about ecosystems.
Where does a species of organisms live?
Why do they live there?
How many of those organisms are there?

3. Ecosystem
Complete community of living organisms and the nonliving materials of their surroundings
Consists of
Biotic components
Living organisms
Abiotic components
Non-living factors
Light
Temperature
Water

4. Levels of Ecological Study
Organismal Ecology
Study of individual organisms’ behavior, physiology, etc.
Population Ecology
Study of populations in relation to the environment
Environmental influences
Population density and distribution
Age of members
How do populations grow? Is there a limit to the number of organisms within a population?
Community Ecology
Study of interactions between organisms, of various populations, at a particular site or in a specific area
Ecosystem Ecology
Study of movement of energy and matter through ecosystems

5. Man, His Environment & Impact on Ecosystems

6. Question
How would you describe the major human influences on the environment?
Primitive man
Affected environment
Hunting
Fishing
Removing trees for fires and shelters
There was a demand for land to cultivate and harvest crops and to grow communities
Cultivation of crops done with domestic animals and they had to be fed as well
Leaving less for human consumption
More modern man
Discovery of fossil fuels
Machines were now used to help grow more crops
Population became larger
Fertilizers, pesticides and “rapid” transportation developed
Brought the problem of pollution
Nuclear energy was developed with its consequent environmental problems

7. Exploitation of Natural Resources
Agriculture
Fire used to clear large areas of land for planting
Vegetation destroyed and replaced by mono-culture
Field of cereal crops replaced a forest of oak
Placed a demand on soil nutrients after growing same crop for a number of years
How could this problem be avoided?
Rotating crops
Excess use of fertilizers
Caused pollutants to run off into rivers due to leaching and draining
Weeds and pests also compete for resources and with only one main species as competition, soil nutrient problems also arise

8. Renewable Resources
Renewable resources are basically things that grow and are therefore replaced.
Does not mean that the resources are inexhaustible
If the resource is utilized too much, at too much of a great rate, they will most certainly diminish and even disappear altogether
Reason why there are harvesting seasons
Lobster
Crab
Salmon
What is your opinion on how man has utilized these renewable resources?

9. Non-renewable Resources
Not replaceable
Oil
Gas
Coal
Mineral ores
Will oil and gasoline run out?
Some believe so!

10. Human Population Explosion
Questions posed by scientists?
Will the human population reach it’s carrying capacity?
The explosion in human population has resulted in: -
An increase in the use of non-renewable resources
An increase in land, air and sea pollution as a result of fuel combustion by-products
Today, finding a cost effective measure, where resources are not totally used up, is not easy and there are many arguments between conservationists and industry

11. Looking Ahead

12. A Look Ahead
In future packets, we will investigate many of the faucets of ecology and ecosystems.