5 Major types:

• Overpopulation

• Depletion of Resources

• Pollution

• Global Changes

• Wars

Overpopulation - presence in a given area of more people that can be supported adequately by the resources available in that area.

Overpopulation is a major cause of all other environmental problems:

- The needs of everybody for food, water, & energy are not met and it will be worse.

- Human activities increasingly damage the environment because of air and water pollution, land degradation, and loss of biodiversity.

Consumption and Pollutants

A person in a rich country has a much higher consumption of resources and production of pollutants than a person in a poor country.

• Rich countries comprise 10% of world population,

• but consume ~ 90% of the world's resources

• and produce ~75% of the world's pollutants.

Resources : fuels, minerals, water, soil, timber depleted = used up

Depletion of resources in 3 ways:

1) substance can be destroyed, converted to smth else:

Examples: coal à ashes + gas;

U à radioactive waste products

2) substance is considered lost if it’s diluted (not usable):

Example: Iron ore is subject to mining (processing) if it contains >40% Fe (iron).

Scattered iron is not suitable for mining à iron resources are depleted.

3) substance becomes unfit for use by being polluted:

Example: Chemical wastes dumped into water à water unfit for drinking.

Pollution is a reduction in the quality of the environment by the introduction of impurities.

Examples:

• Smoke pollutes the air.

• Sewage pollutes water.

Give more examples…

Global Changes. Human activities affect the global environment.

Example:

CFCs (chlorofluorocarbons) used widely as refrigerants, sprays catalyze the destruction of OZONE O3, a chemical that protects life on earth from harmful radiation.

10% loss of ozone worldwide causes more skin cancer and cataracts.

Wars cause a combination of all possible environmental problems:

• air, water, soil pollution,

• nuclear war – radioactive waste,

• depletion of resources, etc.

2. Ecological units: life levels organization:

There are 10 levels of biological organization that differentiate by increasing in structural complexity and may also by unique property distinct from the structure.

1. SUBATOMIC PARTICLES – protons (‘+’ charge), neutrons (neutral: ‘0’ charge), and electrons (‘-’ charge).

2. ATOMS. It’s a fundamental unit of matter, smallest unit of a substance that retains the properties of that substance. 92 types of atoms found in nature. Each kind of atom forms a specific type of matter known as an element. Isotopes - atoms of the same element that differ in the number of neutrons they contain: Hydrogen, Deuterium & Tritium

3. MOLECULES. They consist of two or more atoms bonded together. Compound – a molecule made up of 2 or more kinds of atoms (elements) held together by chemical bonds

4. ORGANELLES and CYTOPLASM. This level of biological organization is the first one concerning living organisms. These structures are the components from which cells are constructed.

5. CELL. The smallest unit that is itself alive.

6. MULTICELLULAR ORGANISM. It’s an individual composed of many specialized cells.

7. POPULATION. It’s a group of organisms of the same species = all the members of a species that live in the same area and make up a breeding group. Species - a group of organisms that look alike and are capable of producing fertile offspring in the natural environment.

8. COMMUNITY: Populations of organisms living together in the same environment = all the populations in an area.

9. ECOSYSTEM: Dynamic system of organisms interacting with each other and the inanimate environment = is an ecological unit that includes all the interacting parts of an environment in an area (A. Tansley 1935).

10. BIOSPHERE: Entire surface of the earth and its organisms = is that area of the earth where life exists.

Water – Unique substance

~70% of the weight of living organisms

- Medium in which life's chemical reactions occur

- Water solutions – electrical conductors

- Highest surface tension

- Liquid over a wide temperature range

- Expands when it crystallizes, unlike most substances

- High heat of vaporization (latent heat)

- High specific heat