I. the 3 Cycles of Life

I. the 3 Cycles of Life

The Environment

Chap. 11 and 18

I. The 3 cycles of life

The Water Cycle – the continuous movement of water beween Earth and the atmosphere.

  • evaporation – the change of liquid water to water vapor
  • transpiration – the release of water vapor into the atmosphere by plants and algae
  • condensation – the change of water vapor back into liquid water as the water vapor cools
  • precipitation – when water falls back to Earth
  • ground water – water that is stored in the ground

The Carbon Cycle – the movement of carbon from nonliving things to living things and back.

1. Photosynthesis – removes carbon from atmosphere when plants take in carbon dioxide to make sugars. animals get their carbon

from eating plants

2. Respiration – returns carbon to the atmosphere from plants and animals carbon dioxide and water are byproducts from the

breakdown of sugars into energy

3. Decomposition – the breakdown of dead organisms releasing carbon dioxide and water.

Bacteria and fungi return carbon to the soil and air when they decompose organic matter.

4. Combustion – the burning of oils, coal, and natural gas

The Nitrogen Cycle – the movement of nitrogen from the nonliving environment into living things and back.

  • 78% of atmosphere is nitrogen
  • Organisms need nitrogen to build protein and DNA
  • Nitrogen fixation – the changing of nitrogen into a usable form by bacteria in plant roots.
  • Animals get nitrogen from eating plants
  • Nitrogen also returned to atmosphere when bacteria break down dead organisms and waste.

II. Environmental Problems

Pollution – the presence of dangerous levels of substances in the environment

  • Come in many forms, harm and kill plants and animals, natural or man-made.
  • Garbage – hazardous waste seeps into the soil and ground water from landfills
  • Chemicals
  • chemical pesticides
  • chlorofluorocarbons (CFCs) – affect the ozone layer and are banned
  • PCBs – also banned
  • Radioactive waste – produced by nuclear plants, mining operations, industry, and hospitals
  • releases radiation and takes hundreds of years to break down

Resource Depletion

  • Renewable resources – resources that can be used over and over or that have an unlimited supply

can become nonrenewable such as the rain forest and rich soil

  • Nonrenewable – resources that can not be replaced or that would take thousands of years to replace.

minerals, fossil fuels, petroleum

  • Alien species – organisms that make a home for itself in a new location.

often become pests and predators

  • Human population growth

Human population is headed towards 14 billion by 2100.

Some believe not enough resources to support growth

Habitat Destruction – when an organism’s habitat is destroyed or threaten by clearing land, construction, etc.

  • Deforestation – the destruction of forests
  • Wetlands – filter pollutants, control flooding, are habitats for many organisms, and restore ground water

drained to provide land for construction

  • Marine – oil spills and plastics contaminate the water and harm animal and plant life
  • Humans – polluted water, chemicals in the soil, depleted resources.

III. Solutions

Conservation – preservation and wise use of natural resources

Reduce – use less natural resources

  1. use biodegradable packaging
  2. alternative fuels such as solar and wind energy
  3. turning off lights, riding bikes, etc.

Reuse – reusing plastic bags for example

Recycle – breaking down materials to make other materials

  1. plastics, paper, aluminum cans, glass

Maintaining biodiversity

  1. Protecting species
  2. Protecting habitat

Chapter 18 Notes

There are two types of water pollution:

a. Point-source Pollution – pollution that comes from a single or easily traced source such as a

broken sewer pipe. This type of pollution is easy to control.

b. Nonpoint-Source Pollution – pollution that can come from many sources. Most reach bodies of

water by runoff.

Water Pollution

Freshwater Pollution

1. Surface water if often polluted by waste from cities, factories, and farms.

2. Some major pollutants are fertilizer runoff, landfills, factory waste, and pesticides

3. Clean water Act and the Safe Drinking Water Act were enacted in the 70’s to protect our surface water

and our drinking water

Ocean Pollution

1. Most pollution is Nonpoint-source pollution due to human activity along rivers and streams.

2. Other sources are trash, sludge dumping, and oil spills.

3. In 1972 the Marine Protection, research and sanctuaries Act was enacted to protect our ocean waters.

4. Citizens are now organizing groups that help keep our beaches and oceans clean.

Air Pollution

1. There are many natural pollutants that pollute our air, but we are used to them.

2. Humans create most of the pollution that we hear about though

3. Pollution can be a solid, liquid, or a gas and most often occur in cities.

Types of Air Pollution

1. Primary Pollutants – pollutants put directly in the air by humans or natural activity

2. Secondary Pollutants – are pollutants that form from chemical reactions between primary pollutants.

3. Many form when primary pollutants react with sunlight to form pollutants such as smog and ozone.

Sources of Human-Caused Air pollution

1. Major cause of air pollution is transportation that is fuel by fossil fuels

2. Factories that burn fossil fuels for energy add oxides and chemicals to the air.

3. Pollution inside can be worse than the pollution outside because of cleaners, smoking products, paint,

etc.

Air Pollution Problem

1. Air pollution can be blown from its source to another area and create problems in the new area.

2. Acid precipitation is rain, sleet, or snow that has become acidic after it has come in contact with burning

fossil fuels.

Sulfuric and Nitric Acid forms when the oxides combine with water.

3. Global warming and the hole in the Ozone Layer are created when chemicals cause the ozone to break

down into oxygen.

4. Pure air quality can affect people who have allergies, respiratory problems and heart problems.

Solutions to Air Pollution

1. The Clean Air Act was enacted in 1970 to allow the EPA to regulate and control the amount of pollutants

that are released into the air.

2. EPA now has set standards of emission for car exhaust and require factories to remove pollutants from

the gases they release.

Saving Our Soil

1. Soil is being lost due to erosion at faster rate than it is being created.

2. Soil can be lost naturally, but human activity speeds erosion.

3. Plant life is needed to keep soil in place.

4. Farming, overgrazing, and deforestation can speed up erosion.

Three types of Erosion

1. Sheet erosion – occurs when surface water moves downslope and erodes topsoil evenly

2. Rill erosion – surface water forms tiny grooves called rills in the soil.

3. Gully erosion – surface water erodes channels or gullies, in they soil.

Deforestation

1. The clearing of forest

2. This makes the soil infertile and unusable

3. Usually it involves overgrazing or bad farming practices.

4. Creates deserts or desert like areas that cause an increase in erosion.

Soil Conservation

1. Include practices that decrease soil erosion, increase the amount of water that is absorbed by the soil, and

prevent the loss of soil fertility

2. Contour farming, strip farming, and windbreaks are methods of soil conservation.

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