lunes, 21 de febrero de 2011

Species Approach

When there are no more animals of a particular species left alive, that species is said to be extinct.

In the distant past, several species of animals became extinct through natural causes. There might have been a change in the climate of a particular region, and the plants or animals on which the species lived could have died out because of the change in the weather. Or one animal might have been destroyed by another that was stronger or faster.

But ever since human beings have been on Earth, and especially in the last hundred years, animal species have become extinct because of hunting, pollution, or the destruction of the places where they live.

So many animals are now in danger of extinction that a list is kept in a Red Book. unfortunately, the list gets longer every year.

Characteristics of animals prone to extinction

Endemic species

  • Low reproductive rate
  • Specialized niche
  • Feeds at high trophic level
  • Fixed migratory level
  • Commercially valuable

Invasive species vs. Ecosystem

Invading species success because:

  • High reproductive rate
  • Wide life span
  • High dispersion rate

The new ecosystem is adequate because there are not direct depredators, the climate conditions are the correct ones.

Disadvantages:

  • You just focus your efforts in just one species
  • Not holistic
  • ‘Cause not all the variable are considered you could miss a higher priority
  • Connections between species, biotic and abiotic factor cannot be ignored

martes, 1 de febrero de 2011

Photochemical smog

Photochemical smog is a type of air pollution produced when sunlight acts upon motor vehicle exhaust gases to form harmful

Irritates the eyes a

Peroxyacetylnitrate. Nitrogen dioxide, oxygen and hydrocarbons react with the sunlight.

Catalytic Converters.Is a strategy that tries to reduce the emission of carbon monoxide and nitrogen oxide production. It uses platinum or radium  (reduce the amount) The unburned hydrocarbons are catalyzed to produce carbon dioxide and water vapor. 

The catalytic convertors needs to promote the necessary rate of acting over the combustion, reducing first the nitric oxide to nitrogen gas to avoid the oxidation of the carbon dioxide

The ozone Is form outside the combustion chamber when the nitrogen oxide (NO2) is divided between nitrogen and oxygen. Then the oxygen reacts with other particles of oxygen in the air to form ozone.