Atmosphere, Biology

Atmosphere is a multilayer blanket of various gases such as N2 (78.80%), O2 (20.95%), Ar(0.93%), CO2 (0.03%), water vapor and some other gases. This envelope extends from earth's crust up to a distance of 1000 km.

It behaves like an insulator preventing the escape of heat from earth surface, filters harmful UV. Rays, and helps in stabilization of weather and climate. On the basis of composition and temperature atmosphere is divided into five layers.

(a)    Troposphere

(b)   Stratosphere

(c)    Mesosphere

(d)   Thermosphere

(e)    Exosphere

 

(A). Troposphere:

It is lower most layer of the atmosphere and extends up to height of 12-18 km. it contains about 75% of total atmospheric mass. Formation of clouds, storms and thermal convection (weather and climate changes) occur in this layer. The approximate decrease of temperature is 6 C with 1 Km increase in the height.

 

(B). Stratosphere:

It extends up to 50 km. This layer is rich is ozone gas which is present in ozone sphere. Here, ozone is formed by decomposition oxygen to atomic oxygen by solar radiation and combination with oxygen to from ozone.

            O2 + Solar rays = 2O

            O2 + O = O3

Ozone layer acts as a protective umbrella to absorb the UV rays of the sun.

 

(C). Mesosphere:

It starts above the stratosphere and extends to an altitude of 85 km. This layer is characterized by fall of temperature due to absence of radiation absorbing species (ozone). Temperature may reach as low 93 C with increase of altitude. Main chemical species present here as N2, O3, O2+ and NO+.

 

(D). Thermosphere (Ionosphere):

It extends up to a height of 500 km from surface of earth and is characterized by increase in temperature with height. In this sphere U.V. radiation and cosmic rays causes ionization of molecules and thus Components like O2+, O+ and NO+ is formed. These ions reflect back radio waves back to earth surface and enable us to have wireless communication.

 

(E). Exosphere:

It is upper most layers and extends up to height of 1600m from earth surface. It has very high temperature and contains H2 and He.

Posted Date: 7/11/2012 3:35:22 AM | Location : United States







Related Discussions:- Atmosphere, Assignment Help, Ask Question on Atmosphere, Get Answer, Expert's Help, Atmosphere Discussions

Write discussion on Atmosphere
Your posts are moderated
Related Questions
What is fixism? Fixism is the theory about the diversity of life on earth that affirms that the current existent species were identical to species of the past and came out alre

Q. What do you mean by Binomial nomenclature? Binomial nomenclature is the naming of the individual entity and the group so produced through classification, according to the in

Q. What are the procedures of the photochemical stage of the photosynthesis process? Photolysis of water, with liberation of molecular photophosphorylation and oxygen of ADP, w

Debate over ethics of using gene therapy for treating human beings started since the discovery of recombinant DNA technology. The mere fact that it involves the alteration of DNA w

Give ditail account on regernation in invertebrates and vertabrites

Pyramid of Numbers - Ecological Pyramids A graphic representation of the total number of individuals of different species belonging to each trophic level in an ecosystem is kn

Q. Explain Surlyn film? Surlyn films: Surlyn (SU) is a versatile film which is sometimes favoured over polyethylene due to some unique properties such as excellent moisture b

Discuss mental nerve, its anatomic variation and surgical importance. Mental nerve, branch of inferior alveolar nerve is a very important landmark during osteotomy procedures.

Q. Direct use values of biodiversity? Direct use values are for those goods that are ensured directly e.g. food and timber. Maintaining a wide range of components of biological

Avian encephalomyelitis This is an acute infectious disease of birds (3 weeks old), which is caused by a member of the genus Enterovirus in the family Picornaviridae. Epid