Periodic variations in light-diurnal and seasonal, Biology

Periodic Variations in Light-Diurnal and Seasonal

We know that rotation of the earth on its axis accounts for day-to-night variations in the amount of radiations falling at a given place and seasonal variations occur due to the orbiting of the earth around the sun. Since the earth's equatorial plane is inclined to its orbit at an angle of 23o.27'. the rays of the sun do not fall vertically on all parts of the earth. From March 22nd to Sept. 22nd (AutumnaTequinox), the northpole is inclined towards the sun. So the most intense solar beam is focused on the northern hemisphere. We in the northern hemisphere, have summer season and on the northpole the sun shines for 24 hours of the day. While on South pole it is dark for six months and the southern hemisphere has winter season. The opposite situation exists on the poles from September 24 to March 20 (spring equinox) when the northern hemisphere has winter season and southern hemisphere has
summer season (Figure shown below).

1739_periodic varaitions.jpg

There is also horizontal variation in the distribution of radiation on the earth. Because the earth is nearly spherical in shape, parallel beam of incoming sunlight does not fall vertically on all parts of the earth. It strikes lower latitudes more directly than higher latitudes. Therefore, at higher latitudes the incident radiation falls obliquely on the surface, travels more through the atmosphere, and spreads over a greater area and thus is less intense than the vertical beam falling on or near the equator.

 

Posted Date: 12/10/2012 6:10:49 AM | Location : United States







Related Discussions:- Periodic variations in light-diurnal and seasonal, Assignment Help, Ask Question on Periodic variations in light-diurnal and seasonal, Get Answer, Expert's Help, Periodic variations in light-diurnal and seasonal Discussions

Write discussion on Periodic variations in light-diurnal and seasonal
Your posts are moderated
Related Questions
Q. What are the complications of chronic dyspepsia? Complications of dyspepsia are listed below: • Wright loss: Since eating most of tell provokes the symptoms, patients res

ORGNELS WITH SINGLE WALL

Q. What are some representatives of the echinoderm phylum? Starfishes, sea urchins, sea cucumbers (holothurians) and brittle stars are examples of echinoderms.

How does the photoperiodism affect the flowering of some plants? Flowering is a typical and simple to observe instance of photoperiodism. Most flowering plants flower only duri

What are the "chiasms" of homologous chromosomes seen in prophase I? Chiasms are intersections of two tracts in the form of X. The chiasms seen in prophase I are chromosome

Q. Are there differences between the male and female skeletons? Many general differences exist between female and male skeletons. Male skeleton is normally larger and heavier t

Q. Show technical aspects of the postero-anterior film? 1) Identification: Patient identification and side marker must be present. 2) Centering: The thoracic spinous pro

Overall senescence - Senescence Only the parts above the ground level i.e.  The aerial parts die whereas the underground parts survive For example, potato.

Tpes of Diarrhoea: Diarrhoea can be acute, chroniclpersistent diarrhoea and dysentery.  If an episode of diarrhoea lasts less than 14 days, it is acute diarrhoea. Acute wat

General characteristics of phylum