Explain the role of light and the duration of day in the ecosystem?

The intensity, quality and the duration of light play an important role for the survival of organism. The organisms have photoreceptors. The light may lead to many processes. The photosynthesis is performed by the autotrophs. It provides food to plants as well as animals. Light is essential for this process. Light intensity is more at equator. So, the tropical forests have greater productivity as compared with the other forests. Almost no vegetation appears in the tundra region. The differentiation of tissues in plants requires light. It also affects the growth. The higher intensity of light produces internodes and leaves. These are smaller in size. The mechanical tissues and flowers are more in number. They have smaller cells. The lower intensity of light produces internodes and leaves which are larger in size. The mechanical tissues and flowers are few in number. The cells are large in size. The strong intensity of light produces the light yellow and red pigmentation. The moderate intensity of light produces the bright green pigmentation. The change in skin color occurs due to the change in intensity of light. It occurs in the animals as well as human beings. The frog and wall lizard look light in color when they appear in bright sunlight. In the sunset they appear dark in color. There are few animals which show the seasonal changes. Some of the species of hare develop a white color in the season of autumn. The animals are active in the different parts of day. They become active during night, early morning and the evening. These processes are referred as nocturnal, auroral and vesperal phenomena. The nocturnal types include the moths, owl and bats. The auroral type includes the rabbit. There are diurnal animals which are active during the day and include the sparrows, crow, pigeon and cattle. Some of the plants show movement in response to the unidirectional light. The surface of water shows motile algae. These occur in the dim light and in deep areas. In the few plants the folding of leaves occur at the different time of day. They may occur in the night in case of oxalis and may occur at midday in some grasses and legumes. The length of day plays an important role in the migration of bird, leaf fall, and dormancy of bud and the formation of new leaves. The decrease in day length leads to the leaf fall, bud dormancy and migration of birds. The flowering is controlled by the period of length and darkness. It occurs mainly in the angiosperms. The flowering plants are divided into different types. They depend on the day length. They can be short day or long day. The short day includes the dahlia and xanthium. The long day plant includes the radish and spinach. The day neutral plant includes the tomato. The animal breeding is affected by the season and the photoperiodicity. They depend on the length of day. They can be short day, long day or neutral. The short day animal includes the sheep and goats. The long day animal includes the ferrets and turkeys. The neutral animal includes guinea pigs and squirrels.