Question

describe in detail the photoperiodism in animal. add a note on biological clock.
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Answer 1

Answer:

Photoperiodism is the physiological reaction of organisms to the length of night or a dark period. It occurs in plants and animals. Photoperiodism can also be defined as the developmental responses of plants to the relative lengths of light and dark periods. They are classified under three groups according to the photoperiods: short-day plants, long-day plants, and day-neutral plants.Many flowering plants (angiosperms) use a photoreceptor protein, such as phytochrome or cryptochrome,[1] to sense seasonal changes in night length, or photoperiod, which they take as signals to flower. In a further subdivision, obligate photoperiodic plants absolutely require a long or short enough night before flowering, whereas facultative photoperiodic plants are more likely to flower under one conditionDaylength, and thus knowledge of the season of the year, is vital to many animals. A number of biological and behavioural changes are dependent on this knowledge. Together with temperature changes, photoperiod provokes changes in the color of fur and feathers, migration, entry into hibernation, sexual behaviour, and even the resizing of sexual organs.

Explanation:

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