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Name: Hannah
Status: student
Age: 4-5
Location: WV
Country: N/A
Date: 12/13/2005

How is the size of an egg determined?

In chick, the egg contains all the essential nutritients & energy for the development of embryo. The egg yellow you see is the ovum (the female sex cell)that is stuffed with yolk. Yolk provides much of the energy for the development. The size of the egg among egg laying birds & reptiles are determined by the total energy required for the complete development of the embryo. The developed young one then breaks open the shell and comes out.

Among insects say for example, the eggs are too small. In such animals the eggs have energy just for partial development. The egg develops into a larva. The larva (a stage of the developing embryo) then feeds voraciously to acquire energy then develops into a pupa (cocoon) and then into a fly!

P. Kumarasamy

Often the size of the egg is determined by the size of the bird laying the egg. Ostriches have huge eggs, while robins eggs are much smaller. It also depends on how developed the baby bird will be once it comes out. If the species of bird tends to be more developed when hatching, the egg would be a bit larger than one in a species were the baby would be less developed.

Grace Fields

There's no simple answer. Small birds tend to have larger eggs in proportion to their body weight than large birds. Eggs of precocial birds, like ducks, who hatch out ready to move about and feed themselves, are proportionally larger than those of altrical birds, like robins, that are helpless when they hatch. That is because more energy has to be invested in the eggs of precocial birds, where more energy is invested in raising the nestlings of altrical birds. Nutrition also plays a role. Within a species, females who have better nutrition produce larger eggs than those with poor nutrition. I do not have any information at hand on reptile or amphibian eggs, if you have more questions ask again.

J. Elliott

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