In biology the egg is the zygote of the animals. It is a cell that is formed after fusion of the nucleus of the ovum with the sperm nucleus by karyogamy. During fertilization of an egg by a sperm, the chromosomes of the male parent does not merge or blend with the chromosomes of the female parent, but coexist in the fertilized egg.
Mammalian eggs are among the smallest in the animal kingdom. The ostrich egg is the largest egg currently known weighing 1.5 kg (3.3 lb).
The first discovery of a dinosaur eggshell occurred in 1859 by a French priest, Father Pouech. The best and most abundant information on dinosaur reproduction comes from eggs and their overall arrangement relative to other eggs.
To biology, the development of a whole body from an egg is still a mystery. Eldredge writes:
|“||"And that remains perhaps the greatest amazing, and as yet incompletely solved mystery of all biology: How can a single fertilized egg...develop into such a complex, yet finely integrated, system of two hundred different kind of cells, each performing a specialized function as constituents of different sort of issues and organs? There's no problem multiplying through cell division, but we are not gigantic, billion-celled fertilized eggs."||”|
Although the process of embryonic development has been studied, it is not fully understood how cells differentiate.
Ostriches lay their eggs in nests community in an interesting way. The dominant male and the major hen are the ones that play a role in the process of incubation and strangely, the major hen, it seems, is able to tell which eggs are hers and able to rearrange it so that the eggs are always covered. However in a study by Bertram on 57 ostrich nests he observed that major hens pushed out of the center of the nest eggs of some minor hens but in one of the five nests he observed that one of the eggs pushed out of the center of the nest was an egg of the major hen itself.
There are many formats of unconventional nests among birds. In the Galapagos Islands, for example, the blue-footed booby, a kind of sulid establishes a ring of guano around a place, marking her "nest".
There are also birds that act as parasites. The European Cuckoo (Cuculus canorus) is a bird that instead of building a nest, lays its eggs in the nests of other birds.
References in the Bible
The word for egg (Hebrew: ביצ, Bêtsâ) means whiteness and appears in the Bible only in the plural form (ביצים, Bêtsîm).Eggs are mentioned in some books of the Bible. Deuteronomy 22:6 prohibits taking up a bird sitting on the young or on the eggs. Isaiah 34:15 mentions an owl making its nest and putting their eggs. Isaiah 59:5 mentions cockatrice eggs. Job 39:14 mentions ostrich eggs. According to Judaism, eggs are kosher if they are from permitted birds and have no blood in them. These eggs are pointed at one end.
- Mayr, Ernst (2001). What Evolution Is. New York: Basic Books. p. 92. ISBN 0-465-04425-5.
- Strachan, Tom; Read, Andrew P (2011). Human Molecular Genetics (4th ed.). New York: Garland Science. p. 148. ISBN 978-0-8153-4149-9.
- Paul, Gregory S, ed. (2000). The Scientific American Book of Dinosaurs: The Best Minds in Paleontology Create a Portrait of the Prehistoric Era. New York: Byron Preiss Visual Publications/St. Martins Griffin. p. 283. ISBN 0-312-31008-0.
- Eldredge, Niles (2004). Why We Do It: Rethinking Sex and the Selfish Gene. New York: W. W. Norton. p. 102. ISBN 0-393-32695-0.
- Bertram, Brian C. R (1992). The Ostrich Communal Nesting System. Princeton, New Jersey: Princeton University Press. p. 110-114. ISBN 0-691-08785-7.
- Gould, Stephen Jay (1983). Hen's Teeth and Horse's Toes. New York: W. W. Norton. p. 48. ISBN 0-393-30200-8.
- Futuyma, Douglas J. (2005). Evolution. Sunderland, Massachusetts: Sinauer Associates, Inc. p. 436. ISBN 978-0-87893-187-3.
- Douglas, J.D.; Tenney, Merril C, ed. (1987). The New International Dictionary of the Bible. Grand Rapids, Michigan: Zondervan Publishing House. p. 293. ISBN 0-310-33190-0.
- Unger, Merrill F (1988). Harrison, R. K.. ed. The New Unger´s Bible Dictionary. Chicago: Moody Press. p. 334. ISBN 0-8024-9037-9.
- "Kosher Eggs". Chabad.org. Chabad-Lubavitch Media Center.
- Unterman, Alan (1997). Dictionary of Jewish Lore & Legend. Thames and Hudson. p. 199. ISBN 978-0500279847.
- Chickscope Day 1: The Journey Begins