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A diagram of a bird egg. Eggs of various birds, labelled (Trinity College Zoological Museum, Dublin) Bird eggs are laid by the females and range in quantity from one (as in condors) to up to seventeen (the grey partridge). Clutch size may vary latitudinally within a species. Some birds lay eggs even when the eggs have not been fertilized; it is ...
Eggs of various birds, a reptile, various cartilaginous fish, a cuttlefish and various butterflies and moths. (Click on image for key) Diagram of a fertilized chicken egg in its ninth day. Membranes: allantois, chorion, amnion, and vitellus/yolk. Six commercial chicken eggs — view from the top against a white background
In developmental biology, animal embryonic development, also known as animal embryogenesis, is the developmental stage of an animal embryo. Embryonic development starts with the fertilization of an egg cell (ovum) by a sperm cell, (spermatozoon). [1] Once fertilized, the ovum becomes a single diploid cell known as a zygote.
The oviduct in vertebrates is the passageway from an ovary. In human females, this is more usually known as the fallopian tube. The eggs travel along the oviduct. These eggs will either be fertilized by spermatozoa to become a zygote, or will degenerate in the body. Normally, these are paired structures, but in birds and some cartilaginous ...
In the wild, eggs are typically laid at 3 to 5 day intervals, with records in captivity of intervals of up to 7 or 10 days. [54] [55] [56] The eggs vary from all white to white with cinnamon or brown spots and blotches. Scottish eggs averaged 75 by 59 mm (3.0 by 2.3 in) in size and weigh about 145 g (5.1 oz). [1]
Human growthand development. Human fertilization is the union of an egg and sperm, occurring primarily in the ampulla of the fallopian tube. [1] The result of this union leads to the production of a fertilized egg called a zygote, initiating embryonic development. Scientists discovered the dynamics of human fertilization in the 19th century.
The songs of birds, insects and many other animals are part of a ritual to attract potential partners of their own species. The song presents specific patterns recognizable only by members of the same species, and therefore represents a mechanism of reproductive isolation. This recording is the song of a species of cicada, recorded in New Zealand.
Ostrich egg. Ostrich eggs in a nest on a farm. The egg of the ostrich (genus Struthio) is the largest of any living bird (being exceeded in size by those of the extinct elephant bird genus Aepyornis). The shell has a long history of use by humans as a container and for decorative artwork, including beads. The eggs are not commonly eaten.