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Definition [ edit ] The word pedigree is a corruption of the Anglo-Norman French pé de grue or "crane's foot", either because the typical lines and split lines (each split leading to different offspring of the one parent line) resemble the thin leg and foot of a crane [ 3 ] or because such a mark was used to denote succession in pedigree charts.
Pregnant male seahorse. Male pregnancy is the incubation of one or more embryos or fetuses by organisms of the male sex in some species. Most species that reproduce by sexual reproduction are heterogamous—females producing larger gametes and males producing smaller gametes ().
Diagram of stages of embryo development to a larval and adult stage. 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]
Pregnant scorpion. In viviparous animals, the embryo develops inside the body of the mother, as opposed to outside in an egg . The mother then gives live birth. The less developed form of viviparity is called ovoviviparity, in which the mother carries embryos inside eggs. Most vipers exhibit ovoviviparity. [15]
Drawing of the head of a four-week-old human embryo. From Gray's Anatomy.. Embryo drawing is the illustration of embryos in their developmental sequence.In plants and animals, an embryo develops from a zygote, the single cell that results when an egg and sperm fuse during fertilization.
Human reproduction naturally takes place as internal fertilization by sexual intercourse. During this process, the man inserts his erect penis into the woman's vagina and then either partner initiates rhythmic pelvic thrusts until the man achieves orgasm , which leads to ejaculation of semen containing sperm into the vaginal canal.
A pregnant lioness. In mammals, pregnancy is the period of reproduction during which a female carries one or more live offspring from implantation in the uterus through gestation. It begins when a fertilized zygote implants in the female's uterus, and ends once it leaves the uterus.
During the Renaissance, artist and scientist Leonardo da Vinci famously sketched his observations from human dissections, as well as his studies of plants and the flight of birds. In the mid-16th century, the physician Andreas Vesalius compiled and published the De humani corporis fabrica , a collection of textbooks on human anatomy superior to ...