Search results
Results from the WOW.Com Content Network
The ZW sex-determination system is a chromosomal system that determines the sex of offspring in birds, some fish and crustaceans such as the giant river prawn, some insects (including butterflies and moths), the schistosome family of flatworms, and some reptiles, e.g. majority of snakes, lacertid lizards and monitors, including Komodo dragons.
A deeper understanding of developmental biology shows that common morphology is, in fact, the product of shared genetic elements. [5] For example, although camera-like eyes are believed to have evolved independently on many separate occasions, [ 6 ] they share a common set of light-sensing proteins ( opsins ), suggesting a common point of ...
Cloning is the production of an offspring which represents the identical genes to its parent. Reproductive cloning begins with the removal of the nucleus from an egg, which holds the genetic material. [4] In order to clone an organ, a stem cell is to be produced and then utilized to clone that specific organ. [5]
In humans, barring intersex conditions causing aneuploidy and other unusual states, it is the male that is heterogametic, with XY sex chromosomes.. Haldane's rule is an observation about the early stage of speciation, formulated in 1922 by the British evolutionary biologist J. B. S. Haldane, that states that if — in a species hybrid — only one sex is inviable or sterile, that sex is more ...
[5] Family Boidae. Hybrids between Columbian boa and yellow anaconda. Genus Corallus. Hybrid between emerald tree boa and Amazon tree boa. Family Colubridae. A fertile cross between a king snake and a corn snake. One example is a cross between a California kingsnake and a corn snake called the "jungle corn snake." [6] [7] Genus Lampropeltis
The following outline is provided as an overview of and topical guide to genetics: . Genetics – science of genes, heredity, and variation in living organisms. [1] [2] Genetics deals with the molecular structure and function of genes, and gene behavior in context of a cell or organism (e.g. dominance and epigenetics), patterns of inheritance from parent to offspring, and gene distribution ...
GCSE Bitesize was launched in January 1998, covering seven subjects. For each subject, a one- or two-hour long TV programme would be broadcast overnight in the BBC Learning Zone block, and supporting material was available in books and on the BBC website. At the time, only around 9% of UK households had access to the internet at home.
Fisher's principle is an evolutionary model that explains why the sex ratio of most species that produce offspring through sexual reproduction is approximately 1:1 between males and females. A. W. F. Edwards has remarked that it is "probably the most celebrated argument in evolutionary biology". [1]