Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Members belonging to different species refrain from mating because of the behavioural differences between them. Such behavioural differences usually centre around specific courtship patterns which the species have evolved. The behaviour patterns are more conspicuous in animals rather than in plants. And among animals, once again, the courtship behaviour is more pronounced among terrestrial and fresh water organisms than in marine forms. Mayr points out that in those forms where there is an elaborate courtship behaviour the interspecific hybrids are rare. Closely related species that do not have pair-binding courtship rituals do commonly give rise to hybrids. Mayr is of the opinion that in species where there is a courtship behaviour pattern, the "engagement" may be broken if the pairs do not belong to the same species, A detailed study of the courtship behaviour of six species of Drosophila showed that courtship and mating could be divided into six phases. If there is incompatibility at any one of these six phases, the potential mates break off and the courtship is discontinued. Under laboratory conditions, the interspecific crosses have not been successful and the courtship was terminated even in the first stage. What is more interesting here is that even to a trained observer differences in courtship behaviour exhibited by different species may appear to be trivial and insignificant. But the species recbgnise the specific signals and respond suitably. In certain other forms differences in courtship behaviour between species could be very pronounced, The courtship dances of the different species of Uca (shore crab) could be recognised from a distance. This is also true of mating dances of salamanders, turtles and birds.
Q. Show types of hiatus hernia? Depending on the extent of herniation and placement of stomach, it could be of two types: 1, Para Oesophageal Hernia (oesophagus is in normal
An enhance in parasympathetic discharge to the heart leads to A. An enhance in the conductance of F-channels in SA node cells. B. An enhance in the conductance of potassium
Is fecundation in amphibians external or internal? In this aspect are amphibians evolutionarily proximal to fishes or to reptiles? In the majority of the amphibian species fec
Define Modes or Techniques for Chromatographic Separation In practice, chromatographic separation may take one of these modes or techniques: Paper chromatography (in w
what is the function of dna primer
The Eukaryotic transcription is more difficult than prokaryotic transcription. For example, in eukaryotes the genetic material DNA and therefore transcription is basically localize
Q. List the functions of insulin? a) Insulin controls the level of the sugar (glucose) in the blood. b) Insulin permits cells to use sugar (glucose) for energy. Cells cannot
Q. How do hormonal tests to detect pregnancy work? Laboratory tests to detect pregnancy commonly test for human chorionic gonadotropin (HCG) concentration in urine or blood sam
Define Thin Layer Chromatography? This is an improvement over paper chromatography and uses thin layers of slurried absorbents like silica gel, alumina, cellulose, Kieselguhr,
What is an antigen? Antigen is any substance, particle or infectious agent known as foreign to the body. The contact of the antigen with the body promotes a defense reaction ag
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd