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. How sex occurs in bacteria? Occurrence of sex in bacteria was first described by Edward Tatum and Joshua Lederberg in 1946 (Nature, volume 158, page 558) who were studying m
Manifestations of Hypertension • Renal Failure • Left Ventricular Failure • Myocardial Infarction • Cerebral Haemorrhage
what is phylum protozoa
Define the working of pH Meter? The pH of a solution, we know, measures the degree of acidity or alkalinity relative to the ionization of water sample. A pH meter is a sophisti
what are the organs of respiration in lower forms of animals?
Q. 2-Dimensional Echocardiography constrictive pericarditis? Thickened pericardium can be detected. In about a third of patients there will be associated some degree of perica
Bronchial asthma: Bronchial asthma is characterised by bouts of dyspnoea as a result of temporary narrowing of bronchi due to bronchial spasm, mucosal edema and thick secret
what three connective tissues are liquid
What are sieve tubes suited for translocation of food? a.bordered pits b.no end walls c.bordered lumen and perforated cross walls D.no protoplasm
EYE HISTOR Y - Steva n described it first. Study of eye is ophthalmology. Instrument used to examine interior of eye is ophthalmoscop e . SHAP E - More o
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