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.
Describe Class Ophiuroidea in general way? Brittle stars have a central disc with five long, thin, flexible arms that can be detached from the body at will in times of danger.
Contra Indication : It is absolutely contra indicated if their is more than trivial aortic regurgitation. Aortic aneurysm and severe aorto iliac disease are also contra indicatio
What is cell theory? Cell theory declares that the cell is the constituent unit of living beings. Before the discovery of the cell, it was not identified that living beings
A fruit fly has four pairs of chromosomes in its cells. At meiosis, how many dissimilar combinations of maternal and paternal chromosomes are possible in the gametes? In gamet
Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4
Explain Energy requirement during tuberculosis Energy : The criteria to establish the energy intake is the body weight status coupled with the rise in body temperature. Con
Define Recommended Dietary Allowance for pyridoxine (RDA)? Average requirements for pyridoxine vary with age, sex and physiological conditions such as protein status, pregnan
Q. What are cerebrospinal and meninges fluid? Meninges are the membranes that protect and the enclose central nervous system (CNS). Cerebrospinal fluid is the fluid that separa
Select all that are true: Plants do not have mitochondria, they have chloroplasts to convert the sun's energy into chemical energy via photosynthesis and do not need to make ATP us
What is inheritence and what is the relation between mendel and darwin?
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