Ethological isolation, Biology

Assignment Help:

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.


Related Discussions:- Ethological isolation

Determine the digestion of carbohydrates, How does the pancreatic juice res...

How does the pancreatic juice resume the digestion of carbohydrates? What is the involved enzyme? Carbohydrate digestion starts with the action of the salivary amylase (ptyalin

Which of the following structures in a vertebrate, Which of the following s...

Which of the following structures in a vertebrate with a four-chambered heart would have blood with the highest oxygen concentration? And why? A. Arteriole end of a capillary B. Ri

Describe the supra cardiac type of tapvc, Describe the Supra Cardiac Type o...

Describe the Supra Cardiac Type of TAPVC ? After connecting the baby to cnrdiopulmonary bypass, the common pulmonary venous channel is dissected. This lies behind the left atr

Define about aliphatic alcohols - non glyceride fractions, Define about Ali...

Define about Aliphatic alcohols - Non Glyceride Fractions? These are water-insoluble, with their content varying from 0.5-7% of the unsaponifiable matter. Rice bran oil contain

Describe the term - intellectual processes scales, Describe the term - Inte...

Describe the term - Intellectual Processes scales The 269 items are divided into 11 content scales, each of which may be administered individually. Since these scales contain v

Explain the term health, Explain the term 'health' Mention any two ways of ...

Explain the term 'health' Mention any two ways of maintaining it. Why does a doctor administer tetanus antitoxin and not a tetanus vaccine to a child Injured in a roadside acci

Explain caspofungin, Explain Caspofungin It is available only for intra...

Explain Caspofungin It is available only for intravenous administration and is FDA-approved for treatment of esophageal candidiasis, candidemia, and intra-abdominal abscesses,

What is active transport--secretion, What is Active Transport--Secretion ...

What is Active Transport--Secretion This method is now a well accepted process of aqueous formation. The rate of aqueous humour formation depends on the rate of active solute

Climax stage - hydrarch, Climax Stage - Hydrarch A variety of trees in...

Climax Stage - Hydrarch A variety of trees invade the woodland community which soon develop into the climax community. The nature of the climax is dependent upon the climate o

What are differentiations of the cell membrane, In some types of cells, the...

In some types of cells, the cell membrane present differentiations that are essential for the specific functions of the cells. The major differentiations are the microvilli and the

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

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!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd