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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.
If three different traits are controlled by the unlinked genes A, B, and C, and each has multiple alleles so that A has 4 alleles, B has 6 alleles and C has 2 alleles, how many dif
Obturator - Ovule An obturator is an outgrowth of the placenta or funicle or integument or style near the micropyle. It is presumed to guide the pollen tube to the micropyle.
FATS ( = True Fats, Triglycerides, Neutral Fats) They are esters of fatty acids and 3-carbon trihydric alcohol glycerol (= glycerine). T rue fat is also called trig
Certain conditions such as excessive alcohol consumption can increase the ratio of NADH/NAD+ in the mitochondria. This will directly inhibit which of the following enzymes? -cit
Write about embryonic stem cell invitro methord in which transgenic animal were generated and efficient show how homologous recombination happening?
Dissolved oxygen - Aquatic Habitats Oxygen in the terrestrial ecosystems occurs in the atmosphere along with other gases in a certain fixed concentration however, in aquatic e
Define nutrient requirements and principles of meal planning? In this , we started our discussion with the school age and its characteristics. We learnt about the physical grow
Please answer the following three questions on Sequence Z: Metadata The GO Ontology is a very widely-used resource in the bioinformatics community as a tool to annotate
how does the digestive system of an arthropod operate
What is Physical activity ratio? Physical activity ratio (PAR): The energy cost of an activity per unit of time (usually a minute or an hour) expressed as a multiple of BMR. It
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