Evolution Test 2

• Industrial melanism is an adaptation where the moths living in industrial areas develop melanin pigments to match their body to the soot covered surroundings.
• In this case, moths with dark coloured will be selected by nature and hence they will be reproductively successful as compared to moths of light colour. Hence it is an example of protective colouration.

► Geographical isolation is the physical separation of two populations by geographical barriers. This occurs through adaptive radiation and allopatric speciation.

► Reproductive isolation is the separation of two populations of the same species, preventing interbreeding and production of fertile offspring.

The peppered moth Biston betularia is also a model of parallel evolution in the incidence of melanism in the British form (f. carbonaria) and the American form (f. swettaria) as they are indistinguishable in appearance. Genetic analysis indicates that both phenotypes are inherited as autosomal dominants.

• The population may sometimes be reduced to low numbers by predation, diseases, adverse period of climatic changes. Earthquakes, floods, etc.
• The few surviving individuals may constitute a random genetic sample of the original population. The resultant alterations and loss of genetic variability are known as the bottleneck effect.

The Hardy-Weinberg principle states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences. It operates in the absence of mutation, natural selection and recombination