Question

Which one of the following sequences was proposed by Darwin and Wallace for organic evolution?
(a)Overproduction, variations, constancy of population size, natural selection.
(b) Variations, constancy of population size, overproduction, natural selection.
(c)Overproduction, constancy of population size, variations, natural selection.
(d)Variations, natural selection, overproduction, constancy of population size.

Answer 1

Hint: For the origin of new species through evolution there should be a large sample of variability present along with the struggle for existence because of which the organism with the best characteristics suited for the environment is selected.

Complete answer:
The sequence proposed by Darwin and Wallace for organic evolution is overproduction, variations, the constancy of population size, natural selection. First, the species produces an enormous number of offspring which contains variation. Then the extra population is eliminated because not all the offspring can survive the interspecific, intraspecific, extra specific competition. This results in a struggle for existence.
This struggle for existence and heritable variations from parents to progeny results in the survival of the fittest or natural selection.
The survival of the fittest results in a phenotype picked which is best suited for the environment. But with time even the environment changes, causing the species to change accordingly as well. After many years this changing environment along with the species changing to fit in it results in the origin of a new species.
So, the correct option is ‘Overproduction, variations, the constancy of population size, natural selection.’

Note: -Charles Darwin traveled by H.M.S Beagle to South America, South Africa, Australia, and Galapagos Island.
-Alfred Wallace traveled to South-Eastern Asia, South America, and the Malay Archipelago(Indonesia).
-The Theory of Natural selection proposed jointly by Charles Darwin and Alfred Wallace was published in the book “On the origin of species by the means of Natural Selection”.