Question

Read the following statements and identify whether they are true (T) or false (F):
(i) According to natural selection, variations that are heritable and make resource utilisation better for few will enable only those to reproduce and leave more progeny.
(ii) Based on observation made during sea voyage on H.M.S. Beagle, Darwin concluded that existing life forms share similarities only among themselves, and not with life forms that existed millions of years ago.
(iii) According to Darwin, fitness refers ultimately and only to reproductive fitness.
(iv) The geological history of earth does not correlate with the biological history of earth.

• A. (i – T), (ii – T), (iii – F), (iv – F)
• B. (i – T), (ii – F), (iii – T), (iv – F)
• C. (i – F), (ii – T), (iii – F), (iv – T)
• D. (i – T), (ii – T), (iii – T), (iv – F)

Answer 1

Answer: (B)

Darwinism: Given by English naturalist Charles Darwin (1809 -1882) in his book – On the Origin of Species by means of natural selection (1859). He traveled to Galapagos Islands between 1831 -1836 by the ship named HMS Beagle. The theory given by Charles Darwin - Theory of Natural Selection puts forward the following postulates :
All living organisms possess enormous reproductive potential.
Struggle for existence: Limitation of food and shelter leads to a struggle for existence which is of following types – A. Intraspecific struggle (the most acute type of struggle), B. Interspecific struggle (Most potent force for evolution), and C. Extra specific struggle: It is the struggle between the organisms and their environment in the form of drought, flood, cold, rain, heat, etc.
Variations and heredity: According to Darwin, every population has built-in variations in characteristics. No two individuals are alike. Only continuous and useful variations are the raw material of evolution.
Natural selection (or Survival of the fittest): Only those organisms will survive which possess the most useful variations. This has been called 'Natural selection' by Darwin and 'Survival of fittest' by Herbert Spencer. According to Darwin, fitness refers ultimately and only to Reproductive fitness.
Favorable variations accumulate over generations to ultimately result in speciation.
The study shows that various life forms have evolved, and certain life forms are restricted to certain geological periods. New forms have arisen at different times in the history of earth i.e. evolution has taken place. Usually, fossils found in older sedimentary rocks are of simpler types, while those found in newer rocks are of complex type. With the help of fossils, we can study the evolutionary pedigree of animals like horses, elephants, and man.