Origin and Evolution of Life
Short Questions and Answers
One Mark Questions with Answers
1. Which of these are considered most essential in the origin of life?
(b) nucleic acid
Answer: (b) nucleic acid
2. The theory which explains the origin of life and is based upon experiments
(a) chemical theory
Answer: (a) chemical theory
3. Galapagos Islands are associated with the name of
Answer: (c) Darwin
4. A connecting link between reptiles and birds is
Answer: (c) Archaeopteryx
5. In phylogeny of horse, earliest fossil form is
Answer: (a) Eohippus
6. Wings of pigeon, bat and mosquito exhibit the phenomenon called
(a) convergent evolution
(b) divergent evolution
(d) all of these
Answer: (a) convergent evolution
7. The golden age of reptiles is
Answer: (c) Mesozoic
8. Adaptive similarities in different animals living in same habitat is called
(a) retrogressive evolution
(b) parallel evolution
(c) adaptive radiation
(d) convergent evolution
Answer: (d) convergent evolution
9. Among the following, a structure, which is not vestigial is
(a) wisdom teeth
(b) plica semilunaris
(c) vermiform appendix
Answer: (d) nails
10. Darwin finches show one of the following aspects of evolution
(a) biogeographic evidence
(b) industrial melanism
(c) biochemical evidence
(d) embryological evidence
Answer: (a) biogeographic evidence
11. The modern bird rise in
Answer: (c) Mesozoic
12. Homologous organs indicates the
(a) convergent evolution
(b) parallel evolution
(c) common descendant
(d) natural selection
Answer: (c) common descendant
Two Marks Questions with Answers
1. Give an account of coacervate formation after the large organic molecules synthesizers on earth?
Answer: The large organic molecules which are synthesized a vertically on primitive or later came together and due to intermolecular attraction the formulas for idle aggregate Sach water bound aggregates have been named microspheres type Sydney fox and were named coacervate bioperine
2. How could chemoautotrophs evolve?
Answer: As the environment over the earth became cooler, formation of new organic molecules stopped. The already present organic materials decreased due to continued withdrawal by chemoheterotrophs. Before the organic materials disappeared in the sea broth, new modes of nutrition developed. One of them was chemosynthesis. The organisms performing chemosynthesis are called chemoautotrophs.
3.Which property of water makes the existence of life possible under the antarctic sheet of ice?
Answer: The frozen water floats as a sheet of ice over the surface and protects the underlying water as well as living organisms from freezing. It is because of this reason that aquatic life is present even below the antarctic sheet of ice.
4. Why aquatic birds have reduced wings?
Answer: Aquatic birds like ducks have been evolved from the terrestrial ancestors. Since they had to go to water due to lack of food etc, some structures like web between the toes developed in them, so that they could live in water easily. The wings were not used for flying as they were not needed and later on they got reduced.
5. How migration of some organisms cause variations in offspring?
Answer: Sometimes two populations of a species which were separated, come to close due to migration, the genes of two populations in termingle through breeding and result variations in the offspring.
6. Why flat fish has both its eyes on one side?
Answer: They are flat and bear both the eyes on one side and live at the bottom of the water. During the embryonic stage their eyes are present laterally, one eye on either side. The body of these fishes is not flat at this stage but later on both the eyes are shifted to one side and the body becomes flat to withstand the pressure of water.
Three Mark Questions with Answers
1. Differentiate between Darwinism and Neo darwinism
Answer: Darwinism is original theory given by Charles Darwin to explain the origin of new species while Neo Darwinism is a modification of the original theory of Darwin to remove its shortcomings. According to Darwinism theory accumulation of continuous variations causes change in individuals to form new species while in Neo Darwinism instead of continuous variations mutations are believed to help form new species. Darwinism believes in the selection of individuals on the basis of accumulation of variations whereas in Neo Darwinism variations accumulate in the gene pool and not in the individuals. Darwinism does not believe in isolation while Neo Darwinism incorporates isolation as an essential component of evolution. Darwinism can explain the origin of new characters while Neo darwinism theory cannot explain the origin of new characters. Darwinism cannot explain the persistence of certain forms in the unchanged condition while Neo darwinism theory can explain the occurrence of unchanged forms over millions of years.
2. Differentiate between Neo Darwinism and Neo Lamarckism.
Answer: Neo Darwinism theory explains that the number of organisms of different species remain the same despite their high biotic potential and ability to increased by geometrical ratio while Neo Lamarckism is silent about high biotic potential and geometrical increase in population.
Neo Darwinism stresses the role of struggle for existence and natural selection in face of limited resources while Neo Lamarckism theory does not touch these aspects of evolutionary forces. Neo Darwinism explains the role of variations, their origin and accumulation in the formation of new species while Neo lamarckism theory consideres that the change in environment produces modifications directly due to its effect on germ cells or rarely indirectly through somatic cells.
3. Differentiate between allopatric speciation and sympatric speciation.
Answer: Allopatric speciation occurs in a spatially isolated population while sympatric speciation occurs from a segment with in a population. In allopatric speciation the barrier is physical while in sympatric speciation the barrier is ecological and genetic. In allopatric speciation there are chances of breakdown of isolating mechanism while in sympatric speciation chances of breakdown of isolating mechanism are rare. Speciation is slow in allopatric speciation while speciation is rapid in sympatric speciation.
4. Mention the three different types of struggle for existence.
Answer: Intraspecific struggle- It is the struggle between the individuals of the same species because their requirements like food, shelter, breeding places, etc are similar. Many human wars are the examples of intraspecific struggle. Cannibalism (eating the individual of its own species) is another example of this type of struggle.
Interspecific struggle- It is the struggle between the members of different species. This struggle is normally for food and shelter, for example, a fox hunts out a rabbit while the fox is preyed upon by a tiger.
Environmental struggle- It is the struggle between the organisms and the environmental factors such as drought, heavy rains, extreme heat or cold etc. Thus, climate and other natural factor also help in restricting the number of individuals of particular species.