NEET Biology Evolution MCQs Set 05

Answer: (c) Weismann - Theory of continuity of germplasm

Explanation:
1. de Vries proposed the mutation theory, Darwin proposed natural selection and pangenesis, and Lamarck proposed inheritance of acquired characters.
2. Weismann proposed the theory of continuity of germplasm, so (c) is correctly matched.

Teacher's Note:
1. Weismann cut off the tails of mice for many generations to disprove Lamarckism.
2. Pasteur disproved spontaneous generation.

Answer: (c) Continental drift

Explanation:
1. Australia drifted away from the other continents and became isolated.
2. Isolated, the marsupials could not be replaced by placental mammals, so they survived and underwent adaptive radiation.

Teacher's Note:
1. Placental mammals in the other continents out-competed the marsupials.
2. Continental drift acted as a geographical barrier.

Answer: (a) Divergent evolution

Explanation:
1. Homologous structures have a similar anatomical plan but different functions.
2. They arise from a common ancestor by adaptation to different environments, which is divergent evolution.

Teacher's Note:
1. Analogous structures result from convergent evolution.
2. The forelimbs of whales, bats, cheetahs and humans are homologous.

Answer: (a) Archaezoic

Explanation:
1. Life started in the Archaean (Archaezoic) era with the formation of the first prokaryotic cells.
2. Phanerozoic is the age of complex multicellular life, and the Proterozoic saw the rise of eukaryotes and oxygen.

Teacher's Note:
1. Cyanobacteria appeared in this time and began oxygenating the atmosphere.
2. Phanerozoic includes the Palaeozoic, Mesozoic and Cenozoic eras.

Answer: (d) Four

Explanation:
1. The vestigial organs in the list are the coccyx, nictitating membrane, muscles of the ear pinna and the vermiform appendix.
2. A tail in a newborn and a cervical fistula are atavistic features, and the second molar is a functional tooth (the third molar is the reduced one).
3. So four are vestigial.

Teacher's Note:
1. Vestigial organs are reduced and non-functional in the present organism.
2. Atavism is the reappearance of an ancestral character.

Answer: (d) Convergent evolution

Explanation:
1. In Australia, marsupials adapted to different habitats and evolved to look like placental mammals of other continents.
2. When several adaptive radiations occur in one isolated area and produce similar-looking forms, it is called convergent evolution.

Teacher's Note:
1. Convergent evolution gives analogous structures.
2. The Tasmanian wolf resembles the true wolf, but is a marsupial.

Answer: (c) \(Homo\ sapiens\ sapiens\)

Explanation:
1. Agriculture started about 10,000 years ago, in the Neolithic period, with the arrival of modern man.
2. The modern human is \(Homo\ sapiens\ sapiens\), and the earlier forms did not practise agriculture.

Teacher's Note:
1. Neanderthals buried their dead but did not farm.
2. Cave art is associated with Cro-Magnon man.

Answer: (b) Palaeozoic - Mesozoic - Cenozoic

Explanation:
1. The Phanerozoic eon is divided from oldest to youngest into the Palaeozoic, Mesozoic and Cenozoic eras.
2. The correct sequence is therefore Palaeozoic, Mesozoic, Cenozoic.

Teacher's Note:
1. Reptiles dominated the Mesozoic era.
2. Mammals and flowering plants dominate the Cenozoic era.

Answer: (d) Malay Archipelago

Explanation:
1. Alfred Russel Wallace worked in the Malay Archipelago.
2. Darwin visited the Galapagos islands during the voyage of the Beagle.

Teacher's Note:
1. Both Darwin and Wallace independently arrived at natural selection.
2. Wallace was influenced by Malthus as well.

Answer: (b) Evolution of different species from a common ancestor

Explanation:
1. In adaptive radiation, different species evolve in different habitats from a common ancestor.
2. It is a form of divergent evolution, so it is not convergent evolution or simple migration.

Teacher's Note:
1. Divergent evolution produces homologous structures.
2. The beak variation in Darwin's finches is a result.

Answer: (a) Darwin

Explanation:
1. Charles Darwin proposed the theory of natural selection in 'On the Origin of Species' (1859).
2. Lamarck proposed the inheritance of acquired characters, Malthus wrote on population, and de Vries proposed the mutation theory.

Teacher's Note:
1. Malthus's essay on population influenced Darwin.
2. Darwin's two key concepts are branching descent and natural selection.

Answer: (b) Saltation

Explanation:
1. De Vries called single-step large mutations saltation.
2. He believed that such mutations cause speciation, as opposed to the small gradual variations of Darwin.

Teacher's Note:
1. Mutation theory is by Hugo de Vries, based on evening primrose.
2. Darwinian variations are small and directional.

Answer: (b) variations may or may not be inherited from parents to offspring through genes

Explanation:
1. Darwin did not know about genes and did not explain how variations are inherited.
2. His theory covers variation within species, over-production of offspring and survival of the fittest.

Teacher's Note:
1. The gene concept came later from Mendel's work.
2. Modern synthetic theory adds genetics to Darwinism.

Answer: (c) \(Australopithecus\)

Explanation:
1. Australopithecus, the early hominid of East Africa, walked upright on two legs.
2. Java man (Homo erectus) and Peking man came later, and Cro-Magnon man is modern \(Homo\ sapiens\).

Teacher's Note:
1. Australopithecus had a small brain of about 400 to 500 cc.
2. The first human-like brain size appeared in Homo habilis.

Answer: (b) It is directional natural selection where one of the two extremes is selected

Explanation:
1. After industrialisation the dark moths had better camouflage, so the population shifted towards the dark extreme.
2. Selection of one extreme and a shift of the mean is directional selection, whereas stabilising selection favours the median.

Teacher's Note:
1. Stabilising selection removes both extremes.
2. Disruptive selection favours both extremes.

Answer: (a) \(Australopithecus\)

Explanation:
1. 'Lucy' is a nearly complete fossil skeleton found in Ethiopia in 1974.
2. It belongs to \(Australopithecus\ afarensis\).

Teacher's Note:
1. Lucy lived about 3.2 million years ago and walked upright.
2. Pithecanthropus is the old name of Java man.

Answer: (a) White winged

Explanation:
1. Before industrialisation, tree trunks were covered with white lichens, so white winged moths were camouflaged.
2. They escaped predation and were more numerous than the dark winged moths.

Teacher's Note:
1. After industrialisation, soot darkened the trees and the dark moths survived better.
2. This is the classic example of natural selection.

Answer: (d) The earth is about 4000 years old

Explanation:
1. The earth is about 4.5 billion years old, not 4000 years, so (d) is incorrect.
2. The early earth had no atmosphere, and life appeared about 500 million years after the formation of the earth, with the first non-cellular forms about 3 billion years back.

Teacher's Note:
1. Radiometric dating gives the age of the earth.
2. The first cellular life appeared about 2000 million years ago.

Answer: (b) Statements (a), (d)

Explanation:
1. Neanderthals had a brain size of about 1400 cc, so (a) is incorrect.
2. They lived in the near east and central Asia 100,000 to 40,000 years back and used hides to protect their body, so (b) and (c) are correct.
3. Cave colour painting is associated with Cro-Magnon man, so (d) is incorrect.

Teacher's Note:
1. Neanderthals buried their dead.
2. Cro-Magnon man made cave paintings.

Answer: (d) Equus

Explanation:
1. The horse evolved through Eohippus, Mesohippus, Merychippus and Pliohippus.
2. The living horse is Equus.

Teacher's Note:
1. Horse evolution shows an increase in size and a reduction in the number of toes.
2. Equus has a single toe, the middle one, with a hoof.

Answer: (a) \(\mathit{Australopithecus} \rightarrow \mathit{Homo\ habilis} \rightarrow \mathit{Homo\ erectus} \rightarrow \mathit{Homo\ sapiens}\)

Explanation:
1. Australopithecus lived about 3-4 million years ago, Homo habilis about 2 million years ago, Homo erectus about 1.5 million years ago, and Homo sapiens appeared about 75,000-100,000 years ago.
2. So the order is Australopithecus, Homo habilis, Homo erectus, Homo sapiens.

Teacher's Note:
1. Brain size increases along this series, from about 400 cc to 1400 cc.
2. Homo habilis was the first member of the genus Homo.