NEET Biology Evolution MCQs Set 07

Answer: (b) Light years

Explanation:
1. A star is so far away that kilometres are impractical.
2. Astronomers use the light year, the distance light travels in one year.

Teacher's Note:
1. Light travels about 9.46 trillion km in a year.

Answer: (b) Galapagos Islands

Explanation:
1. Darwin made observations on the Galapagos Islands during the voyage of H.M.S. Beagle.
2. The varied finches and tortoises there led him to natural selection.

Teacher's Note:
1. Wallace independently worked on the Malay archipelago.

Answer: (d) None of them

Explanation:
1. After industrialisation the dark moths became more common because they were camouflaged on sooty trees.
2. The white moths became fewer but were not completely eliminated, so neither variety was wiped out.

Teacher's Note:
1. Industrial melanism shows the change in frequency of two forms, not extinction.

Answer: (a) Seed eater

Explanation:
1. The ancestral finch that reached the Galapagos was a seed eater.
2. Its descendants diversified beaks for insects, cactus and other foods by adaptive radiation.

Teacher's Note:
1. Beak shape in finches is an example of adaptive radiation.

Answer: (d) Both adaptive radiation and Australian marsupials

Explanation:
1. These marsupials arose in Australia from a single ancestral stock.
2. They therefore illustrate adaptive radiation and are all Australian marsupials.

Teacher's Note:
1. Placental mammals show similar forms elsewhere, an example of convergent evolution.

Answer: (d) All of these

Explanation:
1. Organisms with shorter life spans give rise to new forms faster.
2. Natural selection is the core of Darwin's theory and fitness depends on inherited characters.
3. So all three statements are true.

Teacher's Note:
1. Fitness means reproductive fitness, which depends on heritable traits.

Answer: (d) Both branching descent and natural selection

Explanation:
1. Darwin's theory rests on branching descent and natural selection.
2. Fitness is the result of selection, not a separate key point.

Teacher's Note:
1. Branching descent means all species arose from common ancestors by branching.

Answer: (a) 2000

Explanation:
1. Origin of the first cellular life is placed about 2000 million years ago (mya).
2. The other values are much more recent events.

Teacher's Note:
1. Life began as non-cellular chemical evolution before cells.

Answer: (d) Tyrannosaurus rex

Explanation:
1. NCERT mentions Tyrannosaurus rex as the biggest dinosaur, about 20 feet in height with huge fearsome dagger-like teeth.
2. Thecodonts were their small ancestors.

Teacher's Note:
1. Dinosaurs disappeared about 65 million years ago.

Answer: (c) Both random and directionless

Explanation:
1. Mutations occur at random and are not directed towards any adaptation.
2. They may be small or large, so (d) is wrong.

Teacher's Note:
1. Darwin's variations were small and directional, unlike mutations in the Mutation theory.

Answer: (b) Homologous organs

Explanation:
1. They have the same basic bone plan but are modified for different functions.
2. Same structure with different functions means homologous organs, showing divergent evolution.

Teacher's Note:
1. Analogous organs have different structure but similar function.

Answer: (d) Saltation

Explanation:
1. De Vries proposed the mutation theory based on his work on evening primrose.
2. He called single-step large mutations saltation, the cause of speciation.

Teacher's Note:
1. Mutation theory says evolution is discontinuous.

Answer: (a) 1953

Explanation:
1. S. L. Miller of Chicago performed the experiment in 1953.
2. He created conditions thought to exist on early Earth.

Teacher's Note:
1. Miller used CH4, NH3, H2 and water vapour at 800 degrees C with electric discharge.

Answer: (d) None of these

Explanation:
1. Miller's apparatus had a vacuum pump to remove air, electrodes for spark discharge and a condenser to cool vapour.
2. So none of these was absent.

Teacher's Note:
1. Amino acids were formed in the U-tube.

Answer: (b) Dryopithecus and Ramapithecus

Explanation:
1. Dryopithecus and Ramapithecus were hairy and walked like gorillas and chimpanzees.
2. Ramapithecus was more man-like and Dryopithecus more ape-like.

Teacher's Note:
1. Cro-Magnon man, Java man and Peking man came much later.

Answer: (c) 900 cc

Explanation:
1. Homo erectus lived about 1.5 mya and had a cranial capacity of about 900 cc.
2. Homo habilis had 650-800 cc and Neanderthal man about 1400 cc.

Teacher's Note:
1. Homo erectus probably ate meat.

Answer: (b) Continental drift

Explanation:
1. Australia separated from other continents by continental drift.
2. The isolation protected the marsupials from competition with placental mammals.

Teacher's Note:
1. Marsupials elsewhere were largely replaced by placentals.

Answer: (c) 65 million years ago

Explanation:
1. Dinosaurs became extinct about 65 million years ago.
2. 65 billion years is older than the universe.

Teacher's Note:
1. Mammals then became dominant.

Answer: (b) Lobefins

Explanation:
1. Fish with strong, fleshy fins (lobefins) could move on land.
2. They evolved into the first amphibians, ancestors of reptiles.

Teacher's Note:
1. Coelacanth is a living lobefin.

Answer: (a) Stabilising selection

Explanation:
1. Stabilising selection favours the average phenotype.
2. More individuals acquire the mean value, so the peak becomes higher and narrower.

Teacher's Note:
1. Directional selection shifts the peak, disruptive selection creates two peaks.

Answer: (b) A, B, C and D

Explanation:
1. All four are the observations Darwin used.
2. From limited resources and stable numbers he inferred a struggle for existence, and heritable variations allowed selection.

Teacher's Note:
1. Observations (A) to (D) lead to the inference of survival of the fittest.

Answer: (b) Adaptive radiation

Explanation:
1. Evolution of different species in a geographical area radiating from a point is adaptive radiation.
2. Darwin's finches are the classic example.

Teacher's Note:
1. Adaptive radiation is a type of divergent evolution.

Answer: (c) Natural selection

Explanation:
1. Dark moths were selected in polluted areas because predators could not see them.
2. This shows natural selection acting on existing variation.

Teacher's Note:
1. Frequency of dark form rose after industrialisation.

Answer: (b) Convergent evolution

Explanation:
1. Australian marsupials and placental mammals show several adaptive radiations in one area.
2. NCERT calls this convergent evolution.

Teacher's Note:
1. Similar forms evolved independently in different habitats.

Answer: (d) A, B and C

Explanation:
1. Octopus and mammalian eyes and penguin and dolphin flippers are analogous structures.
2. Sweet potato (modified root) and potato (modified stem) are also analogous, so all three are correct.

Teacher's Note:
1. Analogous structures arise by convergent evolution.

Answer: (a) Divergent evolution

Explanation:
1. Same origin with different functions is divergent evolution.
2. Homologous organs are the result.

Teacher's Note:
1. Forelimbs of vertebrates are an example.

Answer: (d) All of these

Explanation:
1. The theory of special creation has three connected ideas.
2. All of the listed statements are part of it.

Teacher's Note:
1. It was rejected after Darwin's observations.