NEET Biology Evolution MCQs Set 09

Answer: (b) light years

Explanation:
1. A light year is the distance travelled by light in one year, used for the vast distances between stars.

Teacher's Note:
1. The universe is estimated to be about 20 billion years old in the textbook view.

Answer: (a) Big Bang theory

Explanation:
1. The Big Bang theory says the universe began from a single huge explosion of a very dense mass.

Teacher's Note:
1. Earth is believed to have formed about 4.5 billion years ago.

Answer: (d) spontaneous generation

Explanation:
1. Spontaneous generation was disproved by Louis Pasteur's careful experiments with swan-neck flasks.

Teacher's Note:
1. Pasteur showed that life comes only from pre-existing life.

Answer: (c) Louis Pasteur

Explanation:
1. Pasteur boiled broth in swan-necked flasks and showed that no life developed unless germs entered.

Teacher's Note:
1. This disproved spontaneous generation.

Answer: (b) chemical evolution

Explanation:
1. They proposed chemical evolution, the formation of diverse organic molecules from inorganic constituents, followed by the origin of life.

Teacher's Note:
1. Miller later tested the idea experimentally.

Answer: (a) CH4, H2, NH3 and water vapour

Explanation:
1. He used methane, hydrogen, ammonia and water vapour (a reducing atmosphere) and obtained amino acids.

Teacher's Note:
1. The early atmosphere lacked free oxygen.

Answer: (d) Charles Darwin

Explanation:
1. Darwin's observations, especially in the Galapagos Islands, led to his theory of natural selection.

Teacher's Note:
1. Wallace independently reached similar conclusions in the Malay Archipelago.

Answer: (c) reproductive fitness

Explanation:
1. Individuals that leave more offspring are the fittest in Darwin's sense.

Teacher's Note:
1. Survival matters only if it leads to more offspring.

Answer: (b) natural selection

Explanation:
1. Variations are inherited and those best suited to the environment are selected, leaving more progeny.

Teacher's Note:
1. Lamarck proposed use and disuse.

Answer: (a) fossils

Explanation:
1. Fossils are preserved remains or impressions of organisms in rocks; their study is palaeontology.

Teacher's Note:
1. Fossils give evidence of past life and evolutionary change.

Answer: (d) homologous structures

Explanation:
1. Divergent evolution produces homologous organs, for example forelimbs of whale, bat and human.

Teacher's Note:
1. Homology indicates common ancestry.

Answer: (c) convergent evolution

Explanation:
1. Unrelated organisms facing similar habitats develop structures of similar function but different origin.

Teacher's Note:
1. Wings of butterfly and bird are analogous.

Answer: (b) analogy

Explanation:
1. They serve the same function (swimming) but evolved independently in different groups.

Teacher's Note:
1. Hence the result of convergent evolution.

Answer: (a) Lichens

Explanation:
1. Lichens are very sensitive to air pollutants such as sulphur dioxide and do not grow in polluted areas.

Teacher's Note:
1. Their absence suggests polluted air.

Answer: (d) camouflage themselves against the background

Explanation:
1. On soot-darkened trees dark moths were not seen by predators, while light moths were picked off.

Teacher's Note:
1. This is natural selection in action.

Answer: (c) anthropogenic action

Explanation:
1. Human action (use of antibiotics, pesticides) selects resistant forms on a short time scale.

Teacher's Note:
1. Evolution is not always very slow.

Answer: (b) Galapagos Islands

Explanation:
1. Finches on the Galapagos had beaks adapted to different food sources, evolving from a seed-eating ancestor.

Teacher's Note:
1. This is a classic case of adaptive radiation.

Answer: (a) Alfred Wallace

Explanation:
1. Alfred Russel Wallace reached the idea of natural selection independently of Darwin.

Teacher's Note:
1. Their ideas were presented together in 1858.

Answer: (d) adaptive radiation

Explanation:
1. Adaptive radiation produces many forms from a common ancestor adapted to different habitats.

Teacher's Note:
1. Darwin's finches and Australian marsupials are examples.

Answer: (c) convergent evolution

Explanation:
1. Australian marsupials and placental mammals with similar roles (for example Tasmanian wolf and wolf) are examples.

Teacher's Note:
1. Placental wolf and Tasmanian wolf evolved separately.

Answer: (b) Adaptive ability is inherited

Explanation:
1. Darwinian variations are small, directionless and inheritable; acquired traits are not passed on.

Teacher's Note:
1. Ability to adapt is inherited, not acquired.

Answer: (a) branching descent and natural selection

Explanation:
1. All organisms are related by branching descent from a common ancestor, and natural selection acts on variations.

Teacher's Note:
1. Lamarck's concept was use and disuse.

Answer: (d) Darwin

Explanation:
1. Malthus argued that populations grow geometrically while resources grow arithmetically, which gave Darwin the idea of struggle for existence.

Teacher's Note:
1. Wallace was also influenced by it.

Answer: (c) evening primrose (Oenothera lamarckiana)

Explanation:
1. He observed large sudden variations in evening primrose and called them mutations.

Teacher's Note:
1. Mutations are random and directionless in the modern view.

Answer: (b) saltation

Explanation:
1. Saltation is a sudden large change that causes speciation, proposed by de Vries.

Teacher's Note:
1. Darwinian variations are small and gradual.