Biology: Evolution of Life

Total Questions: 23

1. Choose the correct chronological order of given Epochs, oldest one will come first: [Chhattisgarh P.C.S. (Pre) 2021]

(a) Holocene > Pleistocene > Pliocene > Miocene > Eocene
(b) Eocene > Miocene > Pliocene > Pleistocene > Holocene
(c) Eocene > Miocene > Pleistocene > Pliocene > Holocene
(d) Holocene > Pliocene > Pleistocene > Miocene > Eocene

Correct Answer: (b) Eocene > Miocene > Pliocene > Pleistocene > Holocene

Solution:The chronological order of Epochs (from oldest to newest) is as follows:
Paleocene > Eocene > Oligocene > Miocene > Pliocene > Pleistocene > Holocene

Paleocene:

The first epoch of the Cenozoic (66-56 million years ago), following the extinction of the dinosaurs. Modern placental mammals began to diversify during this time.

Eocene:

The second epoch (56-33.9 million years ago), marked by the further evolution of mammals, including the appearance of horses and primates. Whales also evolved during this period.

Oligocene:

The third epoch (33.9-23 million years ago), characterized by the expansion of grasslands and the evolution of new mammal species, such as the first elephants, cats, and dogs.

Miocene:

The fourth epoch (23-5.3 million years ago), saw the rise of grazing animals and further evolution of mammals adapted to the expanding grasslands.

Pliocene:

The fifth epoch (5.3-2.6 million years ago), which saw a transition from warm, humid climates to cooler, drier conditions and the beginning of the ice ages in the Northern Hemisphere.

2. Which of the following gases was absent in the atmosphere of the primitive Earth? [U.P. RO/A.R.O. (Mains) 2016]

(a) Methane
(b) Ammonia
(c) Oxygen
(d) Carbon dioxide

Correct Answer: (c) Oxygen

Solution:Primitive Earth's atmosphere was rich in methane, ammonia, water vapour, carbon dioxide, carbon monoxide, nitrogen, hydrogen, neon, etc. It was a reducing atmosphere, with no free oxygen. It is likely that hundreds of millions of years separated the first biological production of oxygen by unicellular organisms and its eventual accumulation in the atmosphere.

3. Consider the following statements : [I.A.S. (Pre) 2018]

The Earth's magnetic field has reversed every few hundred thousand years.
When the Earth was created more than 4000 million years ago, there was 54% oxygen and no carbon dioxide.
When living organisms originated, they modified the early atmosphere of the Earth.

Which of the statements given above is/are correct?

(a) 1 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

Correct Answer: (c) 1 and 3 only

Solution:Over the history of the Earth, the magnetic field has reversed every several hundred thousand years. Over the last 5 million years, the Earth's magnetic field reversed itself at least 20 times. Over the last 20 million years, the reversal happens about every 200 thousand to 300 thousand years. However, it has been about 780 thousand years since the last reversal. Hence, statement 1 is correct.
When Earth was created, there was no oxygen in the atmosphere. Oxygen, although always present in compounds in Earth's interior, atmosphere, and oceans, did not begin to accumulate in the atmosphere as oxygen gas (O₂). The earliest atmosphere contained carbon dioxide, methane, water vapour, carbon monoxide, ammonia, nitrogen, hydrogen, etc. Hence, statement 2 is incorrect.
When living organisms originated, they modified the early atmosphere of the Earth. However, it is likely that hundreds of millions of years separated the first biological production of oxygen by unicellular organisms and its eventual accumulation in the atmosphere. Thus, statement 3 is correct.

4. According to recent proof, the life on Earth emerged approximately — [46th B.P.S.C. (Pre) 1995]

(a) Before 20,000 years
(b) Before 2,000,000 years
(c) Before 20,000,000 years
(d) Before 2,000,000,000 years

Correct Answer: (d) Before 2,000,000,000 years

Solution:The age of the Earth is about 4.6 billion years. This dating is based on evidence from radiometric age dating of meteorite materials and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples. According to recent proof, the life on Earth emerged about 2,000,000,000 years ago.

5. Which is the oldest organism on Earth? [U.P.P.C.S. (Spl.) (Mains) 2008]

(a) Blue-green algae
(b) Fungi
(c) Amoeba
(d) Euglena

Correct Answer: (a) Blue-green algae

Solution:Blue-green algae is the oldest organism on Earth. They obtain their energy through photosynthesis. They are also known as Cyanobacteria. By producing gaseous oxygen as a by-product of photosynthesis, they played a greater role in dramatically changing life forms on Earth by stimulating biodiversity.

6. The book, The Origin of Species was written by : [65th B.P.S.C. (Pre) 2019]

(a) Linnaeus
(b) Lamarck
(c) Mendel
(d) Darwin
(e) None of the above/More than one of the above

Correct Answer: (d) Darwin

Solution:Charles Darwin explained natural selection in his book 'The Origin of Species' (1859; Full Title - On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life). It is considered to be the foundation of evolutionary biology.

7. Darwin's theory of natural selection is based on - [M.P.P.C.S. (Pre) 1997]

(a) Overproduction
(b) Struggle for existence and variation
(c) Survival of the fittest
(d) All of the above

Correct Answer: (d) All of the above

Solution:Charles Robert Darwin was an English geologist and best known for his contribution to evolution theory. Darwin published his theory of evolution in his book 'On the Origin of Species' in 1859. It states that all species of organisms arise and develop through the natural selection of small, inherited variations that increase the individual's ability to compete, survive, and reproduce. It is called Darwinian theory.

8. Who propounded the theory of evolution? [M.P.P.C.S. (Pre) 2010]

(a) Spencer
(b) Darwin
(c) Wallace
(d) Huxley

Correct Answer: (b) Darwin

9. Who explained first the evolution of life? [43rd B.P.S.C. (Pre) 1999]

(a) Newton
(b) Einstein
(c) Charles Darwin
(d) Lamarck

Correct Answer: (d) Lamarck

Solution:French biologist Lamarck is best known for his "Theory of Inheritance of Acquired Characters", first presented in 1801. He was the first person to explain the theory of evolution to the public. In 1809, this theory was published in his book 'Philosophie Zoologique'.

Lamarck's theory, also known as Lamarckism, proposed that evolutionary change could be driven by the inheritance of acquired traits. key component of Lamarckism was the idea that organisms could develop or lose traits based on their use or disuse during their lifetime. For example, if an organism frequently used a particular limb, it would become stronger and that strength would be passed on to its offspring.

In his book, Lamarck outlined his theory of evolution, including the concept of the inheritance of acquired characteristics. While Lamarck's specific mechanism for inheritance is not supported by modern genetics, his ideas were influential in sparking early scientific inquiry into evolution. His work laid some groundwork for later evolutionary theories, such as Darwin's theory of natural selection.

10. The mutation theory of evolution was enunciated by [U.P.P.C.S. (Pre) 2005]

(a) Huxley
(b) Darwin
(c) Lamarck
(d) Hugo de Vries

Correct Answer: (d) Hugo de Vries

Solution:Hugo De Vries is known for his mutation theory of evolution. According to him, new species are not formed by continuous variations but by the sudden appearance of variations, which he named as mutations. He stated that mutations are heritable and persist in successive generations.

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