Evolutionary Biology & Chemical Origins Quiz

🧪 Evolutionary Biology & Chemical Origins Quiz

Question 1

Two substances $A$ ($t_{1/2} = 5\text{ min}$) and $B$ ($t_{1/2} = 15\text{ min}$) are taken in such a way that initially $[A] = 4[B]$. The time after which both the concentrations will be equal is (Assume that the reaction is first-order):

$5\text{ min}$
$15\text{ min}$
$20\text{ min}$
Concentration can never be equal

Correct Answer: Option (2)

Explanation

For a first-order reaction, $[A]_t = [A]_0 \left(\frac{1}{2}\right)^{t/t_{1/2}}$.
Set $4[B]_0 (1/2)^{t/5} = [B]_0 (1/2)^{t/15}$
$\Rightarrow 4 = 2^{2t/15} \Rightarrow t = 15$ min.

Question 2

Read two statements (a) and (b) carefully and select the correct option regarding them:
**(a)** The first life on earth was chemoautotrophic and anaerobic.
**(b)** Protobionts could exhibit simple metabolism and reproduction.

Statement (a) is correct but statement (b) is incorrect
Statement (a) is incorrect but statement (b) is correct
Both statements are correct
Both statements are incorrect

Correct Answer: Option (3)

Explanation

Both statements are correct. First life was anaerobic chemoautotrophs; protobionts (coacervates, microspheres) showed simple metabolism and reproduction.

Question 3

Which statement is incorrect about the changes that have occurred on earth since its origin?

Most of the birds evolved into mammals
Multicellular organisms evolved from unicellular organisms
The first organisms that invaded land were plants
Life originated in the water

Correct Answer: Option (1)

Explanation

Birds did not evolve into mammals; birds evolved from theropod dinosaurs, mammals from therapsids.

Question 4

Select the option which has correct sequence of change in mode of nutrition in earlier prokaryotic organisms:
**(a)** Oxygenic photosynthesis
**(b)** Chemoautotrophism
**(c)** Chemoheterotrophism
**(d)** Non-oxygenic photosynthesis

(c) $\rightarrow$ (b) $\rightarrow$ (d) $\rightarrow$ (a)
(b) $\rightarrow$ (c) $\rightarrow$ (d) $\rightarrow$ (a)
(c) $\rightarrow$ (d) $\rightarrow$ (b) $\rightarrow$ (a)
(d) $\rightarrow$ (c) $\rightarrow$ (b) $\rightarrow$ (a)

Correct Answer: Option (1)

Explanation

Correct sequence: Chemoheterotroph → Chemoautotroph → Non‑oxygenic photosynthesis → Oxygenic photosynthesis.

Question 5

According to Oparin-Haldane theory, life has come from:

Pre-existed non-living organic molecules
Pre-existed living organic molecules
Some other planet
Decaying and rotting material

Correct Answer: Option (1)

Explanation

Oparin-Haldane proposes life arose from non-living organic molecules formed in the primitive reducing atmosphere.

Question 6

Mark the incorrect statement regarding the Big Bang theory that attempts to explain the origin of the universe.

It talks of a singular, huge explosion unimaginable in physical terms.
The universe expanded and hence, the temperature came down.
Water vapour, methane, and ammonia released from molten mass covered the earth surface.
Formation of life was preceded by chemical evolution.

Correct Answer: Option (3)

Explanation

Statement (3) describes Earth's early atmosphere, not the Big Bang theory.

Question 7

Earth was originated before:

4.5 billion years ago
2.5 billion years ago
1.5 billion years ago
2 billion years ago

Correct Answer: Option (1)

Explanation

Earth originated about 4.5 billion years ago.

Question 8

Which of the following amino acids was not formed during the simulation experiment of Stanley Miller?

Alanine
Aspartic acid
Glycine
Glutamic acid

Correct Answer: Option (4)

Explanation

Miller's experiment produced Glycine, Alanine, and Aspartic acid, not Glutamic acid.

Question 9

The first cellular form of life originated before how many years?

3 billion years ago
4 billion years ago
2000 million years ago
0.5 million years ago

Correct Answer: Option (3)

Explanation

First cellular life originated about 2000 million (2 billion) years ago.

Question 10

Study of history of life forms on earth is called:

Exobiology
Cosmology
Evolutionary biology
Ethology

Correct Answer: Option (3)

Explanation

Evolutionary biology studies the history of life forms on Earth.

Question 11

Amphibians are supposed to have evolved from the most primitive fish with stout and strong fins that could move on land and water. This was:

Jawless fish
Coelacanth
Chimera
Ichthyosaurs

Correct Answer: Option (2)

Explanation

Coelacanth (lobe-finned fish) is considered the ancestor of amphibians.

Question 12

Read the following statements (A-D) and select the correct option:
**(A)** Huge clusters of galaxies comprise the universe.
**(B)** Galaxies contain stars and clouds of gas and dust.
**(C)** Considering the size of the universe, Earth is indeed a speck.
**(D)** The gases condensed under gravitation and formed the galaxies of the present day universe.
How many of the above statements are correct?

One
Two
Three
Four

Correct Answer: Option (4)

Explanation

All four statements are correct.

Question 13

Huge clusters of galaxies comprise the universe. The galaxies of the present day universe were formed by:

Water vapour, methane, and ammonia released from molten mass
The expansion of universe (the universe expanded and hence, the temperature came down and galaxies are formed)
Gaseous condensation under gravitation
The UV rays

Correct Answer: Option (3)

Explanation

Galaxies formed by gravitational condensation of gases after the Big Bang.

Question 14

Protobionts were synthesized artificially by:

Sydney Fox
Miller and Urey (in 1953)
Altman (1980)
Oparin and Haldane

Correct Answer: Option (1)

Explanation

Sydney Fox synthesized proteinoid microspheres (protobionts).

Question 15

Evolution from a simple cell to the current diverse life forms is:

Chemical evolution
Biological evolution
Organic evolution
Both (2) and (3)

Correct Answer: Option (4)

Explanation

Diversification from simple cell is biological and organic evolution.

Question 16

Which of the following is a true statement?

The primitive atmosphere had $20\%$ oxygen just like today.
The reducing primitive atmosphere contributed to the origin of life and the oxidizing one today hinders it.
The primitive atmosphere was an oxidizing one and today's is a reducing one, making photosynthesis possible.
It took so long for prokaryote evolution because the primitive atmosphere screened out the UV radiations from the sun.

Correct Answer: Option (2)

Explanation

Reducing atmosphere allowed organic accumulation; oxidizing atmosphere prevents spontaneous abiogenesis.

Question 17

The diagram represents Miller's experiment. Choose the correct combination of labelling:
*(Note: Standard labelling represents A: electrodes, B: reactants flask, C: condenser, D: vacuum line, E: U-trap)*

$A$ - electrodes, $B$ - $\text{NH}_3 + \text{H}_2 + \text{H}_2\text{O} + \text{CH}_4$, $C$ - Cold water, $D$ - vacuum, $E$ - U-trap
$A$ - electrodes, $B$ - $\text{NH}_3 + \text{H}_2 + \text{CO}_2 + \text{CH}_4$, $C$ - hot water, $D$ - vacuum, $E$ - U-trap
$A$ - electrodes, $B$ - $\text{NH}_3 + \text{H}_2\text{O}$, $C$ - hot water, $D$ - tap, $E$ - U-trap
$A$ - electrodes, $B$ - $\text{NH}_3 + \text{H}_2 + \text{H}_2\text{O} + \text{CH}_4$, $C$ - steam, $D$ - vacuum, $E$ - U-trap

Correct Answer: Option (1)

Explanation

Correct labelling: A‑electrodes, B‑NH₃+H₂+H₂O+CH₄, C‑cold water, D‑vacuum, E‑U‑trap.

Question 18

Which of the following giant molecules would not have arisen as the first non-cellular forms of life?

$\text{dsDNA}$
Protein
Polysaccharides
Lipid

Correct Answer: Option (1)

Explanation

dsDNA arose later; early non‑cellular forms used RNA, proteins, lipids, polysaccharides.

Question 19

Consider the following four statements (A-D) and select the option which includes all the correct ones only:
**(A)** The universe is very old, almost 10 billion years.
**(B)** Huge clusters of galaxies comprise the universe.
**(C)** Considering the size of the universe, Earth is indeed a speck.
**(D)** Special creation theory exhibits religious aspects.

Statements A, B & D
Statements A & B
Statements C & D
Statements B, C & D

Correct Answer: Option (4)

Explanation

Universe is ~20 billion years (A incorrect). B, C, D are correct.

Question 20

Which of these are considered most essential in the origin of life?

Enzymes
Nucleic acids
Carbohydrates
Lipids

Correct Answer: Option (2)

Explanation

Nucleic acids (RNA) are considered most essential (RNA World hypothesis).

Question 21

Choose the correct sequence of compounds in the following which formed during the origin of life:
**(A)** Prokaryotes
**(B)** Coacervates
**(C)** $\text{CH}_4$, $\text{HCN}$
**(D)** Ketones/Aldehydes

D, C, A, B
C, D, B, A
C, A, B, D
C, D, A, B

Correct Answer: Option (2)

Explanation

Correct sequence: CH₄/HCN → ketones/aldehydes → coacervates → prokaryotes.

Question 22

The theory that living organisms on the Earth came from outer space is based on the study of:

Igneous rocks
Sedimentary rocks
Meteorites
Moon soil

Correct Answer: Option (3)

Explanation

Panspermia theory is supported by organic molecules found in meteorites.

Question 23

Oxygen in the atmosphere was formed by:

Evaporation of water
Photosynthesis of blue-green algae
Metabolism of microorganisms
Decaying organisms

Correct Answer: Option (2)

Explanation

Oxygen in atmosphere came from photosynthesis of cyanobacteria (blue‑green algae).

Question 24

The theory of spontaneous generation of life says that:

Life originated from decaying and rotting matter like straw, mud, etc.
Life came on Earth from outer space.
Life comes from pre-existing life only.
Life started with the replication of self-replicating metabolic capsules.

Correct Answer: Option (1)

Explanation

Spontaneous generation claimed life arose from decaying matter; disproved by Pasteur.

Question 25

According to Oparin's theory of the origin of life:

Abiogenesis $\rightarrow$ Biogenesis $\rightarrow$ Abiogenesis forever
Abiogenesis $\rightarrow$ Biogenesis $\rightarrow$ Biogenesis forever
Biogenesis $\rightarrow$ Abiogenesis $\rightarrow$ Biogenesis forever
Biogenesis $\rightarrow$ Abiogenesis $\rightarrow$ Abiogenesis forever

Correct Answer: Option (2)

Explanation

Oparin: abiogenesis initially, then biogenesis forever.

Question 26

In the simulation experiment of Stanley Miller, the compartments/processes (A), (B), and (C) shown in the diagram correspond to:
*(Refer to the standard experimental setup: A is the spark discharge chamber, B is the cooling condenser, and C is the collection trap)*

(A) Raining, (B) Primitive atmosphere, (C) Hot dilute soup
(A) Hot dilute soup, (B) Raining, (C) Primitive atmosphere
(A) Primitive atmosphere, (B) Raining, (C) Hot dilute soup
(A) Raining, (B) Hot dilute soup, (C) Primitive atmosphere

Correct Answer: Option (3)

Explanation

A: primitive atmosphere (spark), B: raining (condenser), C: hot dilute soup (trap).

Question 27

The concept of chemical evolution of life is based on:

Effect of solar radiations on chemicals
Interaction of water, air, and clay under intense heat
Combination of chemicals under hot, moist environmental conditions
Crystallisation of chemicals

Correct Answer: Option (3)

Explanation

Chemical evolution: combination of chemicals under hot, moist conditions.

Question 28

Select the correct sequence of evolution:

Sauropsid $\rightarrow$ Thecodont $\rightarrow$ Lizard
Synapsid $\rightarrow$ Pelycosaurs $\rightarrow$ Bird
Sauropsid $\rightarrow$ Thecodont $\rightarrow$ Crocodile
Synapsid $\rightarrow$ Thecodont $\rightarrow$ Mammals

Correct Answer: Option (3)

Explanation

Sauropsid → Thecodont → Crocodile (correct lineage).

Question 29

For a first-order reaction with a half-life ($t_{1/2}$) of $10\text{ min}$, if the initial concentration is $10\text{ mol L}^{-1}$, the time after which it is reduced to $2.5\text{ mol L}^{-1}$ is:

$10\text{ min}$
$20\text{ min}$
$30\text{ min}$
$40\text{ min}$

Correct Answer: Option (2)

Explanation

$[A]_t = [A]_0 (1/2)^n$; $2.5 = 10 (1/2)^n \Rightarrow n=2$; $t = 2 \times 10 = 20$ min.

Question 30

Evolutionary biology is the study of the history of life forms on Earth. While evolution tells the story of the origin of life and the evolution of life forms or biodiversity on planet Earth, it must be understood against the background of the evolution of the universe itself. According to modern physical cosmology, the universe is:

Expanding
Contracting
Static
In the second half of its cycle

Correct Answer: Option (1)

Explanation

Modern cosmology confirms the universe is expanding (Hubble's law, CMBR).

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