Zoology-Evolution

The theory of catastrophism was proposed by Georges Cuvier. According to this theory, Earth's history has been marked by sudden catastrophic events, such as floods or volcanic eruptions.
These catastrophic events caused mass extinctions, after which new species appeared.
Important facts for revision
• Catastrophism → sudden environmental disasters
• Proposed by → Georges Cuvier
Correct Answer
So, the correct answer is Georges Cuvier.

Biogenesis states that living organisms arise only from pre-existing living organisms.
This concept was supported by experiments of:
Redi
Spallanzani
Pasteur
Important facts
• Biogenesis → life from existing life
Correct Answer
So, the correct answer is biogenesis theory.

The chemical evolution theory proposes that life originated through the gradual combination of simple chemicals under suitable environmental conditions.
These reactions produced:
Amino acids
Sugars
Nucleotides
These molecules eventually formed primitive cells.

The primitive atmosphere contained methane, ammonia, hydrogen, and water vapour.
Since all the options listed are components of the primitive atmosphere, none of them is absent.

Louis Pasteur made major contributions to microbiology and medicine. He established the germ theory of disease, which states that microorganisms cause diseases.
He also developed techniques such as pasteurization to kill harmful microbes in food.
Important facts
• Pasteur → germ theory of disease
Correct Answer
So, the correct answer is germ theory of disease.

Louis Pasteur performed the famous swan-neck flask experiment.
He showed that boiled nutrient broth remained sterile if airborne microorganisms could not enter the flask. When the neck was broken, microbes appeared.
This experiment conclusively disproved spontaneous generation.
Important facts
• Swan-neck flask experiment → Louis Pasteur
Correct Answer
So, the correct answer is Louis Pasteur.

J. B. S. Haldane proposed that the early ocean contained a mixture of organic molecules formed from atmospheric reactions.
He described this ocean as a “hot dilute soup”, where organic compounds accumulated and eventually formed the first living organisms.
Important facts for revision
• “Hot dilute soup” → Haldane
Correct Answer
So, the correct answer is J. B. S. Haldane.

Van Helmont strongly supported the idea of spontaneous generation.
He even proposed a recipe claiming that mice could arise from wheat grains and dirty cloth left together for several weeks.
Later scientists such as Francesco Redi and Louis Pasteur experimentally disproved this theory.
Correct Answer
So, the correct answer is Van Helmont.

Abiogenesis refers to the concept that life originated from non-living matter. According to this idea, simple inorganic molecules under suitable environmental conditions gave rise to organic molecules, which eventually formed the first living organisms.
In modern biology, abiogenesis is often associated with the chemical evolution theory, which proposes that life gradually evolved from non-living chemical substances on early Earth.
This concept differs from biogenesis, which states that life arises only from pre-existing life.
Important facts for revision
• Abiogenesis → life from non-living matter
• Biogenesis → life from pre-existing life
Correct Answer
So, the correct answer is origin of life from non-living organisms.

The concept of spontaneous generation was first proposed by the Greek philosopher Aristotle.
According to this theory, living organisms could arise spontaneously from non-living matter, for example:
Maggots from decaying meat
Frogs from mud
Later experiments by Redi, Spallanzani, and Pasteur disproved this idea.
Important facts
• Spontaneous generation → proposed by Aristotle
Correct Answer
So, the correct answer is Aristotle.

Experiments by Lazzaro Spallanzani demonstrated that if broth was boiled and sealed properly, microorganisms did not grow.
This suggested that microorganisms come from existing microbes in air, not from spontaneous generation.
Important facts
• Spallanzani experiment → boiled broth stayed sterile
Correct Answer
So, the correct answer is Meat was not spoiled when heated and sealed in vessel.

Several scientists contributed to the understanding of the origin of life.
Correct associations:
Sidney Fox → Microspheres (protein-like structures formed from amino acids)
Oparin → Protobionts or coacervates
Haldane → Hot dilute soup theory
Spallanzani performed experiments that disproved spontaneous generation, not supported abiogenesis.
Correct Answer
So, the correct answer is Spallanzani – Abiogenesis.

According to the Oparin–Haldane hypothesis, the early Earth's atmosphere was reducing and contained gases such as:
Methane (CH₄)
Hydrogen (H₂)
Ammonia (NH₃)
Water vapour (H₂O)
Free oxygen (O₂) was absent in the primitive atmosphere.
Important facts for revision
Primitive atmosphere gases:
• CH₄, NH₃, H₂, H₂O
Correct Answer
So, the correct answer is Oxygen.

The chemical theory of evolution is supported by experimental evidence such as the Miller–Urey experiment.
This theory proposes that:
Organic molecules formed from inorganic compounds
These molecules gradually combined to form complex biological structures
Eventually, primitive life evolved
Important facts for revision
• Experimentally supported origin theory → chemical evolution
Correct Answer
So, the correct answer is chemical theory.

The primitive atmosphere of Earth consisted mainly of:
Ammonia (NH₃)
Methane (CH₄)
Hydrogen (H₂)
Water vapour (H₂O)
These gases created a reducing environment, which was favorable for chemical evolution.
Correct Answer
So, the correct answer is option (D), ammonia, methane, hydrogen and water.

Scientific evidence from radiometric dating of meteorites and rocks indicates that the Earth formed about 4.6 billion years ago.
This occurred during the early stages of the solar system formation, when dust and gas condensed to form planets.
Important facts for revision
• Age of Earth → 4.6 billion years
Correct Answer
So, the correct answer is 4.6 billion years ago.

The theory of special creation proposes that life was created by a supernatural power or divine being.
One of the strongest supporters of this theory was Father Suarez, a theologian who believed that all living organisms were created by divine intervention.
Correct Answer
So, the correct answer is Father Suarez.

The Oparin–Haldane hypothesis proposed that life originated through chemical evolution.
According to this hypothesis:
Early Earth had a reducing atmosphere
Energy from lightning, UV radiation, and volcanic heat caused chemical reactions
These reactions produced organic molecules from inorganic substances
Later, this hypothesis was experimentally tested by Miller and Urey.
Important facts for revision
• Chemical evolution theory → Oparin and Haldane
Correct Answer
So, the correct answer is Oparin and Haldane.

The Cosmozoic theory, also known as the Panspermia theory, suggests that life did not originate on Earth but came from outer space in the form of spores or microscopic organisms.
This idea was proposed by Richter and later supported by scientists like Arrhenius. According to this theory, life reached Earth through meteorites or cosmic dust.
Important facts for revision
• Cosmozoic theory → life came from outer space
• Proposed by → Richter
Correct Answer
So, the correct answer is Richter.

The theory of spontaneous generation suggested that living organisms could arise directly from non-living substancesunder favorable conditions.
Examples believed in the past included:
Maggots forming from decaying meat
Microbes appearing in broth
Correct Answer
So, the correct answer is organisms arose from non-living material.