Origin of Life Theories Practice Questions
19 free Origin of Life Theories practice questions for the Zoology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Which theory of the origin of life suggests that life arrived on Earth from outer space via comets or meteorites?
- A Theory of Special Creation
- B Theory of Panspermia
- C Spontaneous Generation
- D Chemical Evolution
Correct answer: Theory of Panspermia
Panspermia, also known as the Cosmozoic theory, proposes that 'seeds' of life exist throughout the Universe and were delivered to Earth. Early Greek thinkers and some modern scientists support the possibility that resistant spores traveled through space.
In the famous Miller-Urey experiment, which of the following gases was NOT included in the simulated primitive atmosphere?
- A Methane (CH4)
- B Ammonia (NH3)
- C Molecular Hydrogen gas (H2)
- D Free Oxygen gas (O2)
Correct answer: Free Oxygen gas (O2)
The primitive Earth atmosphere was reducing and lacked free oxygen. The Miller-Urey experiment used methane, ammonia, water vapor, and hydrogen to simulate these early conditions.
The 'Oparin-Haldane' hypothesis is primarily based on which concept?
- A Life arose only from pre-existing living organisms
- B Abiogenesis through step-by-step chemical evolution
- C Life was created solely by a supernatural power
- D The first life forms were already complex eukaryotes
Correct answer: Abiogenesis through step-by-step chemical evolution
Oparin and Haldane proposed that life emerged from non-living matter through a series of chemical reactions in a 'primordial soup.' This involved the formation of organic monomers followed by complex polymers.
Which experiment is credited with conclusively disproving the Theory of Spontaneous Generation (Abiogenesis)?
- A Miller's spark-discharge experiment
- B Louis Pasteur's swan-neck flask experiment
- C Mendel's classic pea plant hybridization experiment
- D Morgan's Drosophila fruit fly experiments
Correct answer: Louis Pasteur's swan-neck flask experiment
Pasteur demonstrated that microorganisms only appeared in nutrient broth when exposed to pre-existing airborne microbes. His experiment proved 'Omne vivum ex vivo'—life comes only from life.
What are 'coacervates', as described by Oparin?
- A Primitive DNA-like nucleic acid molecules
- B Colloidal droplets of organic macromolecules
- C The first photosynthetic bacteria colonies
- D Meteorites containing trace amounts of amino acids
Correct answer: Colloidal droplets of organic macromolecules
Coacervates are spherical aggregations of lipid-like molecules that exhibit some properties of life, such as a simple boundary and the ability to absorb molecules. Oparin considered them a crucial step toward the first protocells.
The 'RNA World' hypothesis suggests that RNA was the first genetic material because it can:
- A Serve as a structural component of cell membranes
- B Survive temperatures above 500 degrees Celsius
- C Convert inorganic nitrogen into protein directly
- D Act as both a genetic code and a catalytic enzyme
Correct answer: Act as both a genetic code and a catalytic enzyme
RNA can store genetic information and perform biological catalysis (as ribozymes). This dual functionality solves the 'chicken or egg' problem of whether DNA or proteins came first.
According to modern cosmology, approximately how old is the universe?
- A About 4.6 billion years
- B About 13.8 billion years
- C About 6,000 years
- D More than 100 billion years
Correct answer: About 13.8 billion years
Measurements of the cosmic microwave background give the age of the universe as roughly 13.8 billion years. About 4.6 billion years is the age of the Earth and the Solar System.
Which of the following organic molecules was produced in Miller’s 1953 experiment?
- A ATP molecules used for cellular energy
- B Complete strands of double-helix DNA
- C Cellulose fibers found in plant cell walls
- D Amino acids like glycine and alanine
Correct answer: Amino acids like glycine and alanine
Miller observed the formation of several amino acids, which are the building blocks of proteins. This provided strong experimental evidence that organic molecules could form under prebiotic conditions.
What was the most significant change in the Earth's atmosphere that allowed for the evolution of aerobic life?
- A The very gradual formation of Earth's moon and tides
- B A series of massive global volcanic eruptions
- C The gradual cooling of the Earth's outer crust
- D The appearance of oxygen-releasing cyanobacteria
Correct answer: The appearance of oxygen-releasing cyanobacteria
Cyanobacteria performed oxygenic photosynthesis, releasing oxygen as a byproduct. Over time, this transformed the reducing atmosphere into an oxidizing one, leading to the 'Oxygen Revolution'.
Sydney Fox's 'Protenoid Microspheres' were formed by:
- A Mixing amino acids with concentrated salt water
- B Subjecting methane gas to intense UV radiation
- C Isolating bacteria from deep ocean vents
- D Heating dry amino acids and then adding water
Correct answer: Heating dry amino acids and then adding water
When dry amino acids are heated, they form protenoids (thermal proteins). When these are dissolved in water, they spontaneously form microspheres, which Fox proposed as precursors to living cells.
The theory of 'Catastrophism', which attempted to explain the fossil record while supporting Special Creation, was proposed by:
- A Georges Cuvier
- B Charles Darwin
- C Jean-Baptiste Lamarck
- D Alfred Russel Wallace
Correct answer: Georges Cuvier
Cuvier proposed that Earth had been shaped by sudden, violent events (catastrophes) that caused mass extinctions. He believed that after each event, new species were created to repopulate the area.
The first living organisms on Earth are believed to have been:
- A Anaerobic heterotrophs
- B Aerobic autotrophs
- C Eukaryotic algae
- D Photosynthetic plant organisms
Correct answer: Anaerobic heterotrophs
Early Earth lacked oxygen, so the first life forms must have been anaerobic. They were likely heterotrophs that absorbed organic molecules from the 'primordial soup' for energy.
Which geological era is known as the 'Age of Mammals'?
- A Paleozoic
- B Mesozoic
- C Proterozoic
- D Cenozoic
Correct answer: Cenozoic
The Cenozoic era, following the extinction of dinosaurs at the end of the Mesozoic, saw the rapid diversification and dominance of mammals. It continues to the present day.
The presence of fossils of the same extinct reptile, Mesosaurus, in both South America and Africa supports which theory?
- A Continental Drift
- B Spontaneous Generation
- C Theory of Eternity of Life
- D Biogenesis
Correct answer: Continental Drift
Mesosaurus was a freshwater reptile that could not have crossed the Atlantic Ocean. Its presence on both continents provides evidence that South America and Africa were once joined in a single landmass.
Which of the following is considered a 'living fossil'?
- A Coelacanth
- B Archaeopteryx
- C Trilobite
- D Dodo bird
Correct answer: Coelacanth
A living fossil is an extant species that closely resembles organisms otherwise known only from the fossil record. The Coelacanth was thought to be extinct for millions of years until a living specimen was caught in 1938.
Francesco Redi’s experiment with decaying meat and jars was designed to test:
- A The Spontaneous Generation of maggots
- B The Law of Segregation
- C The effects of UV light on bacteria
- D The composition of the primitive atmosphere
Correct answer: The Spontaneous Generation of maggots
Redi showed that maggots only appeared on meat if flies were allowed to land and lay eggs. This was one of the first controlled experiments to challenge the idea that life arises spontaneously from rotting matter.
The 'Endosymbiotic Theory' explains the origin of which cellular organelles?
- A Mitochondria and Chloroplasts
- B Ribosomes and Golgi bodies
- C Nucleus and Endoplasmic Reticulum
- D Lysosomes and Vacuoles
Correct answer: Mitochondria and Chloroplasts
Proposed by Lynn Margulis, this theory suggests that mitochondria and chloroplasts originated as free-living bacteria that were engulfed by a host cell. Over time, they formed a symbiotic relationship and became integral organelles.
What is the estimated age of the Earth according to radioactive dating?
- A 4.5 billion years
- B 2.5 billion years
- C 10 billion years
- D 6,000 years
Correct answer: 4.5 billion years
Scientific evidence from the radiometric dating of meteorite samples and the oldest known Earth and Lunar samples indicates the Earth formed approximately 4.54 billion years ago.
Which scientist proposed the 'Theory of Eternity of Life', suggesting life has no beginning or end?
- A Richter
- B Preyer
- C Helmholtz
- D Aristotle
Correct answer: Preyer
Preyer and others suggested that life has always existed in the universe in some form. This theory argues against a specific 'origin' of life, though it lacks experimental support and contradicts the Big Bang model.