Every Book Back multiple-choice question from Evolution (12th Standard Zoology, Samacheer Kalvi) — each with the correct option highlighted and a clear, worked explanation. Free to read in English and Tamil.
Q1
The first life on earth originated
- A. in air
- B. on land
- C. in waterCorrect
- D. on mountain
Explanation. The first life on Earth originated in primeval water bodies where organic molecules spontaneously self-assembled. Water provided a protected environment and essential nutrients for early biochemical reactions to occur.
Q2
Who published the book "Origin of species by Natural Selection" in 1859?
- A. Charles DarwinCorrect
- B. Lamarck
- C. Weismann
- D. Hugo de Vries
Explanation. Charles Darwin published his groundbreaking book on evolution in 1859. In this work, he introduced the theory of natural selection as the primary mechanism for evolutionary change and diversity among species.
Q3
Which of the following was the contribution of Hugo de Vries?
- A. Theory of mutationCorrect
- B. Theory of natural Selection
- C. Theory of inheritance of acquired characters
- D. Germplasm theory
Explanation. Hugo de Vries proposed the mutation theory of evolution based on his experiments with the evening primrose. He argued that sudden, random, and heritable changes are the main drivers of new species formation.
Q4
The wings of birds and butterflies is an example of
- A. Adaptive radiation
- B. convergent evolutionCorrect
- C. divergent evolution
- D. variation
Explanation. The wings of birds and butterflies are analogous structures. They possess different anatomical and developmental origins but serve the same function of flight, which is a classic example of convergent evolution.
Q5
The phenomenon of "Industrial Melanism" demonstrates
- A. Natural selectionCorrect
- B. induced mutation
- C. reproductive isolation
- D. geographical isolation
Explanation. Industrial melanism shows natural selection in action. As soot darkened tree trunks during the industrial revolution, predatory birds easily spotted light-colored moths. This selected for dark-colored moths, raising their survival rate.
Q6
Darwin’s finches are an excellent example of
- A. connecting links
- B. seasonal migration
- C. adaptive radiationCorrect
- D. parasitism
Explanation. Darwin's finches are a classic example of adaptive radiation. A single ancestral species migrated to different islands of the Galapagos, evolving distinct beak shapes to exploit diverse food resources.
Q7
Who proposed the Germplasm theory?
- A. Darwin
- B. August WeismannCorrect
- C. Lamarck
- D. Alfred Wallace
Explanation. August Weismann proposed the germplasm theory, which states that heritable traits are transmitted solely by germ cells. He disproved Lamarck's theory of inheritance of acquired characters by cutting off mice tails.
Q8
The age of fossils can be determined by
- A. electron microscope
- B. weighing the fossils
- C. carbon datingCorrect
- D. analysis of bones
Explanation. The age of fossils can be determined using radiometric carbon dating. This absolute dating technique measures the decay of radioactive isotopes like carbon-14 in organic remains to find their precise age.
Q9
Fossils are generally found in
- A. igneous rocks
- B. metamorphic rocks
- C. volcanic rocks
- D. sedimentary rocksCorrect
Explanation. Fossils are typically found in sedimentary rocks. When organic remains are buried in sand and mud, layers of sediments harden over time, protecting and preserving these biological specimens from decaying.
Q10
Evolutionary history of an organism is called
- A. ancestry
- B. ontogeny
- C. phylogenyCorrect
- D. paleontology
Explanation. Phylogeny refers to the evolutionary history and line of descent of a species or group of organisms. It is often represented diagrammatically as a phylogenetic tree to show evolutionary relationships.
Q11
The golden age of reptiles was
- A. Mesozoic eraCorrect
- B. Cenozoic era
- C. Paleozoic era
- D. Proterozoic era
Explanation. The Mesozoic era is known as the golden age of reptiles because dinosaurs and other massive reptiles dominated terrestrial, aquatic, and aerial environments during this geologic timeframe.
Q12
Which period was called “Age of fishes”?
- A. Permian
- B. Triassic
- C. DevonianCorrect
- D. Ordovician
Explanation. The Devonian period of the Paleozoic era is widely called the age of fishes. This period witnessed a massive diversification of marine life, including the emergence of the earliest jawed and bony fishes.
Q13
Modern man belongs to which period?
- A. QuaternaryCorrect
- B. Cretaceous
- C. Silurian
- D. Cambrian
Explanation. Modern humans emerged and evolved during the Quaternary period of the Cenozoic era. This geological period is characterized by ice ages, the rise of human civilizations, and the decline of other mammalian species.
Q14
The Neanderthal man had the brain capacity of
- A. 650 – 800cc
- B. 1200cc
- C. 900cc
- D. 1400ccCorrect
Explanation. The Neanderthal man had a remarkable cranial capacity of approximately 1400 cc. This brain size is comparable to, or sometimes slightly larger than, the average brain size of modern humans.
Q15
According to Darwin, the organic evolution is due to
- A. Intraspecific competition
- B. Interspecific competitionCorrect
- C. Competition within closely related species.
- D. Reduced feeding efficiency in one species due to the presence of interfering species.
Explanation. According to Darwin, interspecific competition is a major driver of organic evolution. Struggle between different species for shared resources like food and space drives natural selection and adaptation to niches.
Q16
A population will not exist in Hardy-Weinberg equilibrium if
- A. Individuals mate selectivelyCorrect
- B. There are no mutations
- C. There is no migration
- D. The population is large
Explanation. Hardy-Weinberg equilibrium assumes random mating. Selective mating violates this assumption, causing allele and genotype frequencies to change over generations, thus disrupting the equilibrium.
