Free Concept of Evolution MCQs with Answers

1. The forelimb of a whale, a bat and a human have the same arrangement of bones but perform different functions. Such organs are described as

• A. analogous
• B. homologous
• C. vestigial
• D. acquired

Explanation: Homologous organs share a common structural plan and a common embryonic origin because they were inherited from a shared ancestor, and their different uses are the result of divergent evolution. Analogous organs are the opposite case: same job, different structure and origin. Vestigial organs are reduced remnants that have lost their original function altogether.

2. The wing of an insect and the wing of a bird are said to be analogous because they

• A. develop from the same embryonic tissue
• B. contain the same bones in the same order
• C. perform the same function but differ in structure and origin
• D. are both reduced and non functional

Explanation: Both are used for flight, but a bird wing is a modified vertebrate forelimb with bone inside while an insect wing is an outgrowth of the body wall with no bone at all, so the resemblance is functional only. This is convergent evolution, in which unrelated groups meeting the same environmental demand arrive at similar solutions. Analogy therefore tells us about the environment, whereas homology tells us about ancestry.

3. Which of the following is a vestigial structure in the human body?

• A. Vermiform appendix
• B. Pancreas
• C. Diaphragm
• D. Thymus gland

Explanation: The appendix is the reduced remains of a large caecum that digests cellulose in herbivorous ancestors, and it can be removed with no loss of digestive function. Vestigial organs are evidence of evolution precisely because a designed structure would not carry a useless remnant. The pancreas and diaphragm are fully functional, and the thymus, though it shrinks after puberty, is essential for training T lymphocytes.

4. The most direct evidence for the course of evolution comes from

• A. comparative embryology
• B. vestigial organs
• C. biochemical similarity between proteins
• D. the fossil record

Explanation: Fossils are the only evidence that shows extinct organisms themselves, arranged in dated rock layers, so they give an actual sequence of change over time rather than an inference drawn from living species. The other three lines are powerful but indirect, since they compare organisms alive today and reason backwards. The fossil record is incomplete, which is its main limitation, not its reliability.

5. Archaeopteryx is regarded as a connecting link between

• A. fishes and amphibians
• B. amphibians and reptiles
• C. reptiles and birds
• D. reptiles and mammals

Explanation: Archaeopteryx had feathers and a wishbone like a bird but also teeth in its jaws, a long bony tail and clawed fingers like a reptile, so it carries characters of both classes. Such transitional fossils are exactly what common descent predicts and what a theory of separately created fixed types does not. The fish to amphibian link is filled by fossils such as Ichthyostega instead.

6. The fewer the differences in the amino acid sequence of cytochrome c between two species, the

• A. more distantly related they are
• B. more closely related they are
• C. larger their genomes must be
• D. faster their mutation rate must be

Explanation: Sequence differences accumulate by mutation after two lineages separate, so a small number of differences means little time has passed since they shared an ancestor. Human and chimpanzee cytochrome c is identical, while human and yeast differ at dozens of positions, and the pattern matches the tree built from anatomy and fossils. Genome size is unrelated to relatedness, as many amphibians have genomes far larger than ours.

7. The presence of pharyngeal (gill) pouches in the embryos of fish, birds and humans alike is evidence drawn from

• A. comparative anatomy of adults
• B. palaeontology
• C. biogeography
• D. comparative embryology

Explanation: Early vertebrate embryos resemble one another far more than the adults do, and structures such as pharyngeal pouches and a post anal tail appear even in species that never use them, because development follows an inherited common programme. In humans the pouches go on to form parts of the ear, tonsil and parathyroid rather than gills. Adult anatomy, fossils and distribution are separate lines of evidence.

8. Adaptive radiation is best illustrated by

• A. the two colour forms of the peppered moth
• B. the reduced human appendix
• C. Darwin's finches evolving different beak shapes from one ancestral species
• D. the similarity of cytochrome c in humans and chimpanzees

Explanation: Adaptive radiation is the spread of one ancestral species into many descendant species, each adapted to a different niche, which is exactly what happened when finches colonised the separate Galapagos islands. The peppered moth is a change in the frequency of two forms within a single species, not the origin of new ones. The appendix illustrates vestigial structures and cytochrome c illustrates molecular homology.

9. Evolution is best defined as

• A. gradual genetic change in populations over successive generations
• B. the growth of an individual from birth to adulthood
• C. the seasonal migration of animals
• D. the extinction of a single species

Explanation: Evolution acts on populations across generations, changing allele frequencies over time. An individual's own growth or a single extinction event is not evolution, since neither involves inherited change passed through a population.

10. The theory of evolution by natural selection was proposed independently by Darwin and

• A. Lamarck
• B. Alfred Russel Wallace
• C. Gregor Mendel
• D. Thomas Huxley

Explanation: Wallace reached the same conclusion while collecting in the Malay Archipelago, and his letter prompted the joint reading of both men's work in 1858. Mendel discovered inheritance, and Huxley defended Darwin, but neither proposed natural selection.