Evolution Mock Test – Class 12 Biology

1. Population P is at Hardy-Weinberg equilibrium with . Population Q is also at equilibrium but has . Which relationship is correct?

2. A geological diagram shows a plant lineage splitting into several branches, some of which terminate in older periods while others persist into much younger strata. What is the most appropriate interpretation?

3. A population initially experiences stabilising selection on body size. After a long environmental shift, one larger phenotype gains the highest reproductive success and remains favoured for many generations. Which change in the phenotype distribution is expected?

4. A graph has phenotypic value on the x-axis and frequency of individuals on the y-axis. After selection, the peak remains centred near the original intermediate phenotype but becomes taller and narrower, with fewer individuals at both extremes. The pattern represents:

5. Assertion: Lamarck's use-and-disuse explanation is not the accepted basis for Darwinian natural selection.
Reason: Darwinian selection depends on differential reproduction of heritable variants rather than inheritance of modifications acquired through use or disuse.

6. A new island population begins with allele M at an unusually high frequency because the first colonists carried M by chance. Later, mainland migration becomes frequent, but M also gives higher reproductive success on the island. Which statement best describes the expected evolutionary history?

7. Darwin's finches and Australian marsupials differ greatly in their anatomy and habitats. Nevertheless, both qualify as adaptive radiations because each case involves:

8. A small island population begins with allele frequencies strongly different from the mainland because of founder effect. Several generations later, a permanent land connection forms and large numbers of mainland individuals migrate to the island and reproduce every generation. What is the most plausible long-term effect?

9. One ancestral finch population diversifies into several species specialised for different foods. On another continent, unrelated bird lineages independently evolve some similar beak shapes for comparable foods. Which pair of evolutionary processes is represented?

10. Ten replicate populations experience the same environment. In every replicate, phenotype H leaves more offspring than phenotype L, and H increases in frequency in all ten populations. Which pattern would most strongly distinguish this result from pure genetic drift?

11. Early embryos of several vertebrates display comparable structures in the region behind the head, yet the adult organisms develop very different respiratory and feeding structures. The observation is best interpreted as:

12. Arrange the following events into a coherent population-level evolutionary sequence.
P. Mutation or recombination generates heritable variation.
Q. Individuals carrying different variants experience different population processes or reproductive outcomes.
R. Allele frequencies change across generations.
S. Population genetic composition becomes different from its earlier state.

13. Two populations experience different local selection, but heavy migration continues between them every generation. Population P favours allele A, while Population Q favours allele a. Which outcome is most plausible?

14. Reproductive output is measured for a heritable phenotype distributed from low to high values.

If the environment remains unchanged, the most likely result is:

15. A population has allele frequencies and , but the observed genotype frequencies are , and . Which conclusion is strongest?

16. A population has allele frequencies and , but its observed genotype frequencies are , and . Which conclusion is best supported?

17. Pasteur-type experiments support biogenesis under present experimental conditions, while the Oparin-Haldane hypothesis concerns the first origin of life under ancient primitive-Earth conditions. Why are these ideas not necessarily contradictory?

18. Oparin-Haldane chemical evolution is most coherently represented by which order?
P. Simple inorganic substances under primitive-Earth conditions
Q. Formation of organic molecules
R. Increasing chemical complexity before the first living systems
S. Biological evolution of living populations after life has arisen

19. A population is monitored while a stable environmental pressure acts.

Which inference is best supported?

20. Match each evidence type with the relation it most directly contributes to evolutionary inference. A Column II entry is used once.

21. A heritable trait increases reproductive success in Environment P. The population later enters Environment Q, where the same trait reduces access to food. The most defensible prediction is that:

22. A bird population feeds on two abundant seed types: very small seeds and very large seeds. Small-beaked birds efficiently use the small seeds, large-beaked birds efficiently use the large seeds, but intermediate beaks handle neither resource well. Persistent selection would most likely:

23. Palaeontologists compare two hypotheses for a major dinosaur extinction. Both predict disappearance of the same dinosaur lineages, but they predict different accompanying environmental signatures. Fossil evidence confirms the extinction boundary but the environmental signatures remain incomplete. What can be concluded most securely?

24. Arrange the following cultural events from earlier to later according to the stated chronology.
P. Prehistoric cave art around
Q. Agriculture around
R. Increasingly settled human communities following agriculture

25. A population contains alleles A, a, B and b before reproduction. Offspring show several genotype combinations that were absent among their parents, but no new allelic state is detected at either locus. Which process most directly generated the new genetic combinations?

26. Use the following text-described vertebrate figure. An early reptile node divides into Branch P and Branch Q. Branch P contains pelycosaur- and therapsid-associated forms and ends in mammalian descendants. Branch Q contains thecodont- and dinosaur-associated forms and also gives rise to surviving reptilian and bird lineages. Which conclusion is best supported?

27. Four descriptions of Homo erectus are proposed.

Which record is internally consistent?

28. Around , a human population increasingly depends on agriculture rather than a fully mobile subsistence pattern. In the stated cultural sequence, the most likely associated later development is:

29. Assertion: Mutation and recombination alone do not determine which heritable variants will become common in a population.
Reason: The later frequencies of variants can be altered by natural selection, gene flow and genetic drift.

30. Use the developmental comparison described below. Embryos P, Q and R belong to different vertebrate groups. At an early stage, each shows a comparable series of structures in the pharyngeal region, but their later adult structures and functions differ substantially. The comparison most strongly supports:

31. Early embryos of several vertebrates share developmental features, but none passes through the fully formed adult stage of another living vertebrate. Which statement best captures the evidential value and limitation of embryology?

32. Equal-sized groups carrying three heritable variants are followed through one breeding season.

Assuming the viable offspring contribute equally to the next generation, which variant shows the greatest reproductive fitness in this season?

33. Seed ferns, progymnosperms, cycads, conifers, ginkgos and gnetales are shown on different branches within a geological plant-history representation. The relationship is best interpreted as:

34. Match each evolutionary record with its description. A Column II entry is used once.

35. Industrial melanism and antibiotic resistance involve very different organisms and environmental pressures. Which causal feature is shared by both?

36. A large heritable mutation appears suddenly in one plant. During the next generations, carriers consistently leave more viable offspring and the mutation becomes common. Which explanation best integrates the events?

37. Match each lineage or group with the relationship it occupies in the described vertebrate branching history. A Column II entry is used once.

38. Region P becomes connected to a neighbouring continent, allowing extensive mammalian immigration. Region Q remains geographically isolated and retains a distinctive resident mammalian radiation. Which synthesis best fits these contrasting histories?

39. A Java fossil dated to about has a cranial capacity near , but no dietary evidence is preserved. Which conclusion remains best supported?

40. Consider the following records: primate forms around , upright East African forms around , Homo erectus around , Neanderthals tens of thousands of years ago, cave art around , and agriculture around . Which statement best integrates the sequence?

41. Which combination of the following statements about embryological evidence is valid?
I. Early vertebrate embryos may share certain structural features.
II. Shared embryonic features can contribute evidence of evolutionary relationship.
III. Every vertebrate embryo literally passes through the adult stages of its evolutionary ancestors.
IV. Similarities must be interpreted with developmental qualifications rather than as exact adult recapitulation.

42. In a finch population, heritable differences in beak form already exist. A new food source becomes abundant, and one beak form allows more efficient use of that resource. Over many generations, the most likely evolutionary outcome is:

43. A simplified plant-evolution table is given below.

Which conclusion requires the least additional assumption?

44. A population contains two heritable alleles but no individuals differ in reproductive success. Recombination generates many new genotype combinations, yet allele frequencies remain unchanged for several generations. Which conclusion is most appropriate?

45. A newly founded island population has allele R at frequency before any reproduction occurs there, whereas the mainland source population has R at frequency . No evidence shows that R affects survival or reproduction. Which inference is strongest?

46. A flowering plant population shows the sudden appearance of a large, heritable phenotypic change in one generation rather than a long series of small visible intermediates. Which historical evolutionary idea is most directly illustrated by the appearance itself?

47. A modern Homo sapiens fossil is found outside Africa within the stated interval. How should this finding be interpreted relative to African origin?

48. Arrange the following broad events in the most appropriate order.
P. Formation of a universe containing mainly hydrogen and helium
Q. Formation of galaxies and stars
R. Formation of planets including Earth
S. Chemical and later biological evolution on Earth

49. Turtles, lizards, snakes, tuataras, crocodiles and birds occupy surviving endpoints on the sauropsid side of a simplified vertebrate history, whereas mammals occupy the synapsid side. The branch information most directly implies that:

50. Consider three dates in relation to the stated Neanderthal and modern Homo sapiens intervals.

Which interpretation is correct?