Science
Heredity and Evolution
आनुवंशिकता और विकास
This Class 10 Science topic from the chapter “World of Living” explains how traits are passed from parents to offspring through genes and chromosomes. Students explore Mendel’s experiments, dominant and recessive traits, inherited variation, and the basic idea of sex determination in humans. The topic also introduces evolution, showing how variations, natural selection, fossils, and similarities or differences among organisms help us understand the gradual development of life over generations.
Practice questions
Which feature of gametes is necessary to keep the chromosome number normal after fertilisation?MediumLevel 19If gametes do not provide half the chromosome number in every generation, what will be the biggest long-term problem?MediumLevel 19Even if only the tall trait appears in the first generation, why can the dwarf trait not be considered destroyed?MediumLevel 19If a plant appears tall but also carries information for dwarfness, how can a dwarf plant appear among its offspring?MediumLevel 19Appearance of a recessive trait proves what?MediumLevel 19Why is it not enough to merely memorise 9:3:3:1 in a dihybrid cross?HardLevel 19Why can it be wrong to treat acquired traits as a permanent basis of evolution?MediumLevel 19What is the most correct genetic reason why an athlete’s strong muscles do not pass directly to offspring?MediumLevel 19In natural selection, the usefulness of a trait depends on what?MediumLevel 19If a trait helps survival but does not pass to offspring, why will its contribution to evolution remain limited?MediumLevel 19Why is better survival of green insects on green leaves an example of natural selection?MediumLevel 19What is the best basis for distinguishing natural selection from genetic drift?HardLevel 19Why can genetic drift have a strong effect in a small population?HardLevel 19Despite their incomplete availability, why are fossils considered evidence of evolution?MediumLevel 19What general conclusion can be made about the relative age of a fossil found in a deeper rock layer?MediumLevel 19Why are homologous organs considered evidence of evolution even when their functions differ?MediumLevel 19What is the main evolutionary indication when comparing the human hand and a bat wing?MediumLevel 19What caution do analogous organs teach us in the study of evolution?HardLevel 19What is the strongest basis for considering a bird wing and an insect wing analogous?MediumLevel 19How can geographical isolation start the process of speciation?ExpertLevel 19