Class 10 Science Chapter 8 Question Answers - Heredity

Q1: What is evolution?
Ans: Evolution is the gradual process through which living organisms change over long periods of time, resulting in the development of new species from pre-existing ones.

Q2: Why is Charles Darwin famous?
Ans: Charles Darwin is renowned for his theory of evolution by natural selection, which explains how species change over generations to better adapt to their environments.

Q3: What is natural selection?
Ans: Natural selection is the process where organisms with advantageous traits that help them survive and reproduce pass those traits on to their offspring, gradually leading to the prevalence of those traits in a population.

Q4: How does adaptation relate to evolution?
Ans: Adaptation refers to traits that help organisms survive in their environment. Over time, these advantageous traits become more common in a population, driving the process of evolution.

Q5: What is a fossil?
Ans: Fossils are preserved remains of ancient plants and animals. They provide evidence of past life forms and how they have changed over time.

Q6: How do fossils support the theory of evolution?
Ans: Fossils offer a record of earlier life forms and show the progression of species, supporting the idea that different species have evolved from common ancestors.

Q7: What is speciation?
Ans: Speciation is the process by which new species emerge from existing ones due to accumulated differences over time.

Q8: How does geographical isolation contribute to speciation?
Ans: Geographical isolation separates populations, leading to different environmental pressures and eventually resulting in the development of distinct species.

Q9: What are homologous structures?
Ans: Homologous structures are similar body parts in different species that suggest a common ancestor. For example, the wing of a bat and the arm of a human share a common origin.

Q10: Explain the concept of 'survival of the fittest.'
Ans: Survival of the fittest means that organisms best suited to their environment are more likely to survive, reproduce, and pass on their traits, leading to the evolution of species over time.

Q11: What is genetic variation?
Ans: Genetic variation refers to the differences in genetic material among individuals of the same species, which is crucial for natural selection and evolution.

Q12: How does human intervention influence evolution?
Ans: Human activities, such as selective breeding in agriculture and animal husbandry, can accelerate certain traits' prevalence in a population, leading to rapid evolutionary changes.

Q13: What is meant by the term 'common ancestry'?
Ans: Common ancestry suggests that different species share a common origin or ancestor, and their differences have arisen over millions of years of evolution.

Q14: How does the study of DNA support the theory of evolution?
Ans: Comparing DNA sequences among different species reveals similarities that reflect their evolutionary relationships and common ancestry.

Q15: What is meant by the term 'extinction'?
Ans: Extinction occurs when a species no longer exists, often due to environmental changes or competition with other species.

Q16: Can evolution happen within a single individual's lifetime?
Ans: Evolution is a gradual process that occurs over many generations, so significant changes within a single individual's lifetime are not typical.

Q17: What role do mutations play in evolution?
Ans: Mutations are random changes in an organism's DNA. While most mutations are neutral or harmful, occasionally they lead to beneficial traits that can contribute to evolutionary change.

Q18: How does the environment influence evolution?
Ans: Environmental factors, like climate and food availability, exert pressure on organisms, driving adaptations and influencing the direction of evolution.

Q19: Why do some species evolve while others remain relatively unchanged?
Ans: Species that experience significant changes in their environment or face intense competition are more likely to undergo evolutionary adaptations, while others may remain relatively unchanged if their environment remains stable.

Q20: Is evolution a fact or a theory?
Ans: Evolution is both a fact (as evidenced by the fossil record and genetic data) and a scientific theory that explains how and why evolution occurs (such as through natural selection and genetic variation).