Describe the mechanism that determines the sex of a child | Homework Helpers

Answer in a word or sentence:

1. Who gave the theory of natural selection and the concept of ‘organic evolution’?

2. What idea is proposed by J.B.S Haldane about the origin of life on earth?

3. Give an example where environmental factors play a major role in sex determination.

4. What is the requirement if a change has to be inherited?

5. What is the basic most common characteristic of all animals, plants and humans?

6. Name an organism that has rudimentary eyes?

7. What kind of characteristics is considered helpful in tracing the evolutionary relationships among species?

8. Who was the first person to devise the principles of inheritance?

9. Give an example of homologous organs?

10. Fossil remains of which organism shows characteristics of both birds and reptiles?

Answer the following:

1. Describe the mechanism that determines the sex of a child.

2. Explain the concept of acquired trait with the help of an example?

3. Explain the theory of natural selection given by Darwin?

4. Mention the contribution of Lamarck in understanding the concept of evolution?

5. Explain the meaning of term speciation? Mention its significance also?

6. What will happen if due to some accident changes occur in the gene frequency of members of sub population of a species? Also identify the name of this phenomenon?

7. Mention some of the tools for tracing evolutionary relationships among species?

8. Define the term “characteristics”. Why study of characteristics of species is considered helpful?

9. What do you understand from tissue level of organization?

10. How can it be said that birds are closely related to reptiles?

11. “A brother and sister are more related to each other as compared to the case when any one of them is related with his/her cousin.”  Through this statement what will we get to know about their ancestors?

12. Describe briefly the origin of earliest members of human species and how they were spread in different parts?

13. Why it is more appropriate to compare the process of evolution with branches of a tree rather than with a laIDer?

14. Why Mendel chose pea plant for his experiments? Mention any two reasons.

15. Mention any two advantages of variation in individuals?

16. What do you mean by the term “variation”?

17. What is a monohybrid cross?

18. In Mendel’s experiments what is the meaning of term dominance?

19. What will happen when a pea plant with violet flowers is cross bred with pea plant having white flowers?

20. What will happen if F1 generation obtained in monohybrid cross is self pollinated? Explain with the help of an example.

21. On the basis of Mendel’s experiments what are factors and their significance?

22. Describe the law of independent assortment with the help of an example.

23. What are fossils? What is the significance of studying fossil records?

24. What do you mean by the term evolution?

25. Group the following given organs in three divisions; homologous organs, analogous organs and vestigial organs respectively.

26. What are the two ways by which we can find out the age of a fossil?

27. Explain the term analogous organs with the help of an example.

28. Describe the biogenetic law?

29. What are the evidences that can be used to study organic evolution?

30. A man with blood group A marries a woman with blood group O and their daughter has blood group O. Is this information enough to tell you which of the traits ? blood group A or O ? is dominant? Why or why not?