Why are traits acquired during the life-time of an individual not inherited?
Acquired traits are those, people attain during it life- time due to change in environment and on the other hand, inheritance is the transfer of characters as well as variations or information from one generation to the next by the copying of DNA. Traits are acquired during the life- time not inherited because inheritance occurs during the birth of an individual, and traits are acquired when people learn for their future and to make the changes in their work that does not affect the DNA of the germ cells, like in the inherited traits where DNA get affected by the changes. If any mutation occurs in the germ cell it can give rise to the new trait being acquired by the next successive generation.
Outline a project which aims to find the dominant coat colour in dogs.
How is the sex of the child determined in human beings?
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?
How do Mendel’s experiments show that traits are inherited independently?
If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?
Explain how sexual reproduction gives rise to more viable variations than asexual reproduction. How does this affect the evolution of those organisms that reproduce sexually?
Explain the terms analogous and homologous organs with examples.
How do Mendel’s experiments show that traits may be dominant or recessive?
How does the creation of variations in a species promote survival?
Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually? Why or why not?
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
What is a good source of energy?
Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
What changes can you make in your habits to become more environment-friendly?
What is the difference between a reflex action and walking?
What is the importance of DNA copying in reproduction?
Why should a magnesium ribbon be cleared before burning in air?
Define the principal focus of a concave mirror.
You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?
Describe the structure and functioning of nephrons.
Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.
Name a mirror that can give an erect and enlarged image of an object.
Find out, from Table 10.3, the medium having highest optical density. Also find the medium with lowest optical density.
Material medium |
Refractive index |
Material medium |
Refractive index |
Air | 1.0003 | Canada Balsam |
1.53 |
Ice | 1.31 | ||
Water | 1.33 | Rock salt | 1.54 |
Alcohol | 1.36 | ||
Kerosene | 1.44 | Carbon disulphide |
1.63 |
Fused quartz |
1.46 | ||
Turpentine oil |
1.47 | Ruby | 1.71 |
Benzene | 1.50 | Sapphire | 1.77 |
Crown glass |
1.52 | Diamond | 2.42 |
Table 10.3 Absolute refractive index of some material media
Can any source of energy be pollution-free? Why or why not?
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
What is the role of the acid in our stomach?
What are the components of the transport system in human beings? What are the functions of these components?
How do auxins promote the growth of a tendril around a support?
Give an example of a double displacement reaction other than the one given in activity 1.10.