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?
Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually? Why or why not?
How does the creation of variations in a species promote survival?
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?
What are the different methods of contraception?
No matter how far you stand from a mirror, your image appears erect. The mirror is likely to be
(a) only plane.
(b) only concave.
(c) only convex.
(d) either plane or convex.
A concave lens of focal length 15 cm forms an image 10 cm from the lens. How far is the object placed from the lens? Draw the ray diagram.
Can you suggest some changes in your school which would make it environment-friendly?
What does one mean by exothermic and endothermic reactions? Give examples.
What is a balanced chemical equation? Why should chemical equations be balanced?
What does an electric circuit mean?
What processes would you consider essential for maintaining life?
An electric heater of resistance 8 Ω draws 15 A from the service mains 2 hours. Calculate the rate at which heat is developed in the heater.
Metallic oxides of zinc, magnesium and copper were heated with the following metals.
Metal | Zinc | Magnesium | Copper |
---|---|---|---|
Zinc oxide | |||
Magnesium oxide | |||
Cooper oxide |
In which cases will you find displacement reactions taking place?