Why is variation beneficial to the species but not necessarily for the individual?
Variations are beneficial to the species than individual because during certain environmental conditions their is so drastic change that their survival of species becomes difficult. For example, if their is sudden rise in temperature of water, then most of the bacteria living in that water would die. So only few variants that can resistant to heat would be able to survive. However, if these few variants were not there, then the entire species of bacteria would have destroyed. Thus, these variants help in the survival of the species.So all variations are not necessarily beneficial for the individual organisms.
Draw a labelled diagram of the longitudinal section of a flower.
What are the functions performed by the testis in human beings?
Why does menstruation occur?
How will an organism be benefited if it reproduces through spores?
Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?
Asexual reproduction takes place through budding in
(a) amoeba.
(b) yeast.
(c) plasmodium.
(d) leishmania.
What are the advantages of sexual reproduction over asexual reproduction?
How does the embryo get nourishment inside the mother’s body?
How does reproduction help in providing stability to populations of species?
What is the importance of DNA copying in reproduction?
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?
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?
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 is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?
Give an example of a double displacement reaction other than the one given in activity 1.10.
Why does a compass needle get deflected when brought near a bar magnet?
What changes can you make in your habits to become more environment-friendly?
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
State the principle of an electric generator.
What can you as an individual do to reduce your consumption of the various natural resources?
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?
Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute H2SO4.
Name two elements you would expect to show chemical reactions similar to magnesium. What is the basis for your choice?