Ecosystems — BIOLOGY STD 12 Science — Question

Write briefly Hardy weinberg Law.

Read the following statements carefully and give a term for each of them.

1. Programmes at a national level to attain total reproductive health as a goal are called.
2. A rapid increase in population over a relatively short period is called.
3. A rapid decline in death rate is called.
4. Permanent movement of people out of an area is called.

In a cross between two tall pea plants, some of the offsprings produced were dwarf. Show with the help of Punnet square, how this is possible.

Explain the process of syngamy and double fertilization.

Explain the significant role of the genus Nucleopolyhedrovirus in an ecological sensitive area.

Write the full form of the following:

1. MMR.
2. IVF.
3. GIFT.
4. ART.

The following graph shows the species-area relationship. Answer the following questions as directed.

1. Name the naturalist who studied the kind of relationship shown in the graph. Write the observations made by him.
2. Write the situations as discovered by the ecologists when the value of Z (slope of the line) lies between (a) 0.1 and 0.2 (b) 0.6 and 1.2. What does Z stand for?
3. When would the slope of the line 'B' become steeper?

For the MN-blood group system, the frequencies of M and N alleles are 0.7 and 0.3, respectively. The expected frequency of MN-blood group bearing organisms is likely to be:

What do 'cry' genes in Bacillus thuringiensis code for? State its importance for cotton crop.

The backbone of DNA strands contains atoms joined by covalent bonds, whereas the bases between the two strands are hydrogen bonded. Based upon your knowledge of bonds, what is the significance of the type of bonding existing in a DNA molecule?