Microbes in Human Welfare — BIOLOGY STD 12 Science — Question

In F. Griffith's experiment, how did the non-virulent strain of Streptococcus pneumonia become virulent?

Name two microbes that are useful in biotechnology experiments.

In a dihybrid cross carried out by T.H. Morgan in Drosophila, the F, ratio deviated from that of Mendel's dihybrid F, ratio. Give a reason.
Or
Why do certain genes tend to be inherited together in a cell at the time of cell division?

Or
If the frequency of a parental form is higher than 25% in a dihybrid test cross, what does that indicate about the two genes involved?

State Gause's competitive exclusion principle.

A geneticist interested in studying variations and patterns of inheritance in living beings prefers to choose organisms for experiments with shorter life cycle. Provide a reason.

What is a monosomic condition?

List out the consequences of population explosion.

What do you understand by survival of the fittest?

How is fertilisation by a self-incompatible pollen prevented?

What is it that prevents a child to suffer from a disease he/ she is vaccinated against? Give one reason.