Evolution — BIOLOGY STD 12 Science — Question

Define decomposition. Write the difference between grazing food chain and detritus food chain. Make a pyramid of biomass.

Differentiate between in situ and ex situ approaches of conserving biodiversity.

Mention the role of the following in E.coli cloning vector pBR 322.

1. Selectable marker.
2. ori.
3. rop.

The basal parts of the endometrium remain intact during menstruation. Give reason.

Mark the odd one the following groups.
Rete testis, Vasa efferentia, Epididymis, Ampulla.

In the figure, structure of an antibody molecule is shown. Name the parts A, B and C.

Show A, B and C in the diagram.

Rahul introduced Ronit to his uncle and told him that Ronit is pursuing a course in biotechnology in America.
His uncle had never heard of this term earlier and was curious to know about this term. Ronit pointed towards a big tree at the base of which were present numerous tumour-like structures and said that this is the example of natural biotechnology:

1. What is biotechnology?
2. How these crown gall tumours are formed?
3. What are the values shown by Rahul's uncle?

Plasmodium falciparum is the causative agent of the most severe form of malaria. It is distributed throughout the tropics. Explain why malaria is restricted to the tropics?

Differentiate the following and give examples:
Active and passive immunity.

Excessive and continuous use of pesticides has resulted in evolution of some new species of pests. Explain what must have led to this. What is this type of evolution called?

OR

Anthropogenic action can hasten evolution. Explain with the help of a suitable example.