BIOLOGY 2 Marks Questions

Write about Gause's Competitive Exclusion principle.

Write about from a study of the history of life on earth through fossils record.

It is a common practice to plant trees and shrubs near the boundary walls are buildings. What purpose do they serve ?

Apart from plants and animals, microbes form a permanent biotic component in an ecosystem. While plants have been referred to as autotrophs and animals heterotrophs, what are microbes referred to as? How do the microbe fulfill there energy requirements ?

Explain about Commensalism.

Explain about antibiotics.

The following table shows certain diseases, their causative organisms and symptoms, fill the gaps.

	Name of the disease	Causative organism	Symtpoms
(i)	Ascariasis	Ascaris	(A)
(ii)	(B)	Trichophyton	Appearance of dry, scaly lesions on various parts of the body.
(iii)	Typhoid	(C)	High fever, weakeness, headache, stomach pain, constipation.
(iv)	Pneumonia	Streptococus pneumoniae	(D)
(v)	(e)	Rhnio viruses	Nasal congestion and discharge, sorethroat, cough, headache
(vi)	Filariasis	(f)	Inflammation in lower limbs.

During DNA replication, why is it that the entire molecule does not open in one go? Explain replication fork. What are the two functions that the monomen (dNTPs) play?

How was it concluded that genes are located on chromosomes?

What are the probable factors that contributed to population explosion in India?

Does self in compatibility impose any restrictions on autogamy ? Give reasons and suggest the method of pollination in such plants.

Give an account on viability of pollen ?