Biodiversity, Conservation and Environmental Issues — BIOLOGY STD 12 Science — Question

Study the table given below and answer the questions that follow:

Species A	Species B	Name of interaction
(+)	(+)	(A)
(-)	(-)	(b)
(+)	(-)	(c)
(+)	(0)	(d)

+ = Beneficial interaction
- = Detrimental interaction
0 = Neutral interaction
Identify a, b, c and d in the given table and explain any three of them with the help of an example each.

1. List any four abiotie components that lead to variations in the physical and chemical conditions of different habitats.
2. Explain the impact of these components distribution of organisms in different habitats.

What are the major features of embryonic development at various months of pregnancy?

Write about the various theories of evolution.

Ventricles in human brain.

With the help of suitable diagram, describe the conducting system of human heart.

1. How do organic farmers control pests? Give two examples.
2. State the difference in their approach from that of conventional pest control methods.

What are hallucinogens? Give two examples. Mention their clinical use, if
any.

Species richness goes on decreasing as we move from equator to pole. Explain.

Work out a typical Mendelian dihybrid cross and state the law that he derived from it.