The Living World

Species are considered as

1. real basic units of classification
2. the lowest units of classification
3. artificial concept of human mind which cannot be defined in absolute terms
4. real units of classification devised by taxonomists.

Biosystematics aims at

1. the classification of organisms based on broad morphological characters
2. delimiting various taxa of organisms and establishing their relationships
3. the classification of organisms based on their evolutionary history and establishing their phylogeny on the totality of various parameters from all fields of studies
4. identification and arrangement of organisms on the basis of their cytological characteristics.

Nicotiana sylvestris flowers only during long days and N. tabacum flowers only during short days. If raised in the laboratory under different photoperiods, they can be induced to flower at the same time and can be cross-fertilized to produce self-fertile offspring. What is the best reason for considering N. sylvestris and N. tabacum to be separate species?

1. They cannot interbreed in nature
2. They are reproductively distinct
3. They are physiologically distinct
4. They are morphologically distinct

What is true for individuals of same species ?

1. Live in same habitat
2. Live in different habitat
3. Interbreeding
4. Live in same niche

Which of the following is less general in characters as compared to genus?

1. Species
2. Division
3. Class
4. Family