What is a key stone species ?

• A rare species that has minimal impact on biomass and on other species in community

• A dominant species that constitutes a large proportion of biomass, which affects many other species

• A common species that has plenty of biomass, yet has a fairly low impact on the community's organization

• A species which makes up only a small proportion of the total biomass of a community, yet has a huge impact on the community's organization and survival

Prototherians are the connecting links between:

• amphibians and aves

• reptiles and mammals

• fishes and amphibians

• reptiles and amphibinas

The pioneers in the field of 'organic evolution' are:

• Karl Landsteiner, Hugo de Vries, Malthus

• Darwin, Hugo de Vries, Lamarck, Huxley

• Lamarck, Karl Landsteiner, Malthus, Hugo de Vries

• Darwin, Lamarck, Karl Landsteiner, Hugo de Vries

Darwin finches are related to which of the following evidences ?

• Fossils

• Embryology

• Anatomy

• Geographical distribution

Allopatric speciation is due to :

• geographical separation of population

• hybridization between closely related species

• migration of the members of a species from one to other population

• both (b) and (c)

Evolutionary convergence is characterized by:

• development of characteristics by random mating

• replacement of common characteristic in different related groups

• development of dissimilar characteristics in closely related groups

• development of a common set of characteristics in groups of different ancestry

In which of the following population, genetic drift operates?

• Island

• Smaller

• Larger

• Continental

The driving force of an ecosystem is :

• producers

• biomass

• solar energy

• grassland

The correct match of atmospheric gases is :

• Nitrogen - 0.03%; Oxygen - 78.08%; Argon­ - 0.93%; CO₂ - 20.95%

• Nitrogen - 78.08%; Oxygen - 20.95%; Argon - 0.03%; CO₂ - 0.03%

• Nitrogen - 0.03%; Oxygen - 78.08%; Argon - 20.95%; CO₂ - 0.93%

• Nitrogen - 78.08%; Oxygen - 20.95%; Argon - 0.93%; CO₂ - 0.03%

Zooplanktons are :

• parasites

• primary producers

• primary consumers

• primary decomposers