The main difference between "Sixth Extinction" and the previous five extinctions is that the sixth extinction:
1. is mainly occurring on islands
2. is mainly affecting plants
3. is occurring at a faster rate
4. does not involve human activities

Which of the following does not contribute to the species diversity of the tropics?

1. Predictability

2. Predation

3. High productivity

4. Spatial homogeneity

The relation between species richness and area for a wide variety of taxa on a logarithmic scale is a:

1. rectangular hyperbola

2. straight line

3. sigmoid curve

4. sine curve

The hot spots of biodiversity conservation are characterized by:
1. High endemicity and high threat of extinction
2. Low endemicity and high threat of extinction
3. High endemicity and low threat of extinction
4. Low endemicity and low threat of extinction

Which of the following has maximum global biodiversity?
1. Angiosperms
2. Algae
3. Lichens
4. Mosses

What is applicable to both Lates niloticus and Lantana camara ?

1. They are on the verge of extinction due to over-exploitation by humans.

2. They are alien species that became invasive in certain environments causing threat to indigenous biodiversity.

3. They are mutualists and likely to undergo co-extinction in recent future.

4. They are keystone species and are vital to the stability of tropical ecosystems.

Most primary productivity in the surface water of lakes and oceans is by:
1. Floating plants
2. Red and brown algae
3. Zooplankton
4. Phytoplankton

The most effective means of conservation of biodiversity is:
1. Remove predators
2. Preserve habitats
3. Vaccinate against disease
4. Census the species during breeding season

Alexander von Humbolt described for the first time 
(1) ecological biodiversity

(2) law of limiting factor

(3) species area relationships

(4) population growth equation 

Presence of plants arranged into well defined vertical layers depending on their height can be best seen in

(1) tropical savannah

(2) tropical rain forest

(3) grassland

(4) temperate forest