Introduction of Nile perch (an exotic predatory fish) into lake Victoria (South Africa) threatened the entire ecosystem of the lake by eliminating several native species of the small Cichlid fish species that were endemic to this fresh water ecosystem. 

The last twenty years alone have witnessed the disappearance of 27 species. Careful analysis of records shows that extinctions across taxa are not random; some groups like amphibians appear to be more vulnerable to extinction. Adding to the grim scenario of extinctions is the fact that more than 15,500 species world-wide are facing the threat of extinction.

Gymnosperms are among the most threatened living organisms on the planet, with 40% of their species at high risk of extinction, which is about twice as many as the most recent estimates for all plants.

Those species whose number of individuals is greatly reduced recently and is decreasing continuously and are at a high risk of endangerment in the wild are known as vulnerable species. Some examples of vulnerable species are Barasingha, Nilgiri Langur, Yak, Olive Ridley Turtle, Sloth bear, etc.

In graphical forms, steeper slopes means slopes which are closer to vertical axis, or in other words they make larger angle with horizontal axis.

In case of species area relationship given by Alexander von Humboldt, steeper slopes (Z values in the range of 0.6 to 1.2) are obtained when species relationships are plotted among very large areas like the entire continents. Steeper slopes signifies that number of species found increases faster than the area explored in very large areas like the entire continents.

Rivet-Popper hypothesis was given by famous ecologist Paul Ehrlich. In this hypotheisis -Paul has thrown light on the importance of various components(like different species) of ecosystem  by comparing ecosystem with an aero plane and its components with the airplane rivets. Rivets are nothing but the various bolts which complete the design of plane &help it in flying. If passengers , travelling in the plane found those rivets useful for any of their personnel purpose and take away them then it will result in the unsafe flight and  can lead to plane crash. In the same way,  different components of ecosystem play an important role in maintaining its balance. So, humans should not disturb/use them  for their own benefits as it it ultimately result in the loss of  ecological balance.

Total number of biodiversity hotspots in the world to 34. Three of these hotspots –Western Ghats and Sri Lanka, Indo-Burma and Himalaya –cover our country ’s exceptionally high biodiversity regions.

There are 34 areas around the world which are qualified as Biodiversity hotspots. These hotspots represent only 2.3% of the total Earth 's land surface. These hotspots are important because Biodiversity underpins all life on Earth. Without species, there would be no air to breathe, no food to eat, no water to drink. There would be no human society at all. And as the places on Earth, where the most biodiversity is under the most threat, hotspots are critical to human survival.

Those species called whose members are few and live in a small geographical area and are very uncommon, scarce, or infrequently encountered are known as rare species. Some examples of rare species are Malabar Giant Squirrel, Gee ’s Golden Langur, Dugong, Indian Giant Flying Squirrel, etc.

The species called whose members are in danger of extinction but the reason is unknown, no enough information is available to decide their true nature are called indeterminate species. Some examples of intermediate species are Short-eared rabbit of Sumatra, Three-banded armadillo of Brazil, Rhinoceros, etc.