According to Robert May, the global species diversity is about [2020]
1.5 million
20 million
50 million
7 million
Which of the following is the most important for animals and plants being driven to extinction? [2019]
Alien species invasion
Habitat loss and fragmentation
Drought and floods
Economic exploitation
(2)
Habitat loss and fragmentation is the most important cause of driving the animals and plants to extinction. When large habitats are broken into small fragments due to various human activities, mammals and birds requiring large territories and certain animals with migratory habitats are badly affected, leading to population declines. The same can be applicable to the plant (forest) loss and degradation as millions of species are being cut and cleared for the expansion of agricultural land, harvesting timber, forest fire, as well as overgrazing.
Decline in the population of Indian native fishes due to introduction of Clarias gariepinus in river Yamuna can be categorised as [2019]
co-extinction
habitat fragmentation
over-exploitation
alien species invasion
Alexander von Humboldt described for the first time [2017]
laws of limiting factor
species area relationships
population growth equation
ecological biodiversity.
(2)
Alexander von Humboldt described species area relationship for the first time. He observed that within a region, species richness increases with increasing explored area, but only upto a limit.
Which of the following is correctly matched? [2016]
Aerenchyma – Opuntia
Age pyramid – Biome
Parthenium hysterophorus – Threat to biodiversity
Stratification – Population
(3)
Parthenium hysterophorus is commonly known as congress grass or carrot weed. It is herbaceous annual plant of Family Asteraceae. It is a deadly invasive, noxious weed infesting cropped and non-cropped areas. It rapidly colonises area replacing the native vegetation and causes a number of human health related problems such as skin allergy, rhinitis and eye irritations. Also, being toxic and unpalatable it causes fodder scarcity. Hence, it is considered a threat to the biodiversity.
Red list contains data or information on [2016]
all economically important plants
plants whose products are in international trade
threatened species
marine vertebrates only
(3)
A red data book or red list is a catalogue of taxa facing risk of extinction. Red data book or red list was initiated in 1963.
Which is the national aquatic animal of India? [2016]
Blue whale
Sea-horse
Gangetic shark
River dolphin
(4)
River dolphin found in holy river Ganga, Brahmaputra, Indus and its tributaries is the National aquatic animal of India. Presence of river dolphin in Ganga indicates pure and freshwater.
Which of the following is the most important cause of animals and plants being driven to extinction? [2016]
Habitat loss and fragmentation
Co-extinctions
Over-exploitation
Alien species invasion
(1)
Destruction of natural habitat causes the most serious threat to the biodiversity. Over-population, urbanisation and industrialisation lead to the destruction or fragmentation of natural habitats to fulfill the requirement of additional land. Loss of habitat results in annihilation of plants, microorganisms and forcing out of animals which in alien lands die out after some time. Fragmentation of habitats results in disruption of complex interactions amongst species, destruction of species in the cleared regions, annihilation of species restricted to deeper undisturbed parts of forests and decreased biodiversity in the habitat fragments.
A species facing extremely high risk of extinction in the immediate future is called [2014]
vulnerable
endemic
critically endangered
extinct
(3)
The taxon under critically endangered category are facing very high risk of extinction in the wild and can become extinct at any moment in the immediate future.
The organization which publishes the Red list of species is [2014]
ICFRE
IUCN
UNEP
WWF
(2)
IUCN is International Union of Conservation of Nature and Natural Resources which is now called World Conservation Union (WCU). It has its headquarters at Morges, Switzerland. It maintains a red data book or red list which is a catalogue of taxa facing risk of extinction. Red data book or red list was initiated in 1963. The Red list of year 2000 has made assessment of 18,000 species.
