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Evolutionary History Of Rhinoceros – Free PDF Download

 

Introduction

  • A study published in August in the journal Cellhas shed light on the evolutionary history of the rhinoceros.
  • The rhinoceros family belongs to the Rhinocerotidae clade, which also includes the tapirs.
  • A clade includes species from a single common ancestor.
  • The rhinoceros family diverged from the tapir family some 55-60 million years ago.
  • The family then evolved into over a hundred species distributed across the world, but only nine of them survived to the Late Pleistocene age (14 to 12000 years ago).

  • Subsequent extinctions resulted in five extant species – the black, white, Sumatran, Indian, and Javan rhinoceroses – and four extinct ones – the Siberian, Merck, narrow-nosed and woolly rhinoceroses.
  • There are primarily three theories governing the story of rhinoceros evolution.
  • One theory, known as the ‘horn hypothesis’, emphasises horn morphology, and puts the Sumatran, the black, and the white rhinoceros species together for they have two horns.

Genomic analyses

  • The study assembled and examined genomes from eight rhinoceros species.
  • The findings lend support to the geographical hypothesis and identify three major clades for the rhinoceros family.
  • One clad comprises the black and white rhinoceros species, both from Africa. A second clade comprises Sumatran, Merck, and woolly rhinoceroses.
  • The third clade comprises the Indian and Javan species.
  • The paper asserts that “the principal divergence among the rhinoceros lineages is related to the geographical division between species on the African and Eurasian continent

Loss of genetic diversity

  • A major finding of the study, important from the point of view of conservation efforts, is that of the loss of genetic diversity in rhinoceros populations in recent years due to rapid population declines.
  • They find that present-day rhinos have lower genetic diversity, and higher levels of inbreeding, compared to our historical and prehistoric rhinoceros genomes.
  • The authors hypothesise that a land-‘bridge’ connecting Afro-Arabian and Eurasian land masses formed 20 million years ago, which ‘enabled dispersal events.’ But this was followed by the creation of geographical barriers to the movement of species, a phenomenon known as vicariance or allopatric speciation.
  • While the authors acknowledge that only a small fraction of the entire Rhinocerotinae group was studied here, they hope that genomic studies can aid the understanding of the rhino genetic history and augment efforts in population recovery

Great Indian rhinoceros

  • The Indian rhinoceros also called greater one-horned rhinoceros or great Indian rhinoceros is a rhinoceros species native to the Indian subcontinent.
  • It is the only large mammal species in Asia to be down-listed from endangered to vulnerable in the International Union for Conservation of Nature,IUCN Red list in 2008.
  • The extent and quality of the rhino’s most important habitat are considered to be in decline due to hunting, agricultural development in tarai region and livestock encroachment.
  • Indian rhinos once ranged throughout the entire stretch of the Indo-Gangetic Plain has reduced drastically to 11 sites in northern India and southern Nepal.
  • The Greater One-Horned Rhinois one among the five different species of Rhino. The other four are:
  • Black Rhino:Smaller of the two African species.
  • White Rhino:Recently, researchers have created an embryo of the northern white rhino by using In vitro Fertilization (IVF) process.
  • Javan Rhino: Critically endangeredin IUCN Red List.
  • Sumatran Rhino:Recently gone extinct in Malaysia.

DNA Database of Indian Rhino

  • By 2021, the Indian rhino could be the first wild animal species in India to have all its members DNA-sequenced.
  • The project’s proponents include the World Wildlife Fund for Nature-India (WWF-India) and the Centre-funded Wildlife Institute of India (WII).

National Rhino Conservation Strategy

  • It calls for active engagement between India and Nepal to conserve the Greater one-horned rhinoceros.

  • The plan said the single population of rhinos in Sukla-Phanta (Nepal), Valmiki Tiger Reserve (India) and Chitwan National Park (Nepal) and Dudhwa (India) is separated by the political boundary between the two countries.
  • It asks for the management of the two population under the same protocol, instead of managing the two population separately.
  • The plan calls for expanding distribution range as the occurrence of 90% of the rhino in one protected area is a cause of concernand conservation of existing and potential rhino habitats need to be made a national priority
  • On September 22nd, World Rhino Day is commemorated to raise awareness about all five rhino species and the work being done to save them.
  • The World Wildlife Fund (WWF) – South Africa was the first to announce it in 2010. The rhinoceros’ species is on the verge of extinction as a result of decades of poaching and habitat loss.

Q.Consider the following statements:

  1. It is the only large mammal species in Asia to be down-listed from endangered to vulnerable
  2. World Rhino Day is commemorated on 22nd september by United Nation

Which of the statements given above is/are correct?

(a) Both 1 and 2 are correct

(b) 1 Only

(c) 2  only

(d) Both 1 and 2 are incorrect

 

 

 

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