UPSC Daily Current Affairs | Prelim Bits 28-06-2020
iasparliament
June 28, 2020
Domestication of Chicken
A recent study by scientists has revealed new details about the earliest domestication of chicken.
The DNA sequencing of 863 genomes has showed the first domestication of chicken occurred in south-western China, northern Thailand and Myanmar.
According to Charles Darwin, chickens were domesticated around 4,000 B.C. from a single ancestor, Red Jungle Fowl in the Indus Valley.
The recent study involved sequencing of genomes from all four species of the genus Gallus, five sub-species of Red Jungle Fowl and various domestic chicken breeds collected worldwide.
It revealed single domestication from Red Jungle Fowl sub-species Gallus gallus spadiceus.
It contradicted the earlier claim that chickens were domesticated in northern China and the Indus Valley.
Covid-19 and Type-1 Diabetes
Recent findings highlights the evidence that novel coronavirus might actually be triggering diabetes in some people who have so far remained free of it.
These patients typically develop type-1 diabetes, the virus seems to be causing diabetes spontaneously in people.
Type-1 diabetes is caused when the body’s immune system begins to attack and destroy the beta cells, which produce the hormone insulin in the pancreas.
With the destruction of beta cells, the amount of insulin produced is reduced, and hence, the ability of the body to control blood sugar is compromised leading to type-1 diabetes.
The 2002 SARS coronavirus, too, caused acute-onset diabetes in patients.
Type -2 Diabetes
Type II diabetes arises when body develops insulin resistance.
Insulin is produced by the pancreas and is necessary for getting glucose from the bloodstream to cells to be used for energy.
With type II diabetes, cells do not respond as they should to the insulin, and the pancreas becomes less and less able to keep up.
When the insulin does not take glucose from the blood to cells, blood sugar levels rise.
Last Glacial Maximum
About 19,000-21,000 years ago, ice-sheets covered North America and Eurasia, and sea-levels were much lower, with Adam’s Bridge exposed so that the Indian subcontinent and Sri Lanka were contiguous.
This period, the peak of ice age conditions, is called the Last Glacial Maximum.
Global sea-level is rising and glacial ice is melting today, whereas the opposite was true for the Last Glacial Maximum.
Researchers analysed simulations of this past climate and predicted that the ongoing climate change could reawaken an ancient climate pattern of the Indian Ocean.
They find that this could be similar to the El Nino phenomenon of the Pacific Ocean bringing more frequent and devastating floods and drought to several densely-populated countries around the Indian Ocean region.
If current warming trends continue, this new Indian Ocean El Nino could emerge as early as 2050.
It could bring more frequent droughts to East Africa and southern India and increased rainfall over Indonesia.
Foraminifera
By studying microscopic zooplankton called foraminifera, the team had published a paper in 2019 which first found evidence from the past of an Indian Ocean El Niño.
Foraminifera build a calcium carbonate shell, and studying these can tell us about the properties of the water in which they lived.
The team measured multiple individual shells of foraminifera from ocean sediment cores and was able to reconstruct the sea surface temperature conditions of the past.
Assertions on South China Sea
South China Sea issue is a dispute over territory and sovereignty over ocean areas, and the Paracels and the Spratlys – two island chains claimed in whole or in part by a number of countries.
Alongside the fully fledged islands, there are dozens of rocky outcrops, atolls, sandbanks and reefs, such as the Scarborough Shoal (claimed by Philippines).
In recent times China has been pushing its presence in the Exclusive Economic Zones of other countries in South China Sea.
Beijing unilaterally declared the creation of new administrative districts on islands in the troubled waterways to which Vietnam and the Philippines also have competing claims.
Besides, the often mentioned Nine-Dash line that China uses as a basis for its claims in the waters is once again at odds with Indonesia’s claim that the line lacks an international legal basis.
