Category Social Sciences

WHY IS THE ARCTIC AND ANTARCTICA ARE DIFFERENT?

Any mention of our polar regions – the Arctic and Antarctica – perhaps conjures up images of floating icebergs and blindingly white ice sheets. Sure, that’s common to them but they are also different from each other in many ways.

The Arctic: A variety of landscapes and animals

Home to the North Pole, the Arctic lies in the Northern Hemisphere, and is the northernmost region of Earth. The Arctic usually refers to the area within the Arctic Circle, and spans the Arctic Ocean and parts of Scandinavia, Russia, Canada, Greenland, and Alaska (a U.S. State). It is not always covered in ice, and comprises mountains, rivers, lakes, hills, etc. It hosts several types of land animals and vegetation.

Antarctica: Just ice cover and barely any land animal

Our planet’s southernmost continent, Antarctica is where the South Pole is situated. It is almost entirely covered in ice, and hardly has any vegetation or large rivers or lakes to boast of. With barely any land animals, the largest creature to dwell on land is a wingless insect that’s about half an inch. There are hardly any trees there but Antarctica has its share of lichens, moss, algae, etc.

No penguins in the Arctic

Considering videos show glistening penguins diving into the water and launching themselves back on to ice-covered land adorably, it is easy to imagine that they inhabit both the polar regions. However, these flightless birds are found only in the Southern Hemisphere, and predominantly in Antarctica. None in the Arctic!

No polar bears in Antarctica

It is called a polar bear, after all, but the name is slightly misleading. It is an animal that lives in just one polar region – the Arctic. So, there are none in Antarctica. And, the next time someone asks you if polar bears hunt penguins in the wild, you can confidently tell them that can never happen because the two never get to meet each other!

A continent without permanent residents

Only a country can have permanent residents. And since Antarctica, though a continent, has no country, it has no permanent residents. It is not home to any indigenous community either. That does not mean Antarctica has just tourists. It hosts researchers and scientists at research stations set up by many countries for experiments, especially in summer. In winter, the numbers dwindle. Hard to imagine people queuing up to be a resident in a place with punishing temperatures! On the other hand, the Arctic does host permanent residents, especially indigenous groups, since it spans several countries. In fact, it has been inhabited for thousands of years.

Summers and winters

Due to the way our planet is tilted, the poles receive less light and heat from the sun than other regions of the world. The two seasons- summer and winter – are unique. Both the polar regions have long and cold winters and short summers. During summer, the poles have daylight since the sun does not set, and in winter, it is dark since the sun does not rise. However, since the Arctic and Antarctica are in the opposite directions, when one region experiences summer, the other experiences winter, and vice-versa.

Picture Credit : Google 

Where can we find a boomslang?

‘Boomslang’ literally means ‘tree snake’, in Afrikaans and Dutch. As the name suggests, the boomslang snakes prefer to live in areas with trees wooded grasslands, arid savannas, lowland forests, etc. They are found in sub-Saharan Africa, mainly in Botswana, Swaziland, Namibia, Mozambique and Zimbabwe. They live on the trees and are active during the day. Extremely agile, they are very adept at climbing trees and gliding through the branches while hunting. The boomslang is a very dangerous, venomous snake. When the weather gets too cold, they take long, deep sleeps inside enclosed bird-nests.

The boomslangs can be of different colours, though most have a bright green colour.

Picture Credit : Google

WHICH VILLAGE IS KNOWN AS GREEN VILLAGE IN NAGALAND?

Khonoma in Nagaland is India’s first “green village”. The terrain of the village is hilly, ranging from gentle slopes to steep and rugged hillsides. The hills are covered with lush forestland, rich in various species of flora and fauna. The state bird, Blyth’s tragopan, a pheasant now nationally endangered, is found here. Khonoma is a medium size village located in Sechü Zubza sub-division of Kohima district, Nagaland with total 424 families residing. The Khonoma village has population of 1943 of which 919 are males while 1024 are females as per Population Census 2011. The village is divided into three Thinuos, namely Merhüma (M-Khel), Semoma (S-Khel) and Thevoma (T-Khel).

Khonoma village has higher literacy rate compared to Nagaland. In 2011, literacy rate of Khonoma village was 83.41 % compared to 79.55 % of Nagaland. In Khonoma Male literacy stands at 93.72 % while female literacy rate was 74.19 %. As per constitution of India and Panchyati Raaj Act, Khonoma village is administrated by Sarpanch (Head of Village) who is elected representative of village.

In 1998 hunting was banned in Khonoma’s forests after the killing of around 300 endangered Blyth’s tragopan (Tragopan blythii) in a week as part of a hunting competition. Villagers were sensitized and educated, leading to the creation of the 20 sq km Khonoma Nature Conservation and Tragopan Sanctuary (KNCTS), the first-ever community-led conservation project in India. Hunters were recruited to serve as forest wardens with a good salary, an incentive to turn from hunting to conservation. Today, the sanctuary provides a safe haven for Blyth’s tragopan, the state bird of Nagaland, and other vulnerable species such as the leopard, clouded leopard and Asiatic black bear. Conservation of Khonoma’s natural resources combined with sustainable agricultural practices led to it earning its green title in 2005.

Credit : Wikipedia 

Picture Credit : Google 

WHICH FOSSIL CONNECTS ALL THE SOUTHERN CONTINENTS?

Fossil remains of the fern Glossopteris are found in Australia, Antarctica, India, Africa and South America.

Wegener found fossil evidence that the continents were once joined. The same type of plant and animal fossils are found on continents that are now widely separated. These organisms would not have been able to travel across the oceans. So how did the fossils get so far apart?

Fossils of the seed fern Glossopteris are found across all of the southern continents. These seeds are too heavy to be carried across the ocean by wind. Mesosaurus fossils are found in South America and South Africa. Mesosaurus could swim, but only in fresh water. Cynognathus and Lystrosaurus were reptiles that lived on land. Both of these animals were unable to swim at all. Their fossils have been found across South America, Africa, India, and Antarctica.

Wegener thought that all of these organisms must have lived side by side. The lands later moved apart so that the fossils are separated.

Credit: ck12

Picture Credit : Google

WHAT IS EVOLUTION?

Life has existed on Earth for millions of years. Living forms and creatures have inhabited almost all of Earth and over the years have changed and transformed from the way they existed many years ago. This transformation and modification in features and functions in living beings is called evolution – though it is believed that a few creatures, like the modern cockroach and the crocodile, have not changed since the era of dinosaurs.

Evolution is a process that results in changes in the genetic material of a population over time. Evolution reflects the adaptations of organisms to their changing environments and can result in altered genes, novel traits, and new species. Evolutionary processes depend on both changes in genetic variability and changes in allele frequencies over time.

The study of evolution can be performed on different scales. Microevolution reflects changes in DNA sequences and allele frequencies within a species over time. These changes may be due to mutations, which can introduce new alleles into a population. In addition, new alleles can be introduced in a population by gene flow, which occurs during breeding between two populations that carry unique alleles. In contrast with microevolution, macroevolution reflects large-scale changes at the species level, which result from the accumulation of numerous small changes on the micro-evolutionary scale. An example of macroevolution is the evolution of a new species.

One mechanism that drives evolution is natural selection, which is a process that increases the frequency of advantageous alleles in a population. Natural selection results in organisms that are more likely to survive and reproduce. Another driving force behind evolution is genetic drift, which describes random fluctuations in allele frequencies in a population. Eventually, genetic drift can cause a subpopulation to become genetically distinct from its original population. Indeed, over a long period of time, genetic drift and the accumulation of other genetic changes can result in speciation, which is the evolution of a new species.

Credit: Scitable by nature education

Picture Credit: Quanta Magazine

HOW DO WE KNOW THE AGE OF A FOSSIL?

The age of a fossil is gauged by what is called radiometric, carbon-14 dating, which measures changes in its atomic structure. But carbon-14 cannot date fossils older than 50,000 years, such as those of dinosaurs. To date such fossils, other types of radiometric dating are used that calculate the age of the rocks above and below the sedimentary rock in which such a fossil was found.

When examining remnants from the past, experts use radiometric dating, a versatile technique that involves counting radioactive atoms of certain elements that are still present in a sample. The particular elements studied, as well as the details of the process, depend on the approximate age of the object that scientists hope to date.

For human or animal remains and artifacts from the past 50,000 years or so, researchers look at levels of carbon 14 in the sample. Also called “radiocarbon,” this isotope is generated by cosmic rays colliding with nitrogen in Earth’s atmosphere, says José Capriles, an archaeologist at Pennsylvania State University. Chemically, carbon 14 behaves exactly like its stable siblings (carbon 12 and carbon 13), allowing plants to absorb it during photosynthesis and then pass it up the food chain. While alive, animals and plants tend to contain the same levels of carbon 14 as their environment. But “as living organisms die, they stop consuming or incorporating radiocarbon,” Capriles says, and “the process of radioactivity kicks in,” with the isotope decaying back into nitrogen. So researchers compare the amount of carbon 14 with the levels of carbon 12 and carbon 13 to determine how much time has passed since an organism perished.

Credit: Scientific American

Picture Credit : Google