Category Science

Which is the largest animal on Earth?

Blue whales are the biggest animals that have ever inhabited our planet. These marine mammals grow up to 22 metres in length and to a weight of 150,000 kilograms. Their tongues alone weigh as much as an elephant in some cases and their hearts can be as big as an automobile.

The most interesting detail about these huge creatures is the fact that they reach these immense body sizes by consuming tiny shrimp-like animals called krills alone. In some seasons, a single adult blue whale eats about 4000 kilograms of krill a day.

Blue whales belong to the family of baleen whales. Baleen is a fringed plate made of fingernail-like material that is attached to their upper jaws. These giant animals feed by first gulping a great amount of water through their mouth and then they expand the pleated skin on their throat and belly to take it in. After this, the whales use their massive tongue and force the water out through the thin, overlapping baleen plates. This process leaves behind a large volume of krill, which gets consumed by the whales. Blue whales are found in all the oceans, except the Arctic. They occasionally swim in small groups but they move about in pairs or stay alone.

They now face a severe threat due to whaling and are considered endangered according to the IUCN Red List.

Picture Credit : Google

Birds with an aesthetic sense?

Did you know that bowerbirds are famous for building elaborate structures and even decorating them? Read on to know fascinating facts about the species.

The early European explorers to Australia and New Guinea thought that the elaborate structures they sometimes came across in the forests were built by Aborigines, so artistic and skilled were they. Imagine their surprise when they found that a species of bird was responsible!

The bird is called a bowerbird because of its habit of making complicated ‘bowers’ or places of courtship to attract and impress the females. The males spend weeks setting up and decorating their bowers. A young male may take several years to perfect the technique.

There are 20 species of bowerbirds of which the satin bowerbird of Australia builds the most elaborate bower. The remarkable structure it builds may reach up to 2.7 m in height. It may consist of a tower of twigs arranged around a central sapling or resemble a miniature house, complete with a door and thatched roof!

Other species clear an area in the forest and set up an ‘avenue’ or domed tunnel of sticks with just enough space for the bird to enter. Some prepare a lek or display area spread with upturned leaves or ’tiled’ with rocks.

Several species give their bowers a coat of paint, using charcoal mixed with saliva or the natural pigment contained in the juice of wild berries. A piece of bark fibre or a tuft of leaves held in the beak serves as a ‘paintbrush’. Not content with this, a bowerbird may bring coloured stones, feathers, leaves and flowers to add to the decoration. Iridescent insect skeletons, spider webs and snail shells serve as extra adornment.

Modern-day bowerbirds use discarded buttons, toys, empty tins, coloured straws, broken glass, and even CDs for this purpose! The floor of the bower is often strewn with an enticing bed of soft, fresh leaves.

When the male bowerbird is satisfied with his handiwork, he lures the female inside by calling loudly and when she shows interest, with a dance display. Most male bowerbirds play no part in raising the young. The female lays eggs, which she will incubate by herself. She also cares for the brood on her own.

Quick facts

  • There are 20 different bowerbird species, and the males come in colours ranging from green, orange, red, yellow and black to white, olive-brown and sooty grey. Some have a brilliant crest or a ruff. Females are comparatively dull
  • Bowerbirds live in tropical forests, mangroves, eucalyptus groves and savanna woodlands.
  • They can imitate the calls of other species, as also machines like a chain saw.
  • Satin bowerbirds may reuse and refurbish the same bower for more than 30 years.
  • Different species go for different colours. The striped gardener bowerbird prefers yellow, red, and blue objects, while the fawn-breasted bowerbird favours green
  • Bowerbirds may kill insects solely for the purpose of decorating Competition for females is fierce.
  • The birds fight for choicest pieces, steal baubles from each other and tear apart their rivals’ bowers.
  • Researchers think that they are the only animal species besides humans to have an aesthetic sense.

Picture Credit : Google 

How can we fight climate change and stop the collapse of ecosystems?

 The UN Decade on Ecosystem Restoration that runs till 2030 calls for urgent action through a global mission. Here’s an outline of the agenda and how students can get involved in fostering the recovery of ecosystems.

The Decade

As we know, our planet is plagued by several issues, most of them triggered or worsened by human activity. And how do we resolve these issues? Since the problem is not linear, neither is the solution. But one aspect that’s crucial to restoring the health of our planet is its varied ecosystems. And that’s exactly what the UN Decade on Ecosystem Restoration (2021- 2030) focusses on. This decade is contiguous with the United Nations Decade on Biodiversity from 2011 -2020, which aimed at bringing down biodiversity loss. The ongoing decade hopes to bring countries together “to prevent halt and reverse the degradation of ecosystems on every continent and in every ocean.”

Triple environmental emergency

When the restoration decade was launched virtually last year, UN Secretary-General Antonio Guterres cautioned us that by destroying our ecosystems, we “are reaching the point of no return for the planet.” But there’s still hope if we act now. And to improve the dismal situation it is imperative to at once begin addressing the triple environmental emergency – biodiversity loss, climate disruption, and escalating pollution. UN. agencies have said. “An area of land roughly the size of China needs restoring if the planet’s biodiversity and the communities who rely on it are to be protected.” So, what type of ecosystems are to be restored? All types! From farmlands, forests, freshwater, grasslands, and shrublands to savannahs, mountains, oceans, coasts, peatlands, and urban areas, all are focus areas. And when ecosystems are restored, they “can help to end combat climate change and prevent a mass extinction” For that to happen, each of us has a role to play.

How can the goal be realised?

The key to realising the goals is working together as a community at the global level. Looking at the type of local ecosystems, identifying, understanding, and adopting specific principles suitable for the restoration of each kind of ecosystem, and implementing them are crucial steps. Equally important is to have the insight that any impact one ecosystem can have a bearing on another, and to plan and execute initiatives accordingly. For instance, the restoration effort for forest and trees could involve planting of saplings while for rivers and lakes, it could be cleaning up the trash and adopting sustainable fishing practices. In towns and cities, the focus could be on starting off with small areas and steps such as setting up parks, adopting a tree, conducting awareness campaigns, etc. However, the most significant action will be an individual’s to make Earth-friendly choices in how we live. Does “Eat Right Live Light sound about right?

What can students do?

The United Nations suggests three important ways in which anyone can work towards the goal of ecosystem restoration. And these are something students can adopt too since it’s for their future.

Actions: Start your own on-the-ground initiative, join an existing restoration or conservation effort. or help build an alliance to give a bigger boost to nature’s comeback.

Choices: Change your behaviour and spending to shrink your local and global environmental footprint… Encourage others around you to do the same. Voices: Make your voice and ideas count in debates how to manage your local environment, and about how we can make our societies… fairer and more sustainable.

Picture Credit : Google 

Do air conditioners make it warmer outside?

Yes, an air conditioner takes the warm air from inside a room and transfers it outside.

An AC unit takes the warm air from inside a room and transfers it outside. It also consumes electricity which generates further heat.

A Japanese scientist found in 2007 that air conditioners in Tokyo raised the temperature in the city by about 1°C. Surprisingly, the heating effect was more at night than during the day when more air conditioners were used.

This is because the planetary-boundary layer, the part of the atmosphere touching Earth’s surface, is thickest during the day. The extra heat produced by ACS disperses upwards. At night, the same layer reduces from a thickness of 3 km to less than 100 metres! So the heat remains closer to the Earth’s surface.

Researchers feel the excess heat could be channelled through the city’s waste water pipes, since water can dissipate four times as much heat energy as air. This would reduce the heat on the street.

Picture Credit : Google 

How do we know that humpback whales communicate through songs, or about the sounds that pervade the ocean depths?

How do scientists know that humpback whales communicate through songs? That’s because they have ears placed on the bottom of the ocean at strategic points! These ‘ears’ are part of a network of underwater microphones or hydrophones placed by various scientific research organisations that eavesdrop on the sounds that pervade the inky depths-from the squeaky whistles and moans of whales and the rumbling of earthquakes, to the drone of ships passing overhead.

The sounds provide a lot of information about the world beneath the waves. The information can reveal how man-made noise affects the creatures of the deep as well as predict if the movement of tectonic plates is going to cause an earthquake.

Sound travels much further than any other form of energy in the ocean, with low-frequency sound reaching thousands of kilometres deep. Data collected from hydrophones shows that shipping activity cripples communication between whales and other marine mammals that use sound and echolocation to find their mates, fellows, and prey. The noise from ships is so loud that these animals are forced to ‘shout to be heard! According to a diver, the disturbance caused by a ship passing above is like being hit in the chest with a heavy golf club.

Data collected from hydrophones shows that shipping activity cripples communication between whales and other marine mammals that use sound and echolocation to find their mates, fellows, and prey.

Picture Credit : Google 

What conditions could help more parts of Earth host life?

Researchers find out an often overlooked key role played by the orbit of Jupiter on Earth.

Most planets have eccentric orbits. While circular orbits around a star would ensure that the distance between the star and the planet never changes, these eccentric orbits mean that the planets traverse around a star in an oval-shape. As a result, the planet would receive more heat when it goes closer to the star, affecting the planet’s climate.

Alternative solar system

Based on this knowledge and using detailed data from the solar system as we know it today, researchers from the University of California Riverside created an alternative solar system. In this hypothetical theoretical system, they were able to show that if Jupiter’s orbit were to become more eccentric, then it would lead to big changes in Earth’s orbit, thereby making the Earth more hospitable than it is currently.

This is because Jupiter in this theoretical system would push Earth’s orbit to be even more eccentric. As a result, parts of Earth would sometimes get closer to the sun. This would mean that even parts of Earth’s surface that are now sub-freezing will get warmer. In effect, the habitable range on the surface of the Earth would be increased.

Assumptions proven wrong

 The findings of this research, published in September in Astronomical Journal, go against two long-held scientific beliefs with respect to our solar system. One of these is that the current avatar of Earth is the best in terms of habitability. The second one is that changes to Jupiter’s orbit could only be bad for Earth.

Apart from upending these long-held assumptions, the researchers are looking to apply their findings in the search of exoplanets – habitable planets around other stars. While existing telescopes are adept at measuring a planet’s orbit, the same cannot be said about measuring a planet’s tilt towards or away from a star- another factor that could affect habitability.

The model developed in this research helps us better understand the impact of the biggest planet in our solar system, Jupiter, on Earth’s climate through time. Additionally, it also paves the way to find out how the movement of a giant planet is crucial in making predictions about habitability of planets in other systems.

Picture Credit : Google