Category Science

What has caused the decline in grey whale numbers?

Often, conservation stories underline the importance of the role of all creatures-big and small-for balance in ecosystem. For instance, krill crustaceans barely two inches long are a huge link in the global food chain. If such a small organism can have a telling impact on the food chain, one can only imagine the kind of effect larger animals have in an ecosystem. So, when the population of a large animal plunges, it is always a cause for concern.

Grey whales are among the largest animals on Earth- nearly 50 feet long and weighing over 40 tonnes. These giants are known for their long annual migration of more than 15,000 km “between feeding grounds in the Arctic and breeding grounds in Baja Mexico” Recent research has revealed that the number of these fascinating creatures is witnessing a worrying slump- by nearly 40% in just six years. From 27,000 whales in 2016, the number stands at a concerning 16,650 today. Several factors are attributed to this decrease. One of them is the increase in strandings in 2019, when about 600 of these creatures washed up dead along the west coast of North America Though boat collisions and killer whale attacks caused a few of these deaths most of the dead whales were malnourished which takes us to n crucial of interconnectedness in an ecosystem. It is believed that the malnourishment could be the result of “the whales’ food sources of tiny crustaceans and other invertebrates they prey on in the Arctic shifting due to environmental changes. Further, the overall population among West Coast grey whales “coincides with diminished reproduction” While there were 383 baby whales during the calf production season last year, there have been a mere 217 newborns this year – “the lowest number since such counts began in 1994”

Grey whales were close to extinction several decades ago due to commercial whaling before their population improved due to timely conservation efforts. Even then, the 80s and 90s saw a plunge of about 40%, and eventually they rebounded. It is important for this whale population to recover too because they keep the population of certain other creatures in the food chain in check. Even in death-as carcasses- these large marine mammals help feed several other organisms.

Often, grey whales are washed up dead along the U.S. west coasts. Though boat collisions and killer whale attacks cause some deaths, researchers say malnourishment is a major reason. With tiny crustaceans and other invertebrates shifting due to environmental changes, the grey whales are left without food.

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Which is the world’s tallest tree?

The Coast Redwoods (Sequoia sempervirens) are the tallest trees on Earth. They are found along the coastline of the Redwood National Park in Northern California. Apart from being the tallest trees on the planet, they are also some of the oldest living things on Earth. They have a life of up to 2,000 years. Even though it is not clear exactly why these trees can live to be so ancient, we do know that climatic conditions play a key role in this. They are also some of the most resilient trees on Earth. Their tannin-rich bark seems to be impenetrable to the fungus and diseases that affect other trees.

According to the Guinness Book of World Records, the king of these giants is a tree known as Hyperion. When it was last measured in 2019, it stood 116.07 metres tall from top to base, taller than a 35-storey building. Hyperion’s exact location is a closely held secret, but it is known to be found in a hillside in which most of the old-growth coastal redwoods have been logged. Hyperion is estimated to be between 600 and 800 years old.

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Which is the tallest animal?

Giraffes are the world’s tallest animals with legs as long as 1.8 metres. They not only have long legs, but also have long necks that they use to reach leaves and buds on treetops, which no other animal can reach. They have very long tongues as well, which can be as long as 53.34 centimetres.

Living in the African savannah, they move at a speed of 16 kilometres per hour to cover long distances and can run as fast as 56 kilometres per hour in short distances. Although their massive height becomes advantageous while looking out for predators, it also becomes a difficulty while they drink from water holes. With their towering legs, the only way to drink water from these water holes is to bend down in a weird position that makes them vulnerable to attack. The wild cats of Africa are the most common predators of the giraffes.

Their favourite food is Acacia leaves. Like the cows, they regurgitate their food and chew it as cud. Their diet also keeps them hydrated, as the leaves have a lot of water content in them and helps them to avoid going to the water holes frequently. They also travel really long distances to find their meal as they consume about a hundred pounds of leaves every week, which is a big volume of plant matter to be found in one area.

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What animals are the masters of camouflage?

Scorpionfish

Scorpionfish, one of the most venomous fish in the world, are found across the world in warm waters. They are most common in the Indian and Pacific Oceans. They are also known as rockfish and stonefish as they commonly live among rocks. They are perch-like fish with large, spiny heads and strong, sometimes venomous. fin spines. While their spines protect them from predators, it is their colouring that helps them in hiding. They are carnivorous and generally sedentary. The fin spines, even ones without venom, can inflict deep, painful wounds. While some are dull in colour, others are brighter, often some shade of red. The largest members of the family grow about 39 inches long.

Walkingstick

Suddenly seeing a twig crawling down a tree trunk? It isn’t a twig but a walkingstick, also called stick insect. The stick-like trickster uses its appearance to save itself from enemies. They are commonly found in tropical and temperate (or mild) forests across the world. Though related to grasshoppers, crickets, and mantises, these crawlies are either brown, green, or black. They’re also the world’s longest insects. The largest one found was 22 inches long with its legs extended. They spend most of their time on trees, munching on leaves. When predators like birds approach, the bug tries to remain still to blend with the branches. However, if the predator manages to catch the bug by its legs, the insect can detach the leg and scuttle away. The leg will later regenerate, or grow back.

Camouflage

Also known as cryptic colouration, is a defence mechanism used by organisms to disguise their appearence, usually to blend/ in with their surroundings. This tactic is used to mask their location, identity and even movement. This helps the prey to protect themselves from predators.

Chameleon

Chameleons have the ability to change their colour and pattern. They are found in warm climates and in parts of the Middle East, southwestern Asia, and southern Europe, Madagascar nearly all of Africa, and parts of India and Sri Lanka. There are more than 200 species of chameleons, of which 76 are found on the island of Madagascar. Their diet consists of insects and plants, though some may eat rodents or small birds. They live in a range of habitats, including deserts, rainforests, and savannahs. The word chameleon comes from the Greek ‘khamai’ meaning on the ground, earth and leon’ meaning ‘lion’. probably because the head of some species resembles a lion’s mane. The distinctive features of these lizards are their telescopic eyes, grasping tail, colour-changing skin, and projectile tongue.

Great Potoo

The Great Potoo is a nocturnal bird of the American tropics. Its name is similar to its wailing cry, “po-TOO,” made by some species. Their patterns of grey, black, and brown plumage resemble tree bark. Their camouflage helps them to even sleep while perched out in the open during daylight During the day, the birds sleep, vertically perched and virtually indistinguishable from the dead branches they roost on They wake up at dusk with their huge, wide-open eyes capable of spotting moths and other flying insects in the dark. They are mainly solitary creatures and highly restricted nesters. Instead of building a nest, they choose a branch or stub with a crevice just enough to accommodate the single egg they lay.

Nightjar

Nightjar is a medium-sized bird that are mostly active at night feeding on flying insects. They have a protective colouring of grey, brown, or reddish brown. There are about 60 to 70 species of nightjars. They are found almost worldwide in temperate to tropical regions, except for New Zealand and some islands of Oceania. They do not make nests, instead deposit their eggs on the ground or on the leaf-covered floor of the woodland. Some of the species, mainly the North American nighthawks, have adapted to urban life and nest on flat gravel-covered rooftops. The nightjar’s soft plumage and variegated colouring help it blend in with its surroundings. Despite their skill at camouflage, some nightjar species are endangered.

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Is our world undergoing the sixth mass extinction?

There’s proof we are increasingly losing species, and this is not good for us humans

What is mass extinction?

To be classified as a mass extinction, at least 75 % of all the species on Earth must go extinct within a short geological period of less than 2.8 million years. That timeframe seems long to us because modern humans have only existed for about 2,00,000 years so far.

Mass extinction is not new

Extinctions and speciations (species evolving over time) do not happen at uniform rates through time; instead, they tend to occur in large pulses interspersed by long periods of relative stability. These extinction pulses are what scientists refer to as mass extinction events. The Cambrian explosion was a burst of speciation some 540 million years ago. Since then, at least five mass extinction events have been identified in the fossil record (and probably scores of smaller ones). Arguably the most infamous of these was when a giant asteroid smashed into Earth about 66 million years ago in what is now the Gulf of Mexico. The collision vapourised species immediately within the blast zone. Species were killed off later by resultant climate change and volcanic activity too.

Are humans responsible for the current crisis?

Humans have been implicated in smaller extinction events going back to the late Pleistocene (around 50,000 years ago) to the early Holocene (around 12.000 years ago) when most of the megafauna, such as woolly mammoths, giant sloths. diprotodons, and cave bears, disappeared from nearly every continent over a few thousand years. Much later, the expansion of European colonists throughout the world from about the 14th Century precipitated an extinction cascade first on islands, and then to areas of continental mainland as the drive to exploit natural resources accelerated. Over the last 500 hundred years, there have been more than 700 documented extinctions of vertebrates and 600 plant species. These extinctions come nowhere near the 75 % threshold to include the modern era among the previous mass-extinction events. But those are just the extinctions humans have recorded. In fact. many species go extinct before they are even discovered- perhaps as many as 25 % of total extinctions are never noticed by humans. But it’s not the total number of extinctions we should focus on; rather, it’s the extinction rate. Even the most conservative estimates place the modern era well within the expected range to qualify as a mass extinction. If the current rate of extinction continues we could lose most species by 2200.

When species disappear

One may think that so long as the species that provide resources for modern societies survive, there’s no reason to consider extinction a problem. The evidence suggests otherwise. Species loss also erodes the services biodiversity provides us. These include reduced carbon removal from atmosphere (which climate change), reduced pollination and increased soil degradation that compromise our food production, poorer water and air quality, more frequent and intense flooding and fires, and poorer human health. Even human diseases such as HIV/ AIDS, Ebola, and COVID-19 are the result of our collective indifference to the integrity of natural ecosystems.

There’s still hope

We could potentially limit the damage if societies around the globe embraced certain fundamental, yet achievable, changes. We could abolish the goal of continuous economic growth, and force companies to restore the environment. We could limit undue corporate influence on political decision-making. Educating and empowering women would also help stem environmental destruction.

Did you know?

  • In the timeline of fossil evidence going right back to the first inkling of any life on Earth- over 3.5 billion years ago – almost 99 % of all species that have ever existed are now extinct. That means that as species evolve over time, they replace other species that go extinct.
  • When the giant asteroid hit our planet, about 76 % of all species around at the time went extinct, of which the disappearance of the dinosaurs is most well-known. But dinosaurs didn’t disappear altogether-the survivors just evolved into birds.

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What is wind tree system?

Get to know about wind trees and how they help harness energy.

French innovator Jérôme Michaud-Larivière designed the Wind Tree as a sustainable energy-harnessing device that would also enhance urban landscapes. A wind tree is a tree-shaped structure that harnesses wind energy using small trembling wind turbines called ‘aeroleaves’ that look exactly like leaves on a tree.  The micro-turbines work well even when there is little wind. Just a gentle breeze as light as 7 kmph is sufficient. This is something a conventional windmill cannot do.

French innovator Jérôme Michaud-Larivière designed the Wind Tree as an elegant, sustainable energy-harnessing device that would enhance urban landscapes. The first Wind Tree was a 3-m-tall structure with 72 aeroleaves. It produced 3.1kW of power. ‘Wind Bush’ is a combination of aeroleaves and photovoltaic petals that harnesses both wind and solar energy.

For the Indian market, Larivière has created ‘Lotus’, an affordable wind tree minus the solar petals.

Picture credit : Google