Category: Evolution

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Animals Evolution Life on Earth Oceans

Blue whale facts: How big is the blue whale?

Blue whale and diver
Blue whale size compared to an average human. The blue whale (Balaenoptera musculus) is a marine mammal belonging to the baleen whales (Mysticeti). At 30 metres (98 ft) in length and up to 173 tonnes (191 short tons) in weight, it is the largest extant animal and is the heaviest known to have existed. Photo: dkfindout.com

The blue whale (scientific name: Balaenoptera musculus) is a marine mammal belonging to the baleen whales (Mysticeti). Up to 31 meters (102 feet) in length and 190 tonnes (210 short tons) in weight, it is the largest extant animal and also is the heaviest known to have existed. But it’s hard to conceptualize how big these wonderful animals really are. To put things into perspective, the Facts in Motion channel prepared a video titled “Blue Whales Are Way Bigger Than You Think”. The video also explains the evolutionary reasons behind how and why blue whales get that large.

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Evolution Life on Earth Physics

Is Evolution “just a theory”?

Timeline evolution of life (cropped)
Yes, the Theory of Evolution is a theory, but guess what? When scientists use the word theory, it has a different meaning to normal everyday use. A scientific theory is an explanation of some aspect of the natural world that has been substantiated through repeated experiments or testing. In science, a theory is not a guess, not a hunch. It’s a well-substantiated, well-supported, well-documented explanation for our observations. It ties together all the facts about something, providing an explanation that fits all the observations and can be used to make predictions. In science, the theory is the ultimate goal, the explanation. It’s as close to proven as anything in science can be. Image: Timeline evolution of life on Wikimedia

I recently saw a question on Quora and it was like that: “Why is it called the ‘theory of evolution’ but the ‘law of gravity’?” This question is strongly related to a common misconception about evolution: “It is just a theory” – creationists always say “Evolution is just a theory”.

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Solar System Animals Astronomy Evolution Life on Earth Planet Earth Plants

Earth without Moon: what would it be like?

Supermoon
The supermoon over the Dutch Caribbean, 50 miles north of Venezuela, November 15, 2016. Image: Betty Wills The Moon follows an elliptic orbit around Earth. Naturally, sometimes it gets closer to the Earth than the other times. When it's also full moon at its closest point to the Earth, it's called Supermoon. As a result, the moon appears larger and brighter than usual in the sky.

The Moon is the Earth’s only natural satellite. It is also the fifth-largest natural satellite in the Solar System and the largest among planetary satellites relative to the size of the planet that it orbits. It formed about 4.51 billion years ago from the debris left over after a giant impact between Earth and a Mars-sized body called Theia (this is known as the Giant Impact Hypothesis and is the most widely accepted explanation of the formation of the Moon). This impact happened not long after the Earth has been formed. But, what if that giant impact never happened? What would the Earth without Moon be like?

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Prehistoric Evolution Life on Earth Planet Earth

Dinosaurs were already doomed as the frequency of Asteroid Impacts increased 290 million years ago

Chicxulub impact
The Chicxulub impactor was an asteroid or comet at least 10 kilometers (6 miles) in diameter. Around 66 million years ago, it impacted a few miles from the present-day town of Chicxulub in Mexico, at around 64,000 kilometers per hour (40,000 mph). The impact has created a crater (Chicxulub crater) more than 180 km (110 miles) in diameter, making it the third largest known impact crater on Earth. Image credit: Joe Tucciarone/Science Photo Library

By studying lunar craters, scientists have discovered that asteroid impacts became more frequent about 290 million years ago. So was just a matter of time for dinosaurs to become extinct.

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Planet Earth Evolution Life on Earth Solar System

What if the Earth was tidally locked to the Sun?

Sunrise from space (NASA)
Image: NASA - ISS013-E-78960 (9 Sept. 2006) - A rising sun and Earth's horizon are featured in this image photographed by an Expedition 13 crew member on the International Space Station.

We only see one side of the moon, because it is tidally locked to the planet Earth (tidal locking the situation when an object’s orbital period matches its rotational period). What if the Earth was tidally locked to the Sun?

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Life on Earth Animals Evolution Planet Earth Plants Prehistoric

What If Earth’s History Compressed Into One Year

Earth from the Geostationary Orbit
Earth image taken by Japanese weather satellite Himawari 8, which takes a photo of Earth every 10 minutes. Himawari 8 is the 8th of the Himawari geostationary weather satellites operated by the Japan Meteorological Agency. Himawari 8 entered operational service on 7 July 2015 and is the successor to MTSAT-2 (Himawari 7) which was launched in 2006.

What if the Earth’s history (our planet’s age is approximately 4.54 billion years), compressed into just one year? @YearOnEarth just did that. At midnight on the 31st of December, Chris Jennings started a little project for the incoming year: tweeting the entirety of the geological history of the Earth, compressed into one year.

The result is an amazing timeline of the Earth’s history.

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Astrobiology Evolution

Proof of life: how would we recognize an alien if we saw one?

An octomite
An 'octomite', or a speculative alien produced by natural selection. Courtesy Helen Cooper/Cambridge University The researchers imagine a complex alien called the ‘Octomite’ which is comprised of a hierarchy of entities, where each lower level collection of entities has aligned evolutionary interests such that conflict is effectively eliminated. These entities engage in division of labour, with various parts specialising on various tasks, such that the parts are mutually dependent.

What would convince you that aliens existed? The question came up recently at a conference on astrobiology, held at Stanford University in California. Several ideas were tossed around – unusual gases in a planet’s atmosphere, strange heat gradients on its surface. But none felt persuasive. Finally, one scientist offered the solution: a photograph. There was some laughter and a murmur of approval from the audience of researchers: yes, a photo of an alien would be convincing evidence, the holy grail of proof that we’re not alone.

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Life on Earth Animals Evolution

8 major extinctions due to human interference

Landscape with Birds by Roelant Savery, 1628
Landscape with Birds, (showing a dodo in the lower right corner) by Roelant Savery, 1628. Image Courtesy Wikimedia Roelant Savery (or Roeland(t) Maertensz Saverij, or de Savery, or many variants) (1576 - buried 25 February 1639), was a Flanders-born Dutch Golden Age painter. He primarily painted landscapes, often embellished with many meticulously painted animals and plants, regularly with a mythological or biblical theme as background. Among his best-known works are several depictions of the now-extinct dodo painted between 1611 and 1628.

If you are one among the many who have watched the movie Rio and have fallen in love with the adorable lead named Blu, then I have some terrible news for you! As of this date, the Spix’s Macaw has been declared “extinct as in wild”.

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Life on Earth Evolution

There are more microbial species on Earth than stars in the galaxy

Dwindling Diatoms
Earth's oceans teem with microscopic plants called phytoplankton. But according to a new NASA study, populations of diatoms, the largest type of phytoplankton algae, have declined more than 1 percent per year from 1998 to 2012. Phytoplankton are an essential base of the marine food web and absorb carbon dioxide dissolved in the ocean that originally came from the atmosphere. The tiny organisms occupy the uppermost layer of ocean water, called the mixed layer, where waves and currents continually churn, drawing up nutrients from a deeper layer of water below. Scientists say the phytoplankton declines observed over the 15-year study period are due to the mixed layer becoming shallower, which results in fewer nutrients reaching the diatoms. The reduction in population may reduce the amount of carbon dioxide drawn out of the atmosphere and transferred to the deep ocean for long-term storage. Image and text: NASA

For centuries, humans have endeavoured to discover and describe the sum of Earth’s biological diversity. Scientists and naturalists have catalogued species from all continents and oceans, from the depths of Earth’s crust to the highest mountains, and from the most remote jungles to our most populated cities. This grand effort sheds light on the forms and behaviours that evolution has made possible, while serving as the foundation for understanding the common descent of life. Until recently, our planet was thought to be inhabited by nearly 10 million species (107). Though no small number, this estimate is based almost solely on species that can be seen with the naked eye.

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Prehistoric Animals Evolution Geography Geology Insects Life on Earth Planet Earth Plants

Here’s What did Ancient Earth Look Like

Ancient Earth (280 million years ago)
Ancient Earth (280 million years ago). Permian period. The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the Russian city of Perm. The Permian witnessed the diversification of the early amniotes into the ancestral groups of the mammals, turtles, lepidosaurs, and archosaurs. The world at the time was dominated by two continents known as Pangaea and Siberia, surrounded by a global ocean called Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, who could better cope with these drier conditions, rose to dominance in place of their amphibian ancestors. Extreme conditions such as polar ice caps and deserts limited the extent of plant life, but amphibious tetrapods and reptiles diversified where plants grew. Oceans teemed with fish and invertebrate life.

I stumbled upon an amazing web page showing what did ancient Earth look like. On the “Dinosaur Pictures and Facts” web page (dinosaurpictures.org), there’s also an interactive animation. On this page, you can either select the years (i.e. 600 million years ago) or jump to a particular event (i.e. first multicellular life) and see how ancient Earth did look like then. You can also remove the clouds and stop the Earth’s rotation if you want to.

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