Tag Archives: organisms

It Is Possible Jupiter Could Support Life, Scientists Say

Jupiter and its shrunken Great Red Spot. Credit: Wikimedia Commons.

Jupiter and its shrunken Great Red Spot. Credit: Wikimedia Commons.

A new factor has been added to the debate on whether or not living organisms could exist on Jupiter. You probably know Jupiter is a Jovian planet, a giant formed primarily out of gases. So how could alien life be able to exist in an environment where most of the phases of matter are absent? The answer is simply found in the element of water.

Within the rotating, turbulent Great Red Spot, perhaps Jupiter’s most distinguishable characteristic, are water clouds. Many of the other clouds in this enormous perpetual storm are comprised of ammonia and/or sulfur. Life theoretically cannot be sustained in water vapor alone; it thrives in liquid water. But according to some researchers, the fact alone that water exists in any form on the planet is a good first step.

The Great Red Spot is still a planetary feature which stumps much of the scientific community today. As it has been observed for the past century and a half, the Great Red Spot has been noticeably shrinking. The discovery of water clouds may lead to a deeper understanding of the planet’s past, including whether or not it might have sustained life, as well as weather-related information.

Some scientists have pondered the possibility that, due to the hydrogen and helium content in its atmosphere, Jupiter could be a diamond-producing “factory.” They have further speculated that these diamonds could enter into a liquid state and a rainfall of liquid diamonds would be in the Jovian’s weather forecast.

Likewise, the presence of water clouds means that water rain (a liquid) is not entirely impossible. Máté Ádámkovics, an astrophysicist at Clemson University in South Carolina, had this to say on the matter:

“…where there’s the potential for liquid water, the possibility of life cannot be completely ruled out. So, though it appears very unlikely, life on Jupiter is not beyond the range of our imaginations.”

Scientists are acting accordingly, researching the part which water plays in the atmosphere and other natural systems on Jupiter. They remain skeptical but eager to follow up on the new discovery. They shall also strive to find out just how much water the planet really holds.

Mistaken Point

Life went multi-cellular to spread kids around more easily, new research suggests

Life on Earth may have first grown to macroscopic sizes not to compete for food, but to spread their genes far and wide.

Mistaken Point

Ediacaran fossils at Mistaken Point, Newfoundland.
Image credits Emily Mitchell.

Complex life is all about making babies — and spreading them far, according to new research led by the University of Cambridge. In a newly-published paper, they report that the most successful complex species living in the ocean over half a billion years ago were the ones who could spread their offspring the farthest, thus colonizing more land.

Wildest oats

Prior to what geologists refer to as the Ediacaran period (between 635 and 541 million years ago), life on Earth was content to stay microscopic. During the Ediacaran, however, we see the first complex (multicellular) organisms. Some of them, such as the rangeomorphs, could grow up to two meters tall.

We don’t know a whole lot about rangeomorphs. We don’t really know if they were plants or animals, for that matter. What we do know is that they look a lot like ferns and that they’re among the first complex life forms to evolve on the planet — although that’s hard to confirm. Like all other organisms hailing from the Ediacaran, they had no mouths, don’t seem to have had any organs, and lack any obvious means of locomotion — so they were likely filter-feeders, like modern-day clams for example.

One interesting pattern that emerges from the fossil record is that these Ediacaran organisms tended to become more diverse over time — and eventually developed stem-like structures to keep them upright. It was these stems that prompted the research. Plants today also sport stems, and most use height to outcompete their neighbors for resources such as light. But we don’t know if rangeomorph stems served as a means to one-up competitors — although previous research has suggested that their increase in size was driven by competition for nutrients at different water depths.

Ediacaran life.

Artist’s reconstruction of Ediacaran life.
Image credits Ryan Somma / Flikr.

“We wanted to know whether there were similar drivers for organisms during the Ediacaran period,” said Dr Emily Mitchell of Cambridge’s Department of Earth Sciences, the paper’s lead author. “Did life on Earth get big as a result of competition?”

“The oceans at the time were very rich in nutrients, so there wasn’t much competition for resources, and predators did not yet exist. So there must have been another reason why life forms got so big during this period.”

Mitchell and co-author Dr. Charlotte Kenchington, from Memorial University of Newfoundland in Canada, worked with fossils retrieved from Mistaken Point, in south-eastern Newfoundland. This area is one of the richest sites of Ediacaran fossils in the world.

Since Ediacaran organisms were immobile, they were preserved where they lived. As such, the team could analyze entire populations from the fossils. Using spatial analysis techniques, the duo found that there was no correlation between individual size and competition for food. In other words, the rangeomorphs did not tier — they didn’t occupy different parts of the water column to avoid competing for food with their peers.

“If they were competing for food, then we would expect to find that the organisms with stems were highly tiered,” said Kenchington. “But we found the opposite: the organisms without stems were actually more tiered than those with stems, so the stems probably served another function.”

The team believes that the stems were used to enable a greater dispersion of offspring — which rangeomorphs produced by expelling ‘propagules‘. The tallest organisms were surrounded by the largest clusters of offspring, the team found, suggesting that height helped individuals colonize a greater area with their offspring.

Still, about 540 million years ago, rangeomorphs and other Ediacaran organisms disappeared from the fossil record. It’s the Cambrian period now, and evolution is having a blast designing new and surreal creatures — including predators. Rangeomorphs, without the ability to move around, couldn’t do much to protect themselves against these predators.

The paper “The utility of height for the Ediacaran organisms of Mistaken Point” has been published in the journal Nature Ecology & Evolution.

Why Stephen Hawking Was Afraid of Aliens

Young Stephen Hawking.

Professor Stephen Hawking, the theoretical physicist hailed as one of the most brilliant scientists of the modern age, had genuine anxieties. Thus, intelligence does not necessarily reject fear. Hawking had one fear in particular which deserves noting, namely humanity’s encounter with advanced alien life.

Several of the late physicist’s theories have been shown to be quite accurate and are widely accepted in the scientific community. When he spoke (through his speech synthesizer) people gave ear and were attentive. Like any man, he too had his faults both public and personal. But simply because the man has passed away, does not mean we should disregard what he did and said during his time on Earth.

He made numerous predictions about the present and future problems that the human race faces, involving issues such as overpopulation and artificial intelligence. Perhaps one of his most intriguing and logically-stated beliefs was a concern for detrimental interaction between human beings and extraterrestrial beings.

Unlike astrophysicist Carl Sagan, who was rather optimistic about extraterrestrial contact, Hawking worried about the effects such contact might have on our race, even though the Professor assisted in founding projects to seek intelligent alien organisms. Some may fear aliens as they are depicted in sci-fi and horror stories: ugly creatures capable of taking over human beings and using them as their hosts.

The physical appearance of hypothetical aliens is not what alarmed Stephen Hawking. It was something a bit more sinister. In short, he apparently was cautious of entertaining alien contact because of the possibility that intelligent alien civilizations may want to dominate our race. They might do this either by enslaving people or slaughtering them, or both.

He has related these concerns publicly as early as 2010. In 2016, he speculated that if Earth received a signal of alien origins “we should be wary of answering back.” He further argued this point by employing historical references. “Meeting an advanced civilization could be like Native Americans encountering Columbus,” he said. “That didn’t turn out so well.” Sometime in the future, if we’re not cautious in the search for alien life, humans might rue ignoring Stephen Hawking’s worries about extraterrestrials.

Rangeomorphs.

The earliest large organisms on Earth were shapeshifters

A new paper published by researchers from the University of Cambridge and the Tokyo Institute of Technology could answer why life made the transition from the first really small things to the really large organisms we see today.

Rangeomorphs.

An artist’s impression of rangeomorphs.

Life started out with the tiny bits: proteins, viruses, bacteria, algae. Somewhere along the way, however, it also made the transition towards larger organisms — which is how us, dogs, whales, and so on, got to be here today. But why and when did life perform this transition?

A new study determined that one of the first large organisms we know of, rangeomorphs, were able to grow up to two meters in height at a time when most organisms were still going about on the cellular level. Even more impressively, they were able to change their body’s size and shape as they adapted to environmental conditions. The team’s results could help explain how life as we know it today, and how the giants of the past, could evolve from microscopic organisms.

One size fits all

Rangeomorphs were ocean-dwelling organisms that lived between 635 and 541 million years ago in a period known as the Ediacaran period. Their bodies consisted of branches, each with many smaller side branches, that similarly harbored many tiny branches, forming a fractal. It’s a bit like the shape a snowflake has under a microscope, but with many more sets of branching arms.

Rangeomorphs represent some of the earliest large organisms to evolve on Earth, and could grow from a few centimeters up to two meters in height. But they’re also very strange, as far as life goes. In fact, they’re so strange that there isn’t anything living today that resembles them — so we don’t really know how they fed or grew or made more of themselves, or how they fit into the tree of life. And although they look suspiciously plant-like, researchers believe that rangeomorphs were actually animals.

“What we wanted to know is why these large organisms appeared at this particular point in Earth’s history,” said Dr Jennifer Hoyal Cuthill of Cambridge’s Department of Earth Sciences and Tokyo Tech’s Earth-Life Science Institute, the paper’s first author.

“They show up in the fossil record with a bang, at very large size. We wondered, was this simply a coincidence or a direct result of changes in ocean chemistry?”

To find out, the team used micro-CT imaging and took photographic measurements of rangeomorph fossils uncovered in south-eastern Newfoundland, Canada, the UK, and Australia. They then fed this data into computer models to help them better understand the animals’ physiology.

They report that rangeomorphs show the earliest known evidence of nutrient-dependent growth in the fossil record. Obviously, all organisms depend on nutrients to survive and grow but certain species can actually change body size and shape depending on nutrient availability (ecophenotypic plasticity).

Ediacaran sea life.

Reproduction of what an Ediacaran sea looked like.
Image credits Ryan Somma / Flickr.

Rangeomorphs show a very strong degree of ecophenotypic plasticity, which the team believes gave them a very powerful adaptive advantage. The Earth was going through very dramatic changes in the Ediacaran, and rangeomorphs could rapidly “shape-shift” to adapt to environmental pressures — for example, they could grow to a tall, tapered edge if the seawater above had higher levels of oxygen.

“During the Ediacaran, there seem to have been major changes in the Earth’s oceans, which may have triggered growth, so that life on Earth suddenly starts getting much bigger,” Hoyal Cuthill added.

“It’s probably too early to conclude exactly which geochemical changes in the Ediacaran oceans were responsible for the shift to large body sizes, but there are strong contenders, especially increased oxygen, which animals need for respiration.”

This shifting chemical background came in the wake of a large-scale ice age known as the Gaskiers glaciation. The cold climate kept nutrient levels low, which in turn kept mean organism body sizes low. But a sudden (geologically speaking) increase in free oxygen and nutrients during the Ediacaran period, ecosystems could support much larger organisms, meaning large rangeomorphs could have been a direct result of major changes in climate and ocean chemistry.

But environmental changes would eventually spell their undoing, too. While rangeomorphs were very well adapted to their Ediacaran lifestyle, oceanic conditions continued to change, leading to the ‘Cambrian Explosion‘ — an unprecedented evolutionary development, which saw an immense explosion of biodiversity and to which most major animal groups in the fossil record can trace their ancestry. Between shifting environmental conditions and strong competition and predation, rangeomorphs went extinct.

The paper “Nutrient-dependent growth underpinned the Ediacaran transition to large body size” has been published in the journal Nature Ecology and Evolution.

Scientists discover LUCA, common ancestor of all living things

A new study suggests that that the Last Universal Common Ancestor (LUCA) of all living things is a four-billion-year old single-celled organism that lived in extremely hot hydrothermal vents.

A hydrothermal vent in the Northwest Eifuku volcano. Credit: National Oceanic and Atmospheric Administration (NOAA)

A hydrothermal vent in the Northwest Eifuku volcano. Credit: National Oceanic and Atmospheric Administration (NOAA)

All of the living organisms on Earth can be separated into three basic categories: eukaryotes, bacteria, and archaea. While eukaryotes, which encompass all plants and animals, possess a nucleus and membrane-bound organelles, bacteria and archaea do not. Despite these differences, scientists believe that all of these three groups originated from a common ancestor, which the new data suggests is LUCA.

Comparison of protein-coding genes in bacteria and archaea led to the identification of 355 genes that likely originated in LUCA. Further examination revealed a gene that codes for the reverse gyrase enzyme, which is only found in microbes that exists in extreme temperature conditions.

The genetic profile created in the study suggests that LUCA lived in deep-sea vents of extremely hot temperatures where it metabolized hydrogen gas for energy due to the lack of available oxygen. This hydrogen gas was likely created by the geochemical activity in the Earth’s crust.

LUCA’s cellular structures were probably composed of “inert” gases such as carbon dioxide and nitrogen. Enzyme creation likely stemmed from iron due to its free availability, and the lack of oxygen means that it wouldn’t have been turned into insoluble rust.

The results are interesting to say the least, but there is still no way to directly verify them. However, the new information can be used to create experiments that simulate the conditions that LUCA thrived in and attempt to recreate primitive life, although given the extreme conditions of hydrothermal vents, this will be a difficult task.

Journal Reference: The physiology and habitat of the last universal common ancestor. 25 July 2016. 10.1038/nmicrobiol.2016.116