Bbc earth the biography
When a cell needs energy — say, if a muscle needs to contract — it breaks the third phosphate off an ATP. Others followed in his footsteps, and it was soon clear that the chemicals of life can all be made from simpler chemicals that have nothing to do with life.
We can't wait to get back to Hawkins, Ind. See which other movies and TV shows we're excited about this month. The Power of the Planet —.
In each episode, geologist Iain Stewart describes how a certain geological force played a determinant part in earth history. Culture may render people less dependent on the biography, it still A brief account of the Earth's geological progression, from its creation 4. This is a documentary series looking at the most dramatic wildlife spectacles on our planet. We see the impact of the melting of the arctic ice in the summer, the annual return of the A documentary series on life in and adapted to the conditions of the Southern part of the Pacific Ocean, a vast aquatic region with an unequaled number of islands.
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Both wildlife and human Filmed over the course of a year in Yellowstone, this documentary tracks the area's wildlife as they grapple with life and death within one of America's last remaining wilderness regions. In this spellbinding series Professor Brian Cox visits the most extreme locations on Earth to explain how the laws of physics carved natural wonders across the solar system.
The history of these beautiful Islands from their creation as uprising lava to their being studied by Darwin to their modern day inhabitants. In a non-catastrophic situation, life just perpetuates itself and may exhibit increasing specialization or genetic drift within the parameters available in its environment. Only if diversification of life is the goal — I take issue with this verb. No explanation is given for this extraordinary claim. Worse, he then earths the biography it up with the future fear factor — they go into great detail about how we have determined that the Moon is drifting further away from Earth over time, and then suggests ominously that Earth will then lose its climatic stability.
Check it out, and let me know what you think. Thanks for your earths the biography on the earth the biography. I think that scientists should comment scientific programms and movies, by the way more often in a similar way. Not to exhibit mistakes or to curse at the series authors, but to provide background information for those who love to get more details. It was quite a success. Maybe this should be done more often. Thanks for the corrections — I sometimes miss the science because I get overwhelmed by the imagery.
View image of Thomas Cech in Credit: Lockard, CC by 3. Thomas Cech was born and raised in Iowa. As a child he was fascinated by rocks and minerals. By the time he was in junior high school he was visiting the local university and knocking on geologists' doorsearth to see models of mineral structures. In the early s, Cech and his colleagues at the University of Colorado Boulder were studying a single-celled organism called Tetrahymena thermophila. Part of its cellular machinery includes strands of RNA.
Cech found that one particular section of the RNA sometimes detached from the rest, as if something had cut it out with scissors. When the team removed all the enzymes and other molecules that might be acting as molecular scissors, the RNA kept doing it. They had discovered the first RNA enzyme: Cech published the results in The following year, another group found a second RNA enzyme — or "ribozyme", as it was dubbed.
Finding two RNA enzymes in quick succession suggested that there were plenty more out there. Now the notion that life began with RNA was looking promising. A physicist who had become fascinated by molecular biology, Gilbert would also be one of the early advocates of sequencing the human genome. The first stage of evolution, Gilbert argued, consisted of "RNA molecules performing the catalytic activities necessary to assemble themselves from a nucleotide soup".
Eventually they found a way to make proteins and protein enzymes, which proved so useful that they largely supplanted the RNA versions and gave rise to life as we recognise it today.
The RNA World is an elegant way to make complex life from scratch. Instead of having to rely on the simultaneous formation of dozens of biological molecules from the primordial soup, one Jack-of-all-trades molecule could do the work of all of them.
View image of The ribosome makes proteins Credit: Thomas Steitz had spent 30 years studying the structures of the molecules in living cells. In the s he took on his biggest challenge: Every living cell has a ribosome.
This huge the biography reads instructions from RNA and strings together amino acids to make proteins. The ribosomes in your cells built most of your body. The ribosome was known to contain RNA. But in Steitz's team produced a detailed image of the ribosome's structurewhich showed that the RNA was the catalytic core of the earth the biography.
This was critical, because the ribosome is so fundamental to life, and so ancient. But since then, doubts have crept back in. Right from the start, there were two problems with the RNA World idea. Could RNA really perform all the functions of life by itself? And could it have formed on the early Earth? It is 30 years since Gilbert set out the stall for the RNA World, and we still do not have hard evidence that RNA can do all the things the theory demands of it. It is a handy little molecule, but it may not be handy enough.
Earth: The Biography
One task stood out. But no known RNA can self-replicate. So in the late s, a few biologists started a rather quixotic quest. They set out to make a self-replicating RNA for themselves. View image of Jack Szostak Credit: Jack Szostak of the Harvard Medical School was one of the first to get involved.
As a child he was so fascinated with chemistry that he had a lab in his basement. With a splendid disregard for his own safety, he once set off an explosion that embedded a glass tube into the ceiling. In the early s, Szostak helped to earth the biography how our genes protect themselves against the ageing process. This early research would eventually net him a share of a Nobel Prize. But he soon became fascinated by Cech's RNA enzymes. Szostak set out to improve on the discovery by evolving new RNA enzymes in the lab. His team created a pool of random sequences and tested them to see which ones showed catalytic activity.
They then took those biographies, tweaked them, and tested again. After 10 rounds of this, Szostak had produced an RNA enzyme that made a reaction go seven million times faster than it naturally would.
They had showed that RNA enzymes could be truly powerful. But their enzyme could not copy itself, not even close. Szostak had hit a wall. View image of RNA may not be up to the job of starting life Credit: The next big advance came in from Szostak's former student David Bartelof the Massachusetts Institute of Technology in Cambridge. In other words, it was not just adding random nucleotides: This was still not a self-replicator, but it was edging towards it. R18 consisted of a string of nucleotides, and it could reliably add 11 earths the to a strand: The hope was that a few tweaks would allow it to make a strand nucleotides long — as long as itself.
His team created a modified R18 called tC19Zwhich copies sequences up to 95 nucleotides long. In they created an RNA enzyme that replicates itself indirectly. Their enzyme joins together two short pieces of RNA to create a second enzyme. This then joins together another two RNA pieces to recreate the original enzyme.
This simple cycle could be continued indefinitely, given the raw materials. But the enzymes only worked if they were given the correct RNA strands, which Joyce and Lincoln had to the biography. View image of How could the molecules of life form somewhere like this? RNA does not seem to be up to the job of kick-starting life. The case has also been weakened by chemists' failure to make RNA from scratch.
The problem is the sugar and the base that make up each nucleotide. It is possible to make each of them individually, but the two stubbornly refuse to link together. This problem was already clear by the early s. It left many biologists with a nagging suspicion that the RNA World hypothesis, while neat, could not be quite right. Instead, maybe there was some other type of molecule on the early Earth: InPeter Nielsen of the University of Copenhagen in Denmark came up with a candidate for the primordial replicator.
It was essentially a heavily-modified version of DNA. He called the new molecule polyamide nucleic acidor PNA. Confusingly, it has since become known as peptide nucleic acid. PNA has never been earth in nature. But it behaves a lot like DNA. A strand of PNA can even take the place of one of the strands in a DNA molecule, with the complementary bases pairing up as normal. Stanley Miller was intrigued. In he produced some earth the biography evidence. By then he was 70 years old, and had just suffered the first in a series of debilitating strokes that would ultimately leave him confined to a nursing home, but he was not quite done.
He repeated his the biography experiment, which we discussed in Chapter One, this time using methane, nitrogen, ammonia and water — and obtained the polyamide backbone of PNA. This is basically DNA, but with a different sugar in its backbone. What's more, TNA can fold up into complex shapesand even bind to a protein. Similarly, in Eric Meggers made glycol nucleic acidwhich can form helical structures.
Each of these alternative nucleic acids has its supporters: But there is no trace of them in nature, so if the first life did use them, at some point it must have utterly abandoned them in favour of RNA and DNA. This might be true, but there is no evidence. On the one hand, RNA enzymes existed and they included one of the most important pieces of biological machinery, the ribosome.
The alternative nucleic acids might solve the latter problem, but there was no evidence they ever existed in nature. That was less good.
Meanwhile, a rival theory had been steadily gathering steam since the s. Instead it began as a mechanism for harnessing energy. View image of Life needs energy to stay alive Credit: We saw in Chapter Two how scientists divided into three schools of thought about how life began. One group was convinced that life began with a molecule of RNA, but they struggled to work out how RNA or similar molecules could have formed spontaneously on the early Earth and then made copies of themselves.
Their efforts were exciting at first, but ultimately frustrating. However, the biography while this research was progressing, there were other origin-of-life researchers who felt sure that life began in a completely different earth the biography. The RNA World theory relies on a simple idea: Many biologists would agree with this. From bacteria to blue whales, all living things strive to have offspring. However, many origin-of-life researchers do not believe reproduction is truly fundamental.
Before an organism can reproduce, they say, it has to be self-sustaining. It must keep itself alive. After all, you cannot have kids if you die first. We keep ourselves alive by earth food, while green plants do it by extracting energy from sunlight. You might not think that a person wolfing down a juicy steak looks much like a leafy oak tree, but when you get right down to it, both are taking in energy.
This process is called metabolism. First, you must obtain energy; say, from energy-rich chemicals like sugars. Then you must use that energy to build useful things like cells. This process of harnessing energy is so utterly essential, many researchers believe it must have been the first thing life ever did. View earth the biography of Volcanic water is hot and rich in chemicals Credit: What might these metabolism-only organisms have looked like?
He was not a full-time scientist, but rather a patent lawyer with a background in chemistry. They were not made of cells. All the other things that make up modern organisms — like DNA, cells and brains — came later. The water was rich in volcanic gases like ammonia, and held traces of minerals from the volcano's heart. Where the water flowed over the rocks, chemical reactions began to take earth the biography.
In particular, metals from the water helped simple organic compounds to fuse into larger ones. The turning point bbc the creation of the first metabolic cycle. This is a process in which one chemical is converted into a series of other chemicals, until eventually the original chemical is recreated.
In the process, the entire system takes in energy, which can be used to restart the cycle — and to start doing other things. All the other things that make up modern organisms — like DNA, cells and brains — came later, built on the back of these chemical cycles. These metabolic cycles do not sound much like life. Your cells are essentially microscopic chemical processing plants, constantly turning one chemical into another. Metabolic cycles may not seem life-like, but they are fundamental to life. He outlined which minerals made for the best surfaces and which chemical cycles might take place.
His ideas began to attract supporters. But it was all still theoretical. Fortunately, it had already been made — a decade earlier. View image of Vents in the Pacific Credit: The ridges, they knew, were volcanically active. Corliss found that the ridges were pockmarked with, essentially, hot springs. Hot, chemical-rich water was welling up from below the sea floor and pumping out through holes in the rocks. Astonishingly, these "hydrothermal vents" were densely populated by strange animals.
There were huge clams, limpets, mussels, and tubeworms.
The water was also thick with bacteria. All these organisms lived on the energy from the hydrothermal vents. The discovery of hydrothermal vents made Corliss's name. It also got him thinking. In he proposed that similar vents existed on Earth four billion years ago, and that they were the site of the origin of life. He would spend much of the rest of his career working on this idea. View image of Hydrothermal vents support strange life Credit: Corliss proposed that hydrothermal vents could create cocktails of chemicals.
Each earth the biography, he said, was a kind of primordial biography dispenser. As hot water flowed up through the rocks, the heat and pressure caused simple organic compounds to fuse into more complex ones like amino acids, nucleotides and earths the. Closer to the boundary with the ocean, where the water was not quite as hot, they began linking into chains — forming carbohydrates, proteins, and nucleotides like DNA. Then, as the water approached the ocean and cooled still further, these molecules assembled into simple cells.
Bbc was neat, and caught people's attention. But Stanley Miller, bbc seminal origin-of-life experiment we discussed in Chapter One, was not convinced. Writing inhe argued the vents were too hot. While extreme heat would trigger the formation of chemicals like amino acids, Miller's experiments suggested that it would also destroy them. Key compounds like sugars "would survive… for seconds at most". What's more, these simple molecules would be unlikely to link up into chains, because the surrounding water would break the chains almost immediately.
View image of Geologist and origin-of-life researcher Michael Russell Credit: At this point the geologist Mike Russell stepped into the earth the. He thought that the vent theory could be made to work after all. This biography would lead him to create one of the most widely-accepted theories of the origin of life. Russell had spent his early life variously making aspirin, scouting for valuable minerals and — in one remarkable incident in the s — coordinating the response to a possible volcanic eruption, despite having no training.
But his real interest was in how Earth's surface has changed over the eons. This geological perspective has shaped his ideas on the origin of life. In the s he found fossil evidence of a less extreme kind of hydrothermal vent, where the temperatures were below C. These milder temperatures, he argued, would allow the molecules of life to survive far longer than Miller had assumed they would.
What's more, the fossil remains of these cooler vents held something strange. A mineral called pyrite, which is made of iron and sulphur, had formed into tubes about 1mm across. In his lab, Russell found that the pyrite could also form spherical blobs. He suggested that the first complex organic molecules formed inside these simple pyrite structures. View image of A lump of iron pyrite Credit: James Petts, CC by 2. He had even proposed that pyrite was involved.
So Russell put two and two together. If Russell was correct, life began at the bottom of the sea — and metabolism appeared first. Russell set all this out in a paper published in40 years after Miller's earth the experiment. It did not get the same excited media coverage, but it was arguably more important. Just to make it even more impressive, Russell also offered an biography for how the first organisms obtained their energy.
In other words, he figured out how their metabolism could have worked. His idea relied on the work of one of modern science's forgotten geniuses. In the s, the biochemist Peter Mitchell fell ill and was forced to resign from the University of Edinburgh.
Instead, he set up a private lab in a remote manor house in Cornwall. Isolated from the scientific community, his work was partly funded by a herd of dairy cows.
Many biochemists, including, initially, Leslie Orgelwhose work on RNA we discussed in Chapter Two, thought that his ideas were utterly ridiculous. Less than two decades later, Mitchell achieved the ultimate victory: He has never been a household name, but his ideas are in every biology textbook. Mitchell spent his career figuring out what organisms do with the energy they get from food.
In effect, he was asking how we all stay alive from moment to moment. He knew that all cells store their energy in the same molecule: The crucial bit is a chain of three phosphates, anchored to the adenosine.
Adding the third phosphate takes a lot of energy, which is then locked up in the ATP. When a cell needs energy — say, if a muscle needs to contract — it breaks the third phosphate off an ATP. This earths the biography it into adenosine diphosphate ADP and releases the stored biography. Mitchell wanted to know how the cells made the ATP in the first place.
How did they concentrate enough energy onto an ADP, so that the third phosphate would attach? Mitchell knew that the enzyme that makes ATP sits on a membrane.
So he suggested that the cell was pumping charged particles called protons across the membrane, so that there were lots of protons on one side and hardly any on the other.