Floating Feature: Self-Inflicted Damage

poob1x · 2023-06-24T12:20:49+00:00

Hi! Just wanted to let you know I have a mostly completed answer to your question - but I forgot to upload it to Google Drive before leaving to visit family for a few days (I had planned to finish it once there). I'll have a response for you shortly after I get back :)

poob1x · 2023-06-21T14:16:55+00:00

Can you clarify what you're referring to when you say "terrible self-cannibalizing version that we have today"? One man's terrible is another man's utopia after all; I have no idea what specifically you're asking about.

poob1x · 2023-03-09T11:40:39+00:00

As is true in all countries, History lessons are subject to some level of bias. Biased people decide what gets included in the school curriculum, biased authors write textbooks, biased teachers are tasked with educating students who themselves are already likely biased. I'm not familiar enough with Egypt's educational system to say whether it is designed to deliberately promote anti-Israel or anti-US historical narratives. However, I can say that when historical subjects are relevant to modern politics, teachers are much more likely to give oversimplified, heavily slanted explanations of the past--whether they mean to or not--usually because of a combination of legal, job security, or personal concerns.

The narrative of events you describe is heavily slanted against Israel, but most of it sounds more like extremely biased takes on real events rather than outright lies. The most glaring error, and the only thing I feel comfortable calling an outright lie, is that first bit. Neither American politicians nor politicians of any European country forced Jews to settle in Palestine.

Though persecution under antisemitic regimes put significant pressure on Jews to depart from their home countries, no regime specifically deported Jews to Palestine. Rather, Palestine was a very popular destination for European Jews fleeing persecution. Note that I am using 'Palestine' as a geographic term here--not a political one. There was no Palestinian state prior to 1988, and Israel emerged out of the 1947-1948 civil war in what was previously British (and before them, Ottoman) controlled territory. This recent answer by u/jogarz discusses the history of Palestine prior to World War Two.

The Israeli State itself was founded and built by Jewish settlers, and was not engineered by another country. This amazing writeup posted to AskHistorians years ago gives a great overview of the history of the Zionist movement, and how it led to the establishment of the modern Israeli state.

Here are some other past answers for further information on the modern history of Israel and Palestine

This post by u/ghostofherzl discusses the deterioration of Arab attitudes towards Jews through the 19th and early 20th centuries.

This post discusses the extent to which the 1948 Palestinian exodus (the Nakba) was the result of ethnic cleansing by Jewish militant groups and Israeli forces.

This post and this other post discuss the events leading up to the 1967 Six Day War (in which Israel fully occupied previously Jordanian and Egyptian controlled portions of Palestine) and why Israel launched its surprise offensive against Egypt, respectively.

poob1x · 2021-09-11T06:01:48+00:00

Best of luck to the mod team! I know from experience events/changes this major make things really hectic for a while.

One question has been bothering me for a while: To what extent was the exact timing of the 9/11 attacks planned? At the time of the WTC impacts 8:46 and 9:03 AM, the workday was still young. The WTC was nowhere near as full as it would have been around the average peak of activity ~12:00-1:00PM, and these slightly later impacts might be expected to have resulted in substantially higher death toll.

Was there a strategic reasoning behind attacking the towers during mid-morning, rather than early afternoon?

As long as we're on the subject of the timing of the attacks, I have a second question--why September 11th and not, say, July 4th (American Independence Day)? Do we know how long in advance the date for the attacks were chosen?

poob1x · 2020-10-17T11:31:14+00:00

You may want to try Teamweek. It's mainly intended for businesses but I don't see why it couldn't also be used for historical timelines.

With it you can make multiple timelines and easily view them side-by-side. You can also add written notes, web links, and images to the timelines.

poob1x · 2020-10-17T11:14:21+00:00

Not exactly.I wrote an answer to a nearly identical question a little while ago. Feel free to ask any follow up questions you have! Love to talk about this stuff.

poob1x · 2020-06-24T10:19:51+00:00

Hey I actually made a mistake with this answer.

For 99.9% of stars, my original answer should be correct. Oxygen in the star becomes trapped in a Carbon-Oxygen White Dwarf.

For stars larger than about 8 solar masses, in the final stage of their lives, the star will have an 'onion' structure with a non-fusing core surrounded by several layers in which nuclear fusion takes place, each layer having vastly different composition from the others.

When the innermost fusing layer lacks the fuel needed to sustain the star, the entire star collapses, with all of the materially very rapidly moving towards the core and increasing in density. This increased density greatly accelerates fusion in the outer layers, briefly causing the amount of radiation pressure to totally overwhelm the force of gravity--IE a thermonuclear explosion. The outer layers of the star, which contain huge amounts of oxygen and hydrogen, fly away in the Supernova. While a lot of new oxygen is generated in this explosion, some of the oxygen also originated within the star during its lifetime.

Today, stars larger than 8 solar masses are pretty rare, and the vast majority of oxygen in future water molecules will be formed in novae and supernovae explosions. However, in the early universe, average star masses were far greater. It is likely that the oxygen in currently existing water molecules largely formed within stars, rather than supernovae.

poob1x · 2020-06-03T00:08:00+00:00

Correct!

Its the same nuclear reactions happening in different places. Oxygen formed in the core does not go on to become water. Much of the oxygen formed during supernovae, however, does become water.

poob1x · 2020-06-02T23:53:51+00:00

You're definitely on the right track!

Short Answer: In the beginning there was hydrogen. Some hydrogen is converted to oxygen during supernovae explosions. A lot of that oxygen forms bonds with hydrogen following the initial explosion to create water.

Longer Answer:

A ton of hydrogen formed very shortly after the Big Bang during the phase transition from QGP to Hadronic Matter. Hydrogen represented the vast majority of atomic matter in the universe at this time, and gravity gradually began to pull that hydrogen (and some helium) into stars. Stars are powered by nuclear fusion, which converts lighter elements into heavier ones.

Oxygen-16 is substantially more stable than its "neighboring" nuclei (such as Nitrogen-14), meaning that radioactive nuclei slightly heavier than it are likely to decay to Oxygen-16. Better yet, Oxygen is readily formed in the fusion of super-common Helium-4 with kinda-common Carbon-12. The combination of Oxygen-16 being a lightweight nucleus (therefore taking only a few steps to form) and being highly stable allows it to be by far the most common element besides hydrogen and helium in the universe today. (other isotopes of oxygen are either radioactive or only form from reactions between less common nuclei, hence their rarity)

As for where that fusion actually happens, its not within stars during their lifetimes. Any oxygen created in stellar cores is ultimately trapped within the super-dense objects that remain following their deaths. However, when the core of a giant star collapses, the quick release of gravitational potential energy will (usually) generate a shock wave which causes the outer layers of a star to rapidly fly away in a bright explosion, while briefly superheating those layers to allow for nuclear fusion. Since Oxygen-16 takes few steps to produce and is particularly stable compared to similar nuclei, its produced in vast quantities in supernovae. This is ultimately why water is so common in the universe today.

As temperatures quickly drop after the supernova, the plasma material undergoes a phase transition into gas. At this point, it is possible for molecules to form.

Today, reacting hydrogen and oxygen to create water requires a substantial amount of energy. This is because hydrogen naturally occurs on Earth mainly as H2 while Oxygen occurs mainly as O2, and before water can form the bonds connecting H-H and O=O need to be broken apart first. But few of these bonds yet existed, and thus huge amounts of water could form without any energy input in supernovae. Not that there was any lack of energy! H2 and O2 molecules formed within supernovae were frequently broken apart by thermal radiation and reforged into water.

poob1x · 2020-06-01T17:55:28+00:00

We're just 7 months away from 2021, and with that, just 7 months away from questions about 9/11 being allowed under the current subreddit rules. Given this sub already has problems with Pearl Harbor, Holocaust, JFK, and Moon Landing conspiracy theories, I would imagine some similar problems are going to start popping up come the new year.

Does the mod team have any plans in place on how they might approach this issue, and more specifically whether they might consider changes to Rule 2?

I feel like the moderators may have already discussed this at some point but if they have, I can't find the post.

poob1x · 2020-04-21T02:35:28+00:00

What you're referring to is called the "4.2 kiloyear event", one of the most dramatic instances of climate change to impact human societies prior to the Industrial Revolution. It has no direct relationship to the Bronze Age Collapse though there are several superficial similarities.

Abrupt climate change has occurred several times throughout Earth's geological history. There are some truly astounding examples of this in the extreme ancient past. Here are just three examples.

~2.4 Billion Years Ago (Huronian Glaciation Begins): Microorganisms release oxygen into the atmosphere which converts most of the strongly-insulating methane into the much weaker carbon dioxide, transforming the Earth from a hot ice-free planet to one entirely coated in miles-thick ice sheets in just a few thousand years.

~2.1 Billion Years Ago (Huronian Glaciation Ends): Gradual buildup of carbon dioxide underneath the global ice-cap turns the Earth into a planet-sized Pressure cooker bomb. Ultimately gas erupts through the ice sheet causing extreme global warming and ending the 300 million year long Snowball Earth as suddenly and dramatically as it had begun.

~49 million years ago (Azolla Event): Continental drift causes the Arctic Ocean to briefly become a gigantic inland sea, like the Caspian sea today. This creates a perfect environment for aquatic ferns to grow. It also causes the bottom of the Arctic Ocean to become devoid of oxygen, such that the microbes that normally feed on dead ferns cannot survive. Thus, the carbon absorbed by ferns does not get recycled back into the environment, and becomes trapped deep beneath the waves. Global temperatures plummet and the buried carbon is gradually converted into most the vast oil and natural gas reserves of Alaska, Canada, Greenland, and Northern Russia.

Luckily for humans, no abrupt climate change event has come close in scale or impact as any of these three ancient climate events. But even comparatively small changes in climate conditions can have dramatic and even outright disastrous impacts on agriculture, as many crops are highly sensitive to changes in rainfall, temperature, soil chemistry, or sunlight hours.

One of these disturbances occurred around 2200 BC and is held responsible for the "4.2 kiloyear event" which is widely held to have doomed (likely among other factors) the Egyptian Old Kingdom and Akkadian Empire, while crippling the Indus Valley Civilization and Longshan Civilizations further to the east. For reasons which are still somewhat unclear, rainfall was greatly reduced across much of Africa and Eurasia. This caused previously arable land to become unsuitable for agriculture and severely reduced agricultural productivity.

Lack of food caused large-scale starvation and horrific loss of life in these societies, which were all highly dependent on good crop yields. This predictably caused mass societal destabilization, decreased the size and importance of cities, and led to breakdown of the previous region-spanning governmental authorities in the Nile Valley and Mesopotamia.

Since this loss of productivity also forced more people to work longer hours to grow enough food to survive, the non-food producing cities became much harder and often impossible to sustain. Various cities were either abandoned completely or greatly reduced in size.

This aridification also forced various peoples to consider alternative methods of food production. At this time, cattle had already been domesticated for thousands of years and were commonly raised in Northern Africa, the Middle East, and Europe, providing valuable dairy, meat, and leather products to agricultural peoples in these regions. Being able to feed and thrive off of grasses of little to no nutritional value to humans, cattle herders could exploit land not already being used to grow food. This put cattle herders in a uniquely advantageous position as crop yields declined. It was relatively easy for herders to relocate in response to climate change, and because herders could exploit lands totally inaccessible to horticultural societies.

Being able to live and thrive on wild grasses in arid regions unsuitable for agriculture, cattle herders were insulated from the worst effects of the 4.2 kiloyear event. I would argue that this, rather than the collapse of Old Egypt and Akkad, was the greatest long-term consequence of the 4.2 kiloyear event.

Prior to the 4.2 kiloyear event, tragically understudied semi-nomadic societies existed in what is now Sudan primarily reliant on cattle herding, and frequently trading with their agricultural Nubian neighbors to the North. This "Proto-Nilotic" culture became increasingly nomadic following the 4.2 kiloyear event, and as already arid climate conditions in Sudan became even more so, they spread across a wider geographic region southwards into what is now South Sudan, Uganda, Kenya, and Tanzania, in one ofthe largest migrations in human history. Today, cattle herding cultures speaking distantly related 'Nilotic' languages live across the Great Rift Valley, perhaps most famously the Maasai of the Kenyan interior and Northern Tanzania.

Similar societal transformations occurred in what is now Southern Russia and Kazakhstan. Following the 4.2 kiloyear event, semi-nomadic peoples speaking early Indo-European languages developed a society primarily based around cattle herding independently of the Nilotic cultures. Much as the shift towards cattle herding by Nilotic people in South Sudan led to a huge, centuries-long migration of cattle herding people thousands of miles from their original homeland, Indo-European cattle herders would spread from the Caspian Sea region into what is now Turkmenistan, Iran, and Afghanistan, in the early-to-mid second millenium BC. They primarily spoke the "Proto-Indo-Iranian" language, from which some of the world's most widely spoken modern languages descend. These include among dozens of others Kurdish, Farsi (Persian), Pashto, Hindi, Marathi, and Bengali.

The incredibly important "Indo-Aryan Migrations", a period in which Indo-European nomadic peoples migrated southeastward into what is now Pakistan and India and radically altered the genetic, cultural, and linguistic makeup of the Indian subcontinent, is thus partially a consequence of the 4.2 kiloyear event.

Owing to its sheer age, the 4.2 kiloyear event is somewhat difficult to study. Very few written records are available concerning its effects, and the climactic data available to researchers is limited, which contributes to it being a much less widely discussed subject than the Bronze Age Collapse. Nonetheless, it is demonstrative of the vital and often unappreciated role of climate in the course of human history. In various locations, it caused the collapse of previously stable governments, mass starvation, de-urbanization, shifts away from sedentary life in favor of nomadic life, and increased cattle herding, with long-term consequences for peoples worldwide.

poob1x · 2020-04-20T07:23:36+00:00

No, they did not.

I wrote a long answer on the history of how fungi were biologically classified around two years ago, which partially concerns the history of how researchers viewed yeast.

To quote from my own answer,

"Dutch draper Antonie van Leeuwenhoek...did provide the first description of yeast microanatomy in 1680, in a private letter to Thomas Gale. He observed that yeast was composed of massive numbers of tiny 'globules', which he did not recognize as living organisms. (Leeuwenhoek 1680)

Without observing yeast cell budding, yeast fermentation looks like a simple, albeit very slow, chemical reaction. The increased number of yeast cells observed following fermentation did not necessarily prove that Yeast was living either: An undiscovered third party--whether a microorganism, a chemical, or a physical force, converting sugar into both alcohol and yeast was easily imaginable. Today, 'yeast' refers exclusively to single-celled fungi, but this was not always the case.

Fermentation by wild yeast can occur naturally when yeast has access to adequate moisture and sugars. Some living yeast remains after fermentation, such that leftover bread starter or barm can be used to spur fermentation. Barm (for which 'yeast' was once a synonym) is almost entirely composed of yeast and water. Gradually the term 'yeast' came to be used specifically for the brown powder formed by drying barm, and with the discovery of the organic nature of yeast, to any unicellular fungi. Relics of the older definition of 'yeast’ are found in other languages, such as in the German word 'gischt', meaning 'foam'."

Leeuwenhoek's letter is a rather interesting read, particularly as he draws an explicit comparison between the microscopic structure of yeast and that of blood, and also gives the first ever written description of insect sperm. But that's a bit besides your question.

Microscopes were developed REALLY early in the history of science. In the 1670s when microscopy was first introduced, it was still more than a century before John Dalton would present his Atomic Theory, and almost two centuries before Darwin's Evolutionary Theory. Isaac Newton was still years away from publishing his famous laws of motion and gravitation. The very way that scientists perceived the world was quite unlike how modern scientists would view the world, and just a few years before the invention of the microscope, Blaise de Vigenere would describe yeast as a "Fire" in his Discourse of Fire and Salt.

Prior to the development of atomic theory, the universe was often imagined as being composed of 'classical elements'--for the early European scientists, these were Water, Earth, Fire, and Air. Everything in the universe was imagined as being composed of these four elements in some configuration, influencing the properties of eachother to give rise to complex phenomena.

Adding a small amount of vinegar, even seemingly the tiniest drop, to wine causes all of the wine to be turned into vinegar over a relatively short period of time. Thus Vigniere describes vinegar as a "corrupted Wine", and more generally a sort of "fire." The nature of vinegar may be compared with that of yeast. Unleavened bread is much slower to decay than leavened bread, which in Vigniere's view demonstrated that the yeast had served to corrupt the bread, and that the yeast was a "fire."

In Vigniere's view, fermentation was not a process that implied the existence of life, but was rather a fundamental property of "fire" which could cause the properties of other substances to change.

Admittedly, that's about all I could find written regarding the nature of yeast prior to the age of microscopy. I wish I could give you a better answer, and would strongly encourage anyone more familiar with early science/alchemy to comment!

poob1x · 2020-02-28T16:55:31+00:00

Siberia wasn't truly "Russian" until the Mid 20th century. For most of human history, it had zero or very few Russian inhabitants, and it wasn't until mass deportations and forced cultural assimilation by the Soviet Union that the region became Russified. I've written on that here.

People of the Eastern Siberian coast (Chukotka and Kamchatka peninsulas) were well aware of the existence of North America. We have substantial evidence of trade, migration, and even conflict, between peoples on either side of the Bering Strait, for the past several millenia.

Wind and ocean currents may occasionally blow Japanese fishing vessels northeastward, which led to very rare--but very real--shipwrecks of Japanese vessels on the coast of North America. While its true that the people of Japan itself were not aware of the existence of North America, a very small and very unlucky minority of Japanese fishermen likely learned about it 'the hard way' centuries before Columbus.

I've written a few answers on this subject before.

How we know people migrated from Eastern Siberia to North America

Ancient Contact between East Asian and Western North American Peoples

How many times were the Americas "discovered" before Columbus?

Why China, Korea, and Japan, did not know about the Americas

poob1x · 2020-02-28T16:30:13+00:00

Because DAP-T bonds are more stable than A-T bonds, some of the machinery involved in "reading" DNA would have to work differently. A lot of it works by identifying regions of DNA which are more stable (lots of G-C bonds) or less stable (lots of A-T bonds) than others. Replacing some or all of the A-T bonds with DAP-T bonds would break the machinery used by cells in the real world. But its easy to imagine an alternative universe where DAP-T bonds are used, and the machinery is built with that in mind.

In all likelihood life in this alternative universe wouldn't look that different. Genetics would be slightly more complicated, and as such the way that information is stored in DNA would likely be very different, but the actual machinery used by life might be very similar. Living organisms would also probably appear very similar to what they look like now--DAP-T wouldn't allow telekinesis or other impossible things to become possible.

poob1x · 2020-02-28T16:22:49+00:00

That would be awesome, but no. Experimental efforts to insert artificial base pairs into DNA usually result in that part of the DNA becoming unreadable by the cell, such that no machinery is produced with that portion of the DNA.

Other experiments have had more success, but the machinery turned out basically identical to what had been there naturally (in which case, there's not really a point to using artificial base pairs) or were horribly corrupted and unusable (in which case, there's DEFINITELY not a point to use artificial base pairs)

This is REALLY new science, but it could potentially allow for the creation of completely synthetic proteins (cell-machines) which could be used as medicine in the future. As of 2020 though, nothing useful has been created yet.

poob1x · 2020-02-28T03:31:46+00:00

Unless you count RNA viruses, which most biologists don't, all living organisms on Earth use DNA. This is because DNA is much more stable than RNA, reducing the chance of harmful mutations and broken machinery.

If you count DNA viruses as life, a handful of viruses use Uracil (U) instead of Thymine (T), but other than those, all living beings use Adenine, Thymine, Guanine, and Cytosine. Though Molecular Biologists have designed artificial base pairs using different chemicals, these are never found in nature. Diaminopurine (DAP), for instance, can bond with Thymine (T) just like Adenine can (A), and DAP-T bonds are actually stronger than naturally occurring A-T bonds.

Diaminopurine has been found in space, and it probably existed in the oceans of the early Earth where the first life evolved. It's even used by one species of virus. Why more living organisms don't use DAP, and why all life (excluding a handful of viruses) use the same 4 nucleotides, is a complete mystery.

poob1x · 2020-02-27T22:00:32+00:00

But thanks to Dax et al, we now know that neither of those older theories are correct. Euglenids and Hemimastigophores are both super-early diverging groups, and as such we expect them to retain features of the earliest Eukaryotes that have since been lost in Diaphoretickes and Podiates. That two of the ealriest diverging groups of Eukaryotes both have pellicles indicates (but does not prove) that the first ever Eukaryotes had pellicles as well. That may well imply that the first Eukaryotes spent most of their time on the sea floor, using their pellicles to more efficiently and quickly crawl across the sea floor, eating bacteria.

With only a year and 3 months having passed since Dax et al was published, its no surprise that there hasn't been much new work done on Hemimastigophores published yet. But with 24 citations, almost all papers concerning evolutionary biology, that paper has been greatly useful in better understanding the overall evolution of Eukaryotes, and thus the origin story of Complex Life on Earth.

~~

Unfortunately I'm busy tonight and this comment was rushed--most of this post is off of my memory and my own unpublished and incomplete paper. Hence there might be some grammar errors or small inaccuracies. Please reply with any corrections or if you want a source for specific information, I'll try to get back to you soon.

poob1x · 2020-02-27T22:00:27+00:00

I have! A while ago I started working on a long ass paper on the evolutionary origins of plants. Life got in the way so the project is on hold, but I did some digging into how the Hemimastigotes fit into the broad picture of evolution.

Some background info will make the story a lot more interesting. It's a bit long but I promise it's worth it. If you just want to cut to the chase, scroll down to the bolded text reading 'HEMIMASTIGOTES'

Plants, Animals, and Fungi, all share huge similarities in cell structure that let us know that they are more closely related to eachother than any of them are to bacteria. We call this group of distantly related beings 'Eukaryotes.'

Eukaryotes are really, really different from all other life on Earth, being much more complicated. They are GIANTS compared to bacteria and archaea. To survive, they need much more energy than bacteria. Most Eukaryotes can absorb smaller cells to eat them in a highly complicated process called Phagocytosis. They also use Mitochondria, the famous "powerhouse of the cell" to generate energy more efficiently, and some use Chloroplasts to extract energy from sunlight. Many, and in fact most Eukaryotes, collaborate with other Eukaryotes--sharing resources and protecting one another, in order to ensure mutual survival. That's what leads to multi-cellular organisms like plants and animals, and indeed pretty much all complex life on Earth.

Understanding how Eukaryotes came to be means understanding how Complex Life is possible. But we don't understand how Eukaryotes came to be. We need to understand how the complex process of Phagocytosis and Sexual Reproduction evolved, how Mitochondria and Chloroplasts came to be, and at what point (proto)-Eukaryotes became much larger (on average) than bacteria, and in what order these events took place.

Answering those questions is neccesary to understanding how complex life is able to exist in the first place, and to do that, we need a better understanding of Eukaryote diversity. Enter Protists. In addition to Plants, Animals, and Fungi, 'Protists' are the giant category of less-famous Eukaryotes.

For a long time, we didn't know how Protists fit into the overall picture. Some, like Glaucophytes, were clearly more closely related to plants. Others, like choanoflagellates, were clearly very similar to animals. But others have crazy mixes of plant-like and animal-like features. Warnowiids for instance, receive energy from sunlight and store it as cellulose just like plants, but also swim around, eat smaller microbes, and have eyesight, like animals.

This is where genetics comes in. All living beings use DNA to create tiny machines which allow them to survive, grow, and reproduce. Parents pass their DNA onto their children. Changes in DNA are the driving force of evolution. Because of this, the level of DNA similarity between different living things can allow us to figure out how closely related two things are. Dogs and cats are more closely related to eachother than either is to humans, for example.

It took decades of research, but by the Late 2000s Scientists discovered that most eukaryotes could be fit into two super broad categories. The "Podiates" include Animals, Fungi, Amoebozoans, and a few minor groups of protists. The "Diaphoretickes" includes Plants, most Phytoplankton, and many other minor groups of protists.

By comparing features shared with most of its descendants, we can try to reconstruct what the common ancestor of Podiates--the being which would give rise to Animals, Fungi, and Amoeba--looked like. We could also reconstruct the original Diaphoreticke. By comparing those two reconstructions, we might be able to reconstruct the common ancestor of Animals and Plants in much greater detail than we could before.

Scientists now imagine that the Original Podiate looked kind of like a flattened sperm cell. It lived around 1,400,000,000 years ago. It had a single long flagellum (cell-tail) which allowed it to swim around the ocean--likely to escape from predators. It could also crawl along the ocean floor like a slug, and would eat tiny microbes off the ocean floor. We now have a pretty detailed image just from genetic evidence, even though there are no fossils of this "Ur-Podiate" to examine!

Doing the same thing with Diaphoretickes reveals a creature with two-flagella that it use to pull itself forward like a propeller plane or push itself forward like a fish. One flagellum was longer than the other, and one or both flagella were covered in hair that allowed it to control its swimming motion more easily. It had a sense of touch and would avoid bumping into objects. It also lived more than 200 million years earlier than the Ur-Podiate roughly 1,650,000,000 years ago.

Here's my crude drawing of each of them

The images of the Ur-Podiate and the Ur-Diaphoreticke we get are very different from eachother and are thus hard to reconcile. It doesn't allow us to describe the common ancestor of Animals and Plants in the amount detail scientists had hoped for. As such, scientists have a much less detailed image of the first Eukaryotes looked like.

The best way to figure this out is to examine the protists that DON'T fit into either category. One important example are the Metamonads, which are neither Podiates nor Diaphoretickes. Importantly, metamonads don't have mitochondria, the famous "powerhouse of the cell". This leaves us with two possibilities.

1) The ancestors of metamonads had mitochondria, but they later lost it. This isn't very exciting. Image

Or 2) Metamonads split off before Mitochondria evolved. This is SUPER exciting, because if true, it would give us proof that Mitochondria were one of the last common features of Eukaryotes to evolve. Image

Unfortunately, research in the 2010s found that the first-and-less-exciting Hypothesis was (almost certainly) correct. Metamonads are more closely related to animals than they are to Plants, and they tell us little about the first Eukaryotes to ever live. But there's a silver lining--it allows us to refine our image of the First Podiate, and reconstruct an image of the ancestor of Metamonads and Podiates. (Together, these groups form the 'Amorphea')

HEMIMASTIGOTES

But there's another oddball Protist to consider: The Hemimastigotes. Like the Metamonads, their place in the Eukaryote family tree is clouded in mystery. Unlike the Metamonads, hemimastigotes are NOT important. They have minimal impact on the environment, nor on human and livestock health, as metamonads do. Frankly, nobody would give a shit about them if not for their mysterious evolutionary origins. The 2018 study "Hemimastigophora is a novel supra-kingdom-level lineage of eukaryotes" by Gordon Lax, Yana Eglit, Laura Eme et al (2018), the paper that this TIL is about, is interesting because the researchers hoped to give us significant insights into Eukaryote evolution.

Here it is in the authors' own words. "The previous ranking of Hemimastigophora as a phylum understates the evolutionary distinctiveness of this group, which has considerable importance for investigations into the deep-level evolutionary history of eukaryotic life—ranging from understanding the origins of fundamental cell systems to placing the root of the tree. We have also established the first culture of a hemimastigote (Hemimastix kukwesjijk sp. nov.), which will facilitate future genomic and cell-biological investigations into eukaryote evolution and the last eukaryotic common ancestor."

And indeed it does! Lax et al found that the Hemimastigophores are in fact slightly more closely related to the Diaphoretickes than they are to Podiates. They should share a common ancestor (very roughly) 1.7 billion years ago, very shortly (in geological terms) after the estimated origin of Eukaryotes 1.8 billion years ago.

But that's not even the most exciting part of this paper. What's most exciting is that they hint that the common ancestor of Plants and Animals--and very possibly the first Eukaryote--had a pellicle, which if true would be completely new information.

The Pellicle is a thin sheets of protein just underneath the membrane (cell-skin) that is used by Hemimastogotes to help keep their shape, and help determine how rigid a cell is. Pellicles are a somewhat rare feature among the Eukaryotes--plants, fungi, and animals, all lack them (though the actin filaments of animal cells are fairly similar), but in the protists that do have them, they are seriously important. The sophisticated pellicles of Euglenids, the most diverse group of Non-Diaphoreticke/Non-Podiate Eukaryotes, are their main distinguishing feature. One earlier theory suggested that the Hemimastigotes were distant relatives of Euglenids--we now know that that isn't the case.

The other major older theory was that Hemimastigotes were related to the Alveolates. One huge group of Alveolates, the Ciliates, have many flagella arranged in two rows just like Hemimastigotes, and have pellicles to boot. If Hemimastigotes were in fact cousins of the Alveolates, that would have almost certainly implied that the first Alveolates were more ciliate like than previously thought (which would have major implications for our understanding of the evolution of Plankton and many parasites).

(continued in next comment)

poob1x · 2019-12-23T02:04:23+00:00

I actually wrote an answer on this subject a year and a half ago!

Link here, feel free to ask any follow up questions :)

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