Transcription
Hey there guys, sorry for the long wait. You know me and my extended absences.
Today, I've got a treat for all you guys because in this video, I'll discuss in depth and debunk some myths associated with a topic I'm pretty certain most paleontology or crypted fans have heard of. Living fossils is a name frequently in reference to animals that are alive today but seem to be apparent in the fossil record with their prehistoric counterparts being virtually identical to their modern ones. The common examples are crocodilians, sharks, horseshoe crabs, mantis shrimps, triops, Nautilus, and the most famous of them all, a type of bony fish called coelacanths.
A ton of misinformation surrounds these animals, and often they are misused to promote pseudo science agendas such as cryptozoology and creationism. Ever since I've been introduced to the crypted community and studied the late surviving dinosaur, *parasaur*, or *plesiosaur* phenomena, I've been consistently met with a common argument whenever either I or someone else questions how giant reptiles surviving the KPG mass extinction could have evaded discovery in the fossil beds after the age of the dinosaurs. Surely, I say, we would have discovered some evidence of dinosaurs or *pterosaurs*, or whatever, in the fossil record after the Cretaceous by now. Surely, we should have discovered the fossils of mammoths or humans alongside *sauropods* and *Tyrannosaurs* if they really coexisted alongside one another.
The response I get typically goes like this: "Living fossils, the coelacanth, crocodiles, horseshoe crabs, sharks, and mantis shrimps haven't changed in millions of years since prehistoric times and coexisted alongside dinosaurs, yet survived. Coelacanths were once thought to be extinct around the same time of the dinosaurs and have no fossils after the KPG, but they were discovered to still be alive. Clearly, dinosaurs are still alive out there somewhere, all over the place."
I see people saying, "Coelacanths, the fish that refused to evolve," or "Coelacanths disprove evolution," or "Living fossils prove dinosaurs and humans coexisted." Muslim creationist Harun Yahya says, "Countless living fossils have remained unchanged for millions of years, and their current anatomical structures are exactly the same as they were millions of years ago. The fossil record is almost complete with both animal and plant specimens demonstrating this. It definitely and scientifically refutes evolution."
Here's an interesting gem from creationist Ken Ham's Answers in Genesis website: "Now, here's a point: no fossils of coelacanth have ever been discovered in the same layers as human fossils. I'll address this later, but they have been found in the same layers as dinosaur fossils. Yet, we know coelacanths and humans do live together because they do so in the present world. In other words, just because we don't find fossils of certain creatures or plants together with humans in the fossil record, it doesn't mean they didn't live together." This logic is mistaken, but I'll explain that later.
Or this one, I believe from the Creation Museum: "What I'm trying to say is, in other words, the situation and information surrounding the topic is a mess, and I think needs to be addressed properly by actually looking at what the scientific evidence says." Living fossils are surrounded by great misunderstanding, and most of the time, people using them don't know all the information about them or even a good understanding of the topic they're saying they just prove. Or prove, almost always, you'll see living fossils misused to prove proven (big quotation marks) one of all three things:
Number one: that these animals haven't evolved over millions of years and thus evolution is disproven by their existence.
Number two: that their existence proves dinosaurs and other extinct animals are still living today, virtually unchanged since the Mesozoic.
And lastly, number three: that is in the case of coelacanths, the fossil record has massive gaps or is unreliable, and dinosaurs that survived the KPG mass extinction either fail to fossilize or are hiding in the fossil record somewhere, and that is the reason why dinosaurs and other *yada yada* coexisted with humans without evidence of that being so in the fossil record.
The usual suspects are creationists, and man, do they love to talk about these guys. You name it, Christian or Muslim, almost all creationists use living fossils to try to prove one, if not all, of those things. I think it's about time someone puts some science up in this thing, so I'm going to look at all the scientific evidence from scientific journals and papers and see if any of these points are actually valid.
All right, let's address the first claim: that living fossils don't exhibit evolution over millions of years and as a result disprove evolution exists. It's funny when creationists bring this point up, as Charles Darwin himself was the one who first coined the term "living fossil," and in his usage of the word, he explained perfectly why something like this should exist in accordance to evolution. In *On the Origin of Species*, when referring to several species of freshwater fish such as lungfish, which are related and resemble the *fish-like* ancestors of all tetrapods, Darwin explained that "these anomalous forms may also be called living fossils. They have endured to the present day from having inhabited a confined area and from having thus been exposed to less severe competition."
Let me explain what Darwin said here. It's not that such animals have stopped evolving or haven't evolved at all since prehistoric times. It's that these animal populations have only evolved at a slower rate than other animal populations. The important thing to remember about evolution is that the rate at which it goes is relative to the environment an organism population is in. Some environments with very competitive selective pressures will force organisms to evolve at a rapid rate, while ones with less selective pressures will contrastingly slow the rate of evolution.
Evolution at its core is merely a game of population genetics. In an organism's population, specific genes are favored over other genes. This is decided by selective pressures in the environment, such as predators, the ability to access food, and the ability to mate with another of your species. Natural selection blindly weeds out genes that restrict an animal's ability to reproduce in favor of those that more effectively allow an animal to reproduce. Gradually, over several generations, the only genes left in a population are those that are most effective in allowing an animal to reach reproductive age. Eventually, an animal population will reach a point where natural selection has refined the population to the point that the population can refine itself only minimally. That's right, evolution basically works like this: if it ain't broke, don't fix it.
If a population does just fine in the niche or role it has in the environment currently, and the environment is stable with very little change, then selective pressures will lessen, and the population will only favor traits already shown to be successful, thus slowing the rate of evolution. This phenomenon is called stabilizing selection, which is the continuation of natural selection favoring the pre-existing body plan. The process occurs when basically an organism has become so perfectly evolved for a job, and the environment has stabilized, that the population has no need to change beyond what it already had. This is especially true for animals listed as living fossils, as their roles in the environment are relatively constant throughout history. This is why you'll often find living fossils either lower at the food chain, such as coelacanths and horseshoe crabs, or as more opportunistic species that are jack of all trades, such as sharks.
Anyways, the concept of stabilizing selection does not at all disprove evolution because evolution by natural selection continues, as it still weeds out genes that make an animal unfit. There's just no reason for these animal populations to deviate far from the standard in their environment based on their selective pressures. So, that's right, Darwin already addressed the problem before creationists could even have a chance to bring it up. But still, creationists act like he and other biologists completely have no idea about living fossils.
Additionally, let me address that even in these living fossils, one can easily exhibit that evolution has taken place. There are clear differences between the extinct variety and the modern variety of every living fossil on the list, illustrating evolution has occurred in such animals, however slight or massive they are, depending on the animal. Let's talk about the most common one creationists use: the coelacanth. "The pretty comedically named scientific paper *Coelacanths as Almost Living Fossils* and why coelacanths are not living fossils." Examine some of the many evolutionary differences between the extinct and extant, still living, coelacanths. One can easily see the morphology and body structure of extinct coelacanths differs greatly from contemporary ones. The extinct varieties took on a great diversity of shapes and sizes, illustrating these animals once filled many different niches in the prehistoric environments, and the only two still surviving species represent an only pitiful remnant of their once large role over the ecosystems of Earth.
The paper *Coelacanths as Almost Living Fossils* even concludes by saying, "Although living fossils are obviously not non-evolving organisms, they gather an informal group of slowly evolving organisms. We agree that the term 'living fossil' may affect the understanding of evolution, especially by non-professional biologists." There are many other scientific papers that point out that all the other popular living fossils have evolved since their prehistoric days. Horseshoe crabs are commonly paraded as being just like coelacanths, completely unchanged for millions of years. However, the also perfectly named paper *Horseshoe Crab of Genus Limulus: Living Fossil or Stem-Group Eutardigrade?* states, "Horseshoe crabs that are only found in modern ones." The authors, just like those of the coelacanth papers, believe the term "living fossil" is inappropriate and often gives an inaccurate view of such creatures by suggesting they haven't evolved at all. They prefer the term "stem-groups," animals that simply show a slower rate of evolution. Crocodilians, sharks, triops, mantis shrimps, etc., all exhibit similar differences between fossil and modern species. Basically, universally, the scientific papers advise against the term "living fossil" as it is misleading. Such as one on triops explains, "Our work shows that organisms with conservative body plans are constantly radiating and presumably adapting to novel conditions. I would favor retiring the term 'living fossil' altogether as it is generally misleading."
To answer some creationists, they are most definitely not exactly the same. They are not entirely unchanged by millions of years, and even if they were, that wouldn't disprove evolution at all. So, in short, no, living fossils certainly do not disprove evolution. They actually always have been able to prove evolution, and this has been true since the conception of evolution by Darwin himself.
Moving on, I'm going to combine numbers two and three as they often go hand in hand with one another. These two usages of living fossils are the ones that have surprisingly seen are not limited to creationists, as many non-creationist cryptozoologists and other people, but you know, often use them as arguments to prove the existence of late-surviving Mesozoic reptiles such as *pterosaurs*, dinosaurs, and *plesiosaurs*. The common casualties of this argument are again coelacanths and crocodiles, as most proponents of late-surviving extinct *yada yada* point to them as evidence that such animals still could be around and additionally remain elusive in the fossil records after the apparent extinction during the KPG mass extinction. In other words, living fossils are used to explain away why we never find a T-Rex gobbling up a primitive horse or a *plesiosaur* swimming side by side with a whale preserved in any of the many younger geologic layers after these animals' disappearance from the Earth entirely.
In response to number two, we've already explained why it's not really significant that some holdouts from the time of the dinosaurs are still alive today, relatively unchanged since the olden days. They were able to keep a meager existence while other animals became extinct. One might as well try to say because Bill Gates is still alive today and coexisted with *Mao Zedong*, then *Mao Zedong* is still secretly still alive, even though we have direct evidence in contradiction to that and a massive lack of evidence to show the contrary. It's pretty ridiculous. It's certainly possible such animals could still be alive today, just like how late survivors from the Permian like *Scutosaurus* and *Dicynodonts* survived late until the dinosaurs' day in reduced populations. Non-avian dinosaur, *pterosaur*, or *plesiosaur* late survivors could have survived into our day in reduced populations as well. However, let's forget what is possible and focus on what is plausible and supported by evidence. Do we have any reason whatsoever, besides a few scattered eyewitness claims, that such organisms are still alive today? Well, no, we don't. Of course, absence of evidence is not evidence of absence, but that doesn't mean absence of evidence is evidence either. That's a mouthful. By just saying the possibility is there is evidence of something's existence, that is the logical fallacy of argument from silence. By that logic, I could easily say Darth Vader exists somewhere out in space because space is so vast and you can't prove he doesn't exist.
Well, anyways, the fossil record simply doesn't give credence to late-surviving Mesozoic fauna, in contradiction to what many cryptozoologists and creationists claim. Sure, Mr. Ham, it doesn't disprove that these animals didn't live alongside one another, but it doesn't prove that they did either. Do I really need to bring up Darth Vader again?
But what about the coelacanth? "Say it is no evidence that it survived the KPG mass extinction but was still found alive today. Clearly, other animals could be resurrected from being classified as extinct too." Well, my humble straw man, that's what I'll address. Number three: proponents of late-surviving *yada yada yada* use living fossils, specifically the coelacanth, to prove that the fossil record has gaps in it that make it unreliable for telling if an organism really is extinct. And to some extent, this is true. The fossil record is full of gaps. Online, you'll be able to find a list of many organisms that have a very, very spotty fossil record, which sometimes has vast amounts of time between fossilized remains. However, it is crucial to understand that this spotty record is not universal to all organisms. The fossil record is in fact very biased to certain organisms, and sometimes it favors the preservation of some animals over others.
The reason the fossil record on some groups are so scarce while others is extremely rich is because of the rarity of fossilization and how the process occurs. The process of fossilization occurs very rarely and in very specific conditions. For an organism's remains to become a fossil, it must be quickly covered with sediment so that scavengers or the elements don't destroy it instantly. This is why fossils normally form in riverbeds or at the seafloor, areas where silt or sand can cover the body before it can fully decompose. In this process, soft tissues such as organs and skin are normally lost to decomposition, only leaving hard structures like bone. As a result, organisms with hard body parts fossilize more often than ones with entirely soft body parts. Additionally, the harder and more durable your remains are, the more likely they are to be fossilized. This is the reason why we have a hard time finding the cartilaginous skeletons of sharks in the fossil record but have a very easy time finding their calcified teeth. This is additionally the reason why coelacanths are especially spotty in their appearance in the fossil record. The bones of coelacanths are fragile, small, and subsequently have a low potential for preservation, in addition to them being ever increasingly rarer even before the dinosaurs became extinct and difficult to identify even by some of the most skilled paleontologists. One can spot why scientists prior to their rediscovery during the 1930s didn't have any fossils to show were still alive after the dinosaurs, and this is really going to blow your guys' minds.
Even with the extremely low potential for fossil preservation, we have successfully discovered the fossilized remains of coelacanths between the KPG and now. A Swedish Paleocene coelacanth and a Miocene coelacanth have since bridged the gap, meaning the 60 million-year-old gap boasted by creationists no longer exists, like, at all. Even so, do dinosaurs and other extinct reptiles suffer from the same issues of lack of preservation? A coelacanth certainly not. This is why using the fossil record of coelacanths as an analogy to the fossil record of post-mass extinction dinos simply doesn't work. Reptiles have strong calcified bones, just like us, which has allowed them to have a very detailed fossil record as they preserve often. We should instead, based on dinosaur, *pterosaur*, and *plesiosaur* body structure and anatomy, use the fossil record of birds and crocodilians after the mass extinction as a much more adequate comparison. We've found thousands of crocodilian and bird fossils between the dinosaurs and now. The fossil record after the Cretaceous is by no means poor; it's probably just as rich, if not richer, than the previous periods, and as a result, we've been able to find literally thousands of tiny evolutionary transitions from that period to now, but not any dinos.
If there are post-KPG dinosaurs, *pterosaurs*, or *plesiosaurs* left undiscovered in the fossil record, they are hidden much better than an extremely rare type of fish whose bones seldom fossilize and whose remains are not as easily identifiable by scientists as those of any dinosaur or *plesiosaur*. It's almost as if there weren't any of those creatures because statistically, we should have found them by now, long before we should have discovered post-KPG coelacanths. So, it's gotten to the point where either non-avian dinosaurs and similar reptiles became extinct when they disappeared in the fossil record, or paleontologists are just extremely unlucky as these animals have evaded being fossilized in every single fossil formation since the time they disappeared. Thus far, you think that since we have found everything from fossilized spiders, fish, and insects from those periods, we would have at least found just one, just one dinosaur, if they coexisted with them, but we don't. This is why people like zoologist Darren Naish call coelacanths red herrings. They don't accurately represent the fossil record of dinosaurs or what have you because they are so different in their fossil preservation. So please, stop using them in this manner.
In summary, living fossils don't prove dinosaur and man coexistence, and just because the fossil record of some animals is spotty due to preservation factors, that doesn't prove dinosaurs are miraculously evading fossilization too. I must reiterate that the animals often referred to as living fossils deserve better treatment than to be used for a divisive means, such as to promote religion or to promote pseudo science. These animals give us an interesting insight into everything from the mechanics of evolution to the ins and outs of fossilization. I think we should maybe stop calling them living fossils and maybe give them a better, more accurate name that respects what they are: the evolutionary slowpokes. I've been Trey, the Explainer, and thanks for watching.
Hello there guys, I hope you enjoyed my longer video. I spent a ton of time researching and investigating this topic, as I was often met with these arguments and I really didn't know how to respond until recently. Maybe if you guys encounter a similar problem, you can just link people to this video as an easy response instead of writing and explaining it all out. Next time, I plan on finally finishing my Loch Ness series, and after that, I plan to talk about islands with very unique biodiversity, including some from ages long ago. Okay, see you.