Rapid Evolution

Hey guys, and welcome back to another episode of Trail Explainer. Now, before you get mad at me, I'm just gonna say it. I already betrayed my 2018 schedule for my last video a bit. And if you know me, I get super distracted very quickly, and I often find stories I find interesting that I really want to do a video on. Where does it learn about them? And just to tell you, this is one of those video ideas.

Since the last video, I'd like to make two additions to my plans: a video about how scientists date the age of the Earth, and this video right here. The biological process known as evolution by natural selection can often seem to most people as this abstract and vague thing that can't really be seen or directly observed. And I've had a significant amount of my audience doesn't really believe it exists because of this, among other things. Well, in this video, I'd like to highlight a few discoveries over the years and hopefully show or illustrate that this image revolution is the slow and visible process that takes millions of years to occur is in fact not entirely accurate, and discuss the actual evidence that shows evolution is very much a visible phenomenon that can occur within our lifetimes and we can observe with our own eyes, with the hope of convincing some people who really don't believe it occurs or can occur.

This video is about rapid evolution examples, in which organism populations have changed significantly with new species forming in just a few decades. The Big Bird's. Almost anyone who is the least bit acquainted with Darwin or evolution has heard of his travels to the remote Galapagos Island chain and his experiments with various unique animals which exclusively called the islands home. From studying these islander animals, Starwood noticed some odd things about them. By studying mainly the finches present on these islands, he found that the animals on the islands possessed what he called a plain staff of affinity to those created in America, or in other words, were pretty much almost identical to those found on the mainland. But he found that this affinity was not entire, as most the animals on the islands differed slightly, not just from their mainland counterparts, but from each other. As suspiciously in accordance to their diet, famously using the slightly fluctuating shapes and sizes of the beaks of the finches, Darwin hypothesized that the reason why these island finches shared so many similarities between each other and with ones on the mainland was because that all these benches shared a common origin. In the islander finches were in fact the descendants of colonists from the mainland. While some finches remained on the mainland, these finches, forced to live an entirely alien environment, had to adapt to consume different food sources. The descendants went about this differently, specializing in different food sources. These descendants split up and grew more and more distant as the generations wore on and eventually ended up as different species. This is what is called speciation, when two organism populations formed into distinct new species. And this concept, among other things, forms part of the basis of a Darwin's theory of evolution.

Now, about a hundred years after Darwin's expedition to the islands, British biologist couple of Princeton University, Peter and Rosemary Grant, were not inclined to accept Arwen's theories and experiments blindly and decided to go the islands to really see if evolution was directly observable in the finches. The two chose the minuscule and lonely island of Daphne Major as the stage for their researched. Daphne Major's remoteness in size allowed the couple to avoid human intervention and permitted them to measure and examine almost all of the finches that called the island home. With limited variables, like whether the island was additionally prone to seasonal changes from heavy rainy periods to periods of great drought, these environmental changes would doubtlessly bring changes to the food sources of its inhabitants, and thus the couple would be able to see if natural selection was in fact occurring.

After much planning, in 1973, the Grant set out to Daphne Major for their two-year study. They spent six months under less desirable conditions on the island, catching, measuring, tagging, cataloging, and taking blood samples of almost every Finch on the island. Even for its small size, the island was home to 13 different species of Finch, specializing in different food sources: five tree finch, one Warbler Finch, one vegetarian finch, and six ground Finch species. From their research, they found that just in the first two years of their study, the islands finches changed rapidly through natural selection in response to environmental conditions on the island. During a drought or heavy rainy period, when certain beetles or seeds or more numerous or more scarce, the size and shape of the finches beaks would adjust in response, and when favorable or unfavorable conditions returned, they would change back. Their 2 years study became one that continued up until 2012. Every year, the couple would spend six on the island, despite it being absolutely miserable, and the research they conducted henceforth would only further prove their hypothesis.

For instance, in 1977, when the island was struck with a massive drought causing a food storage of smaller seeds, only leaving larger, tougher seeds, the Finch species with smaller beaks, more adapted to eating smaller seeds, struggled with many of them dying out rapidly. However, the finches with larger beaks prevailed, able to consume the remaining seeds. The repercussions of this event have been clearly seen in the years after 1977. The bigger beak birds surviving the drought were able to reproduce the following year and produce more offspring than the largely devastated birds with smaller beaks. The beaks of the birds after 1977 were measurably larger than those of the previous year's, and just a couple of years, the population had evolved.

However, even these discoveries would be later dwarfed by the arrival of a newcomer. While conducting their annual research in 1981, the Grants encountered and as of yet unseen interloper, a newbie to the island, appearing almost out of nowhere. A single individual that was wholly different and distinct from the other finches native to the island. This new Finch, a male, distinguishable from others due to as unique call, extra glossy feathers, and larger size, was the sole member of his kind on the island. Later genetic studies taken from his blood found that this invader was a traveler from a distant land, loaned to Daphne Major, likely from a storm. He was a member of a known species, the cactus Finch, and has originated from an island 100 kilometers or 62 miles to the southeast, Hispaniola Island. The Grants called him Big Bird due to his larger size than the other ground finches on the island. Big Bird had a much more varied diet than the other birds on Daphne. He could eat both large and small seeds, nectar, pollen, in the seeds of the cacti. Big Bird flourished on the island and never left, and by the mating season, he was able to attract to females of one of the other native species of Finch on Daphne. The mating, although occurring between two different members of two different species, produced offspring, hybrids, non like loggers and mules. Hybrids occur incredibly rarely in the wild, as most of the time species tend to only breed within their own species. But Big Bird was an exception. These hybrids shared characteristics of both their parents, even retaining the unique call their father. Surprisingly, unlike most hybrids being sterile or unable to reproduce, these hybrid finches were fertile. The one catch was that these children of Big Bird, on account for the distinct appearance, mating call from the resident Birds, traits crucial to attract new mates, would only find each other to mate with Big Bird's hybridize offspring. Inbred. This aim breeding produced what would be called the Big Bird lineage. This new type of bird, the offspring of hybrids, the Big Bird survived over the years on the island and continued to reproduce only amongst themselves, isolating them genetically from all the other Finch species on and off the island. The Big Bird lineage grew bigger and bigger until when the new lineage was on its fourth generation, a series of droughts struck the island from 2002 to 2003. This drought devastated the Big Bird population. Almost any in the family line of the original Big Bird patriarch, who died almost a decade prior. When the rains finally came, only two Big Birds remained, and it seemed the family line would undoubtedly end here. But the Big Bird family was persistent. The two mated and produced 26 offspring, 17 of which survived to sexual maturity. These survivors broke all the rules in order to survive. A daughter mated with her father, a son with his mother, the rest with their brothers and sisters. Although horribly inbred, the Big Bird lineage was saved and managed to not only survive but eventually start to thrive in their environment, even with their incredibly limited gene pool. At the present, it doesn't seem to impact them that much, as they have been ecologically successful, and even after 30 years, the Big Birds have continued to only mate amongst the other descendants of the original Big Bird.

In 2012, the Grants counted 23 individuals and eight breeding pairs of the lineage, and a subsequent return to the island in 2017, with the birds in their seventh generation, showed that the Big Bird lineage could now be classified physically and genetically as its own separate species from any other Finch. Big Bird serves as one of the many events in which scientists have directly firsthand observed evolution, more specifically speciation, that is, evolution of a new and distinct species. The Big Bird lineage has become the Big Bird species, as a geneticist puts it. A naturalist who came to Daphne Major without knowing that this lineage arose very recently would have recognized this lineage as one of the four species on the island. As it turns out, the Big Bird lineage has reproductively isolated themselves to the point they were our different species, and this has happened only within a few decades. We have witnessed a new species evolving right in front of us, entirely naturally. To this day, they are still singing their unique call on the island and only mating with fellow Big Birds, and it is likely they will continue to do so into the future. If this lineage of this individual continues as is, its distinction from the other finches of Daphne will continue until it is virtually indistinguishable as descendants of hybrids from any other species. We have no idea on the longtime survival of the Big Bird species. They could easily lapse back into extinction, as they almost did in 2003. But based on how quickly the Big Bird lineage has taken root and evolved, we can infer that events like this, the evolution of distinct and unique lineages, have occurred entirely naturally countless times over millennia. The vast majority of these lineages went extinct and became entirely forgotten, but it is also likely a few actually survived and were able to continue to exist as unique populations, eventually, like the Big Birds, becoming the distinct species of finches we know today on Island. This is how evolution works in baby steps. Odds are all the species on Daphne and all the species throughout the Galapagos Islands started out like the Big Bird. Who knows? The ancestors of humans, as distant to us now as a dream, mine of first diverged in a similar manner, emerging as a small family lineage formed by a sheer queer individual who served as the foundation for their new and unique line, and that against odds survived and Mitchellly became so isolated that the population became its own species. And that means you probably definitely were a product of incest. Add that to my list of Trail Explainer quotes.

The Italian wall lizards, another interesting example of rapid evolution that was directly observed by scientist, is that exhibited in the Italian wall lizards of Pod Macario. Italian wall lizards are species of incredibly diverse reptiles that live in countless locations across the Mediterranean, from the mainland to the hundreds of islands littered across the sea. There are dozens of unique subspecies that have adapted to the many locations in which they are found. A single small Italian island, for instance, is said to be the exclusive home of a uniquely blue-skinned subspecies. This wide range of adaptability and versatility made these lizards, much like the finches of Daphne Major, the perfect test subjects.

In 1971, scientists created an expiry involving the wall lizards. 10 adult individuals were taken from their native Coasian island of Pod Capacity to the similar but distant Island of Pod Mikaru, only a few kilometers to the east. In fact, islands are so close that they can be viewed from one another on the horizon. After the scientists have brought the lizards to the island, replicating the similar conditions of immigration by a natural storm or drifting event between islands, all they had to do was wait and see what happened to this population of immigrants. The island was additionally devoid of all humans, so the scientists need not worry about any human interactions. These imported lizards rather quickly flourished in the new environment, as Mikaru had nearly identical conditions to their own land. The Italian wall lizards did so well that they outcompeted the unfortunate native wall lizard species on the island, which are now locally extinct. However, it wasn't until return to the island decades later, in the 1990s, that something truly extraordinary was revealed. Scientists upon the return found that the wall lizards of Mikaru were very different from their cousins on Campus T. DNA analysis showed that these wall lizards were in fact the very descendants of the ten lizards that had been brought to the island three decades prior. However, as the scientists found, much like the descendants of Big Bird, these descendants had fundamentally changed biologically and anatomically over the generations in response to their new environment. Even just physically, the lizards could be exhibited as changed. They were on average larger, had shorter hind limbs, and were slower when sprinting. Additionally, their heads were on average longer, wider, and taller, and had increased bite force compared to their Capacity ancestors. But most notably was the change in the lizard's diet. Unlike their ancestors and the cousins from Capacity, which fed primarily on insects, these lizards ate a much more significant amount of vegetation and plant matter. The larger, wider, and longer heads, increased bite force, was likely a result of this change in diet. But most interesting of all was a further, far less visible, but nonetheless crucial difference between the descendants and their ancestors was the presence of cecal valves in nematodes in the Mikaru populations. Cecal valves are intestinal structures which basically form fermenting chambers which slow down food passing through in animals and test ins, allowing most notably plant matter like cellulose to be further broken down and digested of its nutrients by microorganisms. These gut structures are very helpful to an animal that consumes a lot more plant matter. Sico valves are incredibly rare, only occurring in less than one person of all known reptiles, so it was a massive surprise to find cecal valves in the guts of these Mikaru lizards, which was entirely lacking their Capacity ancestors. Furthermore, scientists found nematodes living the guts of these lizards, having a mutually beneficial cooperation with the lizards by helping breakdown plant matter that passed through, which again was and is entirely lacking in the lizard's Capacity counterparts. As it turns out, the wall lizards on the island very clearly acquired new traits not held by their ancestors, entirely naturally and on their own through evolution, in order to adapt to Makar's more vegetarian diet. The lizards, in just a few decades, had evolved brand-new adaptations not held by their ancestors through mutations in natural selection in response.

Three-spined stickleback. Lake Washington, near Seattle, in the 1960s, was a cesspool filled to the brim with sewage and murky algae blooms. Human pollution had turned the lake into a disgusting mess that rivaled that exhibited in Dr. Seuss's works. Even so, the lake was home to a very hearty type of fish, sticklebacks. Sticklebacks are a very numerous type of small fish and are often called the cockroaches of the fish world, and with a name like that, it's no surprise that they were able to survive this period in history. Thankfully, a 140 million dollar cleanup effort was made to clean up Lake Washington during the mid-1960s, and this effort paid off, as the lake now was clean and beautiful as it once was centuries prior. This cleanup effort, however, sparked something interesting when scientists examined how this effort affected the stickleback, so it's called at home. As it turns out, the sticklebacks changed their physical appearance, in particular their armor plating, in response to the cleanup and notably the transparency of the lake water. Back during the height of the pollution, one could scarcely see deeper than 30 inches under the water. This thick and murky water was surprisingly beneficial to the sticklebacks, as it provided some cover for them from their mini predators. A scientist found the fish during this period were very minimally armored, often lacking and productive bony scales or plating, as they had little need for it. This all changed when the water became progressively cleaner and cleaner, as protective armor was once again needed, as the sticklebacks were now easier to see for their predators, and now the transparency is approaching 25 feet. This change in water clarity is directly correlated with the armor present in the sticklebacks. In the late 1960s, only about 6% of the lake stickleback population was completely armored, but today that number sits at a whopping 49% fully plated and 35% as partially plated. As the lake became clearer and their environment changed, the sticklebacks of often response, although in this circumstance, the evolution is response to human intervention. The process in which this analyst change is entirely natural and would have occurred if the lake cleanup was due to humans help or the elements.

These recorded events are just a few of many, and they clearly show that life can and does change and evolve through the process of natural selection. Organisms can become new species and acquire new traits wholly on their own and through natural processes without intervention or creation needed. All they need is time, reproduction, and a change in their environment to instill evolution, and the rest is handled entirely naturally. Although such experiments seem trivial or irrelevant to the untrained eye, the case of the Big Bird, in the sequel valve lizards, and the sticklebacks is one of crucial importance to scientists, as these directly observed events give us an amazing insight to how evolution works firsthand, and especially how rapidly evolution can occur. These relatively quick changes occurring over a minuscule amount of time stand as a testament to how much life can evolve and change over hundreds, thousands, hundreds of thousands, and even millions of years, with thousands of generations as opposed to only a handful. These relatively speaking baby steps that we can see today can doubtlessly give rise to major changes when these little changes build up over countless generations. A finch population with a slightly different beak could easily continue to refine and specialize their bodies for their specific skills through evolution and eventually end up as something that wouldn't resemble their ancestors in the slightest. Evolution occurs as small changes that build up over time, exactly like a gradient.

And on that note, it's often sad to see creationists downplay these discoveries. Answers in Genesis, in response to the discovery of the apparent evolution of wall lizards and their cecal valves, claim that it is not evolution because no new genetic information had been added to the lizards, and that the sequel valves were were mere modifications of pre-existing structures and the lizards. However, this just shows how mistake in their view of evolution is. Evolution doesn't just grow new limbs or pop things in and out of existence. That simply just not how it works. It modifies pre-existing limbs and structures to look slightly different in proportions. Evolution is often just a mere modification of pre-existing structures, and over time, these small modifications build up. Over the general discoveries like these are so obvious and evident that creationists like Ken Ham and folks over at Answers in Genesis simply have to begrudgingly accept them and then claim that they only believe that the evolution goes to a certain extent. Only microevolution exists, they say. They claim that organisms can evolve within their kinds without really defining what a kind is. It's not a scientific classification, and without proving that such a process shows any signs of stopping or being limited to a certain point. In reality, there is no difference between micro and macro-evolution. The only variable is time. The distinction held up by creationist is just another attempt of shifting the goal posts to forever deny what is clear as day to people who actually want to see what the evidence has to say. It is by the exact same process that organisms can become slightly different from one another that organ is become largely different from one another. These discoveries showed that life on this planet is constantly changing, even just two short periods of time, in response to some of the smallest and my new pressures. Biology is a truly malleable and diverse thing, and it will be fascinating what changes occur in organisms in the distant future.

I hope you enjoyed this detour into what I thought were some interesting stories and hopefully have been able to help convince some people that evolution is something that exists in the world world and can be tested and experimented to be true. Well, anyways, thanks for watching, and I hope to see you next time, which I'm thinking might be a cryptid video or something, maybe Bermuda Triangle, because I haven't made one of those in a while. Alright, see you guys, and thank you so much for your time. I hope you enjoyed, and more importantly, learned something new.