The Weird Rules of Evolution.

If you have an extensive criminal record, such as myself, you've probably come to not like laws. They're just not hip, man. All they do is hold us down and refuse to let us act on our natural and unalienable rights, like mug-angled ladies. So I ask this simple question. Why can't we be like animals? Lawless, peaceful, part of the natural world. Well, unfortunately, even in the There are laws. Maybe not ones you can get tried and imprisoned for, but instead, biological rules. Now, although they are called rules, they are really more accurately described as trends. These are more like patterns we find in organisms rather than any set rules. These patterns aren't even set in stone anyways. There are countless exceptions to many of them, and some of these rules are dubious enough where they might not even apply as originally intended. Oh, and in case you wonder what's the deal with the names, most of these rules are usually just named after the scientists who thought them up instead of something interesting. For as we know, scientists are just the worst at naming things. If need be, I'll provide examples for any of the rules. And without further ado, let's get this list started. Gauss's Law, also known as Competitive Exclusion Principle, states that two species competing for the same resources cannot coexist with stable populations. It either leads to extinction of the lesser competitor, or a shift towards an ecological niche. If Bird Species A finds new competition for eating insects with the larger Bird Species B, then eventually Bird B will just eat up all the insects, and bully Bird A out of their own food. Bird A either faces starvation and dying out, or they adapt to eating seeds instead. Allen's Rule, animals who live in warm climates will try to maximize surface area to dissipate more heat, while animals in cold climates do the exact opposite. For instance, compare the African Elephant's big flat ears to the Woolly Mammoth's small ears. Bergman's Rule, in a widely distributed clade of animals, the largest sized members are found in cold environments. Examples of this can be found in penguins, bears, and even us, as ethnicities who live near the poles like Inuits tend to be heavier than other humans. The reason appears to relate back to Allen's Rule, a larger body gives you a lower surface area compared to your volume, which helps radiate less heat. Wrench's Rule, deals with sexual size dimorphism, which is where the male and female of the same species are different sizes. The size contrast increases with increasing body size if the male is the larger sex, and decreases with increasing body size if the female is the larger sex. This can be seen in the giant male elephant seal, who completely outbulks its female counterpart, to the point where they sometimes crush them while fighting for mates. Good job guys. Deep Sea Gigantism, this one easily takes the gold home for the best named pattern. As it says on the box, the deeper you go in the ocean, the larger the animals get in comparison to their shallow water counterparts. This once more might be due to Bergman's Rule, as deeper water also means colder waters. It can also be explained by the fact larger creatures can store more food away in the food scarce abyss, lack of predators, and increased oxygen levels. Unfortunately, this rule is hard to study since the ocean abyss is a difficult place to even access, let alone research. Famous examples include giant isopods, giant squid, and the Japanese spider crab. Dolo's Law of Irreversibility, an organism can never return or re-evolve back into its previous state, even if its living conditions are identical to those it formerly lived in. I can't really think of any good examples since this one sort of relies on a lack of examples, but just remember once you fold a piece of paper, you can never get rid of that crease. Foster's Rule, maybe better known as the Island Rule, states organisms will either get larger or smaller when placed on an island habitat. Animals which start out small tend to get larger with reduced predation, a phenomenon known as insular gigantism. Meanwhile, animals who start off large shrink due to the lack of resources on small islands, which is known as insular dwarfism. Two great examples of this are the giant 2 meter long swan and the dwarf elephant, who had a shoulder height of 80 centimeters, who both coexisted on the Mediterranean islands of Malta and Sicily. Cope's Rule, lineages of animals tend to increase in body size as they evolve. Named after Edward Drinker Cope, a man we've talked about before, this trend seems to occur because simply put, natural selection prefers larger animals to smaller ones, as they have a better shot at fighting off predators and competitors, killing prey, and surviving times of famine. But at the same time a larger body size means more energy required to live, as well as longer gestation times means larger animals aren't fast evolvers, and thus will eventually face extinction before they can grow any bigger. It also has been stated that instead of a constantly increasing size, animals may just reach a size cap where they can't grow any larger without meeting barriers in their physiology. For instance, giraffes would need comically big hearts to grow any taller. This trend is a bit dubious and not at all universal, but can certainly be seen in groups such as the dinosaurs, ancient marine invertebrates, and mammals. Harrison's Rule, a parasite's size is connected to the size of the host. This explains things like, and here's your fun fact for the day, the 30 meter tapeworms inside the bodies of whales. Williston's Law, as an organism evolves, certain body parts usually decrease in their amount, but become much more specialized in their function. Think of how our ancestors have many of the same teeth, meanwhile modern mammals have only a handful of very specialized teeth, like canines and molars. And finally, von Baer's Laws. Embryos develop from a common form into the more derived and specialized form of the animal, following the branches of evolution along the way. This means you can track a species' taxonomy through its embryonic growth, with closer relatives like humans and chimps sharing more derived traits in the embryos, while our more primitive fish ancestors may only share the most basic characteristics when comparing their embryos. So those are some of the rules. Just goes to show that along with things like math and physics, biology can show patterns we can use to predict the evolution of the many species on Earth. So there's this month's video. Certainly a more different one from the usual. I don't plan to make another one like this ever again. I thought the concept was interesting enough to justify doing a simple list for this, but, you know. Anyways, as always, thanks for the photos and videos I used, and of course, thank you for watching. Oh, and uh, see ya.