In the 10th year after the publication of On the Origin of Species, Darwin lamented: "If I have 20 years left, how many views still need to be revised?" It is only part of the truth. "Over the next century or so, there were a variety of discoveries, 99% of which Darwin did not know about. On the occasion of the 200th anniversary of Darwin's birth, Nature magazine has selected 14 "gems" in the history of biological evolution, which are distributed in all corners of the earth, showing us the magical power of evolution and validating the theory of evolution.
<h1>Terrestrial ancestors of whales</h1>
Scientists once found a 500 million-year-old fossil called "Indojos". Indochos is about the size of a dog, has ears and teeth, and has a iliac structure similar to that of a whale, feeding mainly on terrestrial plants. In addition, its limb bones are thick and heavy, similar to hippopotamus, which suggests that it belongs to the wading animals, because the heavy bones prevent floating. After analysis, scientists believe that this is a land mammal, the terrestrial ancestor of whales. Whales may have evolved from this animal about 50 million years ago, and the main reason they entered the water was to avoid predators, and it was much later that they developed special underwater predation habits.
<h1>"A walking fish"</h1>
A few years ago, scientists discovered an ancient new species called "TikTalik" on Ellesmere Island in the northern part of the Gajue. This animal lived about 375 million years ago and is known as a "walking fish". It has a flexible neck and limb-like fins, gills and lungs, which are traits that favor it in shallow water. Unlike primitive fish, it has sharp teeth and a flat head like a crocodile and may have adapted to shallow water life, though sometimes leaving the water and climbing onto land. Scientists believe that Tiktalik is the ancestor of all terrestrial vertebrates, including amphibians, reptiles, mammals, and humans.
<h1>Natural selection in flight</h1>
More than 10 years ago, scientists put a large carnivorous lizard, the northern capuchin lizard, into six small islands in the Bahamas, and then they found that a "game" began between the lizard and its favorite prey, the Shah's color-changing lizard. If the northern capuchin lizard encounters a male Sands chameleon, the latter's legs become longer in order to escape more quickly; if it encounters a female Sands Chameleon, the latter will choose to stand still and become larger, making predators think it is a food that is difficult to swallow. This escape strategy illustrates that one organism can influence the evolutionary behavior of another and has sex differences.
<h1>The origin of the bones</h1>
Fossils alone do not study certain cells that appear only briefly during the embryonic period, such as neural crest cells. Later techniques by labeling and tracking neural crest cells found that they produced bone lock cells on the face and neck by migration, as well as specific cells in the skin and sensory organs. Since neural crest cells are specific to vertebrates, this explains why vertebrates have a particular face and neck. In this way, the evolution of the head and neck structures of long-extinct animals can be described in detail without fossils. For example, from the localization of the shoulder blades of most extinct land vertebrates, the key bones of fish (the ring-shaped bones on the body of fish) correspond to the shoulder blades of mammals.
<h1>A protracted "arms race"</h1>
Scientists have studied water fleas and parasitic mites living in the muddy environment at the bottom of the lake, and found that water fleas and parasitic mites have always been engaged in an "arms race": whenever water fleas have a more convenient way to escape parasitic mites, parasitic mites will evolve corresponding countermeasures to continue parasitizing on water fleas. This shows that any evolution of one species may constitute competitive pressure on other species, thus promoting species evolution.
<h1>"Feathered dinosaurs"</h1>
In the 1980s, scientists unearthed "feathered dinosaurs" that lived about 125 million years ago, but their feathers were more about warm or beautiful than flying. In 2008, Chinese scientists discovered a dinosaur that was closely related to birds, the "Hu's Yaolong". Unlike other known dinosaurs, this dinosaur had teeth on its upper and lower jaws and had teeth tilted forward, and the size of these teeth also differentiated, forming a bite platform structure similar to the canine or incisors of some mammals. These findings not only prove the existence of transitional organisms, but also that flying may be an additional sporadic event after the animal has grown feathers.
<h1>Evolution of teeth</h1>
One of the purposes of studying development is to discover the mechanisms that guide evolution. Through the study of gene expression that controls the development of mouse teeth, scientists have discovered mechanisms that control the size and number of molars in mice. Rodents are omnivores, similar to human teeth, and their molars are also toothless in order from front to back, and each tooth is smaller than the front. This study suggests that ecology can also act as a separate force to advance evolution, allowing some of the properties of organisms to be constantly modified in evolution to adapt to changes in the environment.
<h1>The impact of geographical differences</h1>
Scientists have found that the genetic variation of the chicks of the giant that inhabit different trees varies, and that different habits also strengthen the adaptability of the giant to some extent. Another study found that the migration of large is not random, and there are a large number of genetic differences in each litter, which once again illustrates the evolutionary impact of migration.
<h1>Macro evolution</h1>
Darwin believed that evolution was a slow change in small steps. In 2005, scientists discovered a molecule whose small changes directly affect whether spots appear on the wings of male fruit flies. In this way, genes can also control significant changes in appearance, thereby driving macroscopic changes.
<h1>The genetics of the choice</h1>
Scientists have found that male peacocks with bright feathers are more attractive to the opposite sex than their mundane companions, giving birth to offspring, resulting in higher survival rates. This suggests that the natural evolution of species favors those that are rare and varied rather than ordinary. Scientists believe that some immutable genes may seem useful in the short term, but could spell disaster for the species in the future.
<h1>Sudden variation</h1>
Changes in species do not necessarily require millions of years of accumulation, and sometimes occur suddenly. Early studies of Fruit flies found that there is a protein that is usually produced only when the body is under stress. Back in 2014, scientists discovered that most genes have the potential to mutate and are only released when their function is impaired.
<h1>Evolved ideas</h1>
Unlike other fish, moray eels are slender and theoretically unable to generate enough suction to catch prey. In 2017, scientists found that moray loach had evolved to find a solution: "moving" the pharynx to the front of the mouth, so that it did not take much effort to suck in the prey, but also blocked the prey's retreat. This is the first time a vertebrate has been found using a second set of throats to limit the activity of prey and swallow it into the stomach.
<h1>Reproductive isolation</h1>
In 2004, scientists studied the three-spined fish in alaska and other regions, and found that when the fish migrated from the ocean to the stream, they continued to adapt to new environments and underwent many subtle changes in their shape. Now, even if they are allowed to re-mix together, they tend to look for similarly shaped counterparts in the choice of mates. In this way, the three-spined fish has evolved reproductive isolation. This study powerfully links reproductive isolation to the discrete features of ecology.
<h1>Darwin Tits</h1>
As early as Darwin's expedition to the Galapagos Islands, he found that the difference in the shape of the mouths of on different islands corresponded to their eating habits. In 2006, scientists also found that the difference in the shape of the tit's mouth is determined by the difference in gene expression of a protein. In experiments, when gene expression of this protein was artificially increased, the mouth of the embryo became more pointed.
<h1>Shortcuts to evolution</h1>
Humanity's mastery of genetic modification and stem cell modification makes it seem that we can bypass natural selection and enter the explosion process of actively controlling biological reproduction and evolution. Here are the latest and greatest discoveries in gene biology.
In 2015, scientists converted adult skin cells into stem cells, which in turn transformed stem cells into other desired cell types. This major scientific advance has caused a stir in the entire scientific community – perhaps in less than 5 years, we will be able to experimentally engineer any somatic cell into sperm or egg cells, thus bringing good news to infertile couples, perhaps they can just provide some skin cells to pass on their genes to their children.
It has even begun to be conceived that after creating the desired egg cells and sperm, it is also possible to remove some of the unwanted genetic information and replace it with useful genetic information through a technique called "homologous recombination". Genetic recombination was originally a natural occurrence in sexual reproduction, but now scientists in the lab have been able to add or knock out some dna fragments in the eggs of experimental mice. Perhaps in the near future, we will be able to knock out some potentially pathogenic genes (such as diabetes) or artificially add genes that will help you get taller or smarter. Changing the DNA of future generations one by one is a tedious task, and we might be able to insert an entirely new chromosome to transform the DNA once and for all. Some scientists believe that synthetic chromosomes are like "Trojan horses" put into the body, they can turn ordinary cells into wonderful stem cells, can replant the immune system, and can also rejuvenate people. Since nature doesn't care whether a particular child is good or not, instead of waiting for God to roll the dice, we should put it ourselves directly on the side we need most.
If we do control our genes, maybe one day in the future we can turn ourselves into a new species (compared to other creatures, human genes are really nothing special). However, ethicists believe that changing human genes requires caution, and what the consequences of artificially accelerating evolution are not yet available.