Scientific theory is an observed and tested phenomenon, governed by a set of well-supported rules, facts, and explanations. However, this differs from how we normally think about a theory because a theory is basically formed by a hypothesis that attempts to connect facts together based on speculation. However, a hypothesis is an observable, proposed idea or explanation. In the case of the law of Parsimony, Occam's Razor states that “entities should not be multiplied beyond necessity,” so in science we should not make assumptions about things that are in excess of necessity. In the case of multiple hypotheses, the law of parsimony is a general guideline applied, it suggests looking for the simplest and clearest hypothesis, with empirical evidential support first, in order to remove unnecessary hypotheses. Parsimony is used more specifically in taxonomy to produce the fewest groups in phylogenetic trees, to avoid excessive grouping. Scientists must communicate their latest findings and inform colleagues and the public about new data. They can present these findings at conferences where a group of their peers can listen to the presentations, at universities, or through popular journals and media. The main outlet that scientists use to communicate their findings is by publishing them in journals, which are archived, so that they can be read and referenced in the future. Some journals go through something called peer review, this is when your paper is published after other scientists have reviewed it and deem it to be of good standard and quality. This strengthens the scientist's reputation and offers a large audience, making it easier for other scientists in their field to be easily accessible and reference their findings while doing similar research, such as research into descent from common ancestors. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay It is known that every species living today is the result of the evolution of pre-existing species throughout their lineage, if you follow the ancestors of two modern species at some point they will intersect with the two lineages on the tree genealogical of life, indicative of a common ancestor, so all organisms today are all descendants of species that no longer exist and the closer the species is they come from their common descendant the more related they are. When the whole idea of ​​common descent was proposed, Darwin had no understanding of genetics, but today we see that when scientists compare the genomes of different species they find similarities in the number of chromosomes and their location, with fossil evidence they have also been in able to find similarities between bone structure of different species and their assemblages. A typical example of descent from a common ancestor is the evolution of the horse, no evolution of other species is as well documented as the horse lineage, this is due to the abundance of fossils found throughout North America from over 50 million years ago, this allows us to reconstruct a large part of the horse's family tree. The rise of the horse epitomizes the phrase "survival of the fittest", as along this lineage there were some branches that had perished, the story of the horse's evolution is a story of constant adaptation and radiation in response to Northern climate changes America. The Hyracotherium (Eohippus) was the first equine animal to grow about 55 million years ago, it was as large as a fox, hind legs longer than the front ones with toes each covered by separate hooves (four on the front limbs and three on the hind limbs ). , teethomnivores, with its 20 million years of existence, its first complete fossil was found in 1876, this forest creature has arrived to equids. As the equid family diversified, there were more than a dozen genera populating the Northern Hemisphere, as opposed to the single genus that remains today, the eques (modern horses, donkeys, and zebras). In the Eocene the climate was dry, giving way to a mosaic of arid grasslands, in this environment it is believed that the descendant of the eohippus, the mesohippus, appeared for the first time, which quickly diversified into another genus, the miohippus. These two roamed the earth at the time, but they were both different from the eohippus as they were beginning to adapt to the changes that had occurred in the landscape of North America. Their preserved teeth show that they had more molars and a higher ridge to aid in grinding fibrous foods such as grass, unlike eohippus. The fossil bodies also indicated that they were starting to have much longer legs, which may have helped them take faster steps. The front fourth toe had also disappeared as had the middle finger, it is believed that this was necessary to support the mass. greater than they had. now he had. In the Middle Oligocene the smaller mesohippus disappeared leaving the larger myohippus, which subsequently radiated into many different species in the Miocene epoch. This time there was a lot of swampy area, the parahippus, descendant of the paleontologist myohippus, was able to meet one of their species, it is said to be the first horse to be a hypsodont, which gave it a greater advantage to live in the plains, when it came to eating tooth-wearing grass. From the lineage of the perahippus the fossil finds show that a new genus had evolved, called merychippus (the first true equine), it was much larger, the long head similar to that of a horse, its legs were particularly adapted to running on land hard, all of his weight was supported on 3 toes by elastic ligaments, his front legs were much longer and stronger thanks to the bones fused together. Several Merychippus descendants later became monodactyl, as this would have reduced the stress caused by their weight gain. Then there was the Pliocene epoch, where one of the single-toed equines finally gave rise to Equus (genus of the modern horse), the oldest species found being Equus simplicidens, it was about the size of a modern horse, teeth similar, fully fused leg bones for better protection and locomotion, long face and neck for better feeding, and standing mechanism developed an adaptation for standing for long periods. They subsequently crossed different continents, during this period all three-toed horses became extinct as well as most monodactyls. At the end of the Pleistocene most of the large mammals including Equus became extinct in North America, it is believed that hunting by early humans, competition for food by other larger animals and climate change due at the end of the last ice age. However, the migrated horses managed to survive on other continents that supported their favorable environments, which were able to repopulate North America. In 2013, a group of researchers managed to obtain the DNA sequence of a horse's leg bone buried in permafrost that dates back approximately 560-780,000 years. old. They compared the sequence with that of a 43,000-year-old. an old Pleistocene horse, a Przewalksis horse and together with 5 modern horses and a donkey, when the differences between the genomes were analyzed, they found that the last common ancestor of them existed for 4 to 4.5 million years. ago. The whole idea of ​​survival,.