Charles Darwin Domestication Essay

One day in 1855, Charles Darwin went for a walk in London. He saw some pigeons and wondered if they had a common ancestor as fancier pigeons. He observed them and concluded that both species descended from the rock dove. He believed that since man could breed several forms from a single thing, nature could too. Domestication became a laboratory for Darwin to study evolution. Charles Darwin noticed that in mammals, virtually all domesticated species shared some characteristics that their ancestors didn’t have. Darwin thought these characteristics would have something to do with the hybridism of different breeds or the living conditions of tamer animals, but he couldn’t explain how such a process could produce such a broad spectrum of features
across the many different species of animals. Domestication in animals has been pondered for centuries.
Advances in animal genetics has brought to light some of the mechanisms used to domesticate animals. They are deeply tied to the Neolithic
revolution. Domestication has multiple ways of being done. Studies have shown that several species have gone from being domesticated to not being domesticated several times throughout their history. As time went on, it became clear that the changing of animal genetics by humans has resulted in animals changing humans. Melinda Zeder, an archaeologist at the Smithsonian Institute, has identified three main paths to domestication. The ‘directed’ path is the most straightforward. This happens when humans set out to change certain traits of an animal. The ‘prey’ path is taking animals that humans used to hunt and raising them in herds. The ‘commensal’ path is animals becoming attracted to humans due to attractive food sources. Cats became domesticated in this way. Dogs became domesticated between 14,000 and 32,000 years ago. They came from wolves. Because they were domesticated so long ago, finding their location of domestication has been proven to be a daunting task. By using the DNA of dogs from burial sites, researchers have tracked the location to somewhere in East Asia, Central Asia, the Middle East or Europe. According to a study done in 2016, certain DNA from dogs suggests that there were two instances of domestication: one in Europe and one in Asia. Studies of pig genomes have shown that the domestication of pigs happened on at least two separate occasions. Early European farmers arrived with swines and the swines bred with boars to make modern domesticated pigs. Overall, domestication was a gradual affair. In 1959, the Russian biologist Dmitry Belyaev moved to Siberia to make an attempt at speeding up the evolution of dogs. He took 100 female foxes and 30 males foxes. After 6 generations, foxes started to act like puppies. They also started to look more like modern dogs. This experiment has been running for nearly 60 years. All the foxes there show signs of domestication syndrome, which means they are all different from their ancestors. All of this came about simply because foxes were selected to breed based on their level of tameness, which was based on how scared or aggressive they were towards humans. These results suggest that domestication is caused by a gene or a set of genes that occur naturally, but tend to be selected when species adapt to things. One recent hypothesis suggests that neural crest cells, which are cells that form early in the embryo and form many important tissues in the body, may play a part in the domestication of animals. If any of the cells change at all it could result in animals being born domestic. Domestication in animals doesn’t come without consequences. The brains of domesticated animals are smaller than their wild counterparts. However, it is unclear whether the shrinkage of the brain corresponds with intelligence.
The areas that are smaller are the parts that give an advantages to wild animals, such as the part that enhances sight, hearing, or smell. The process of domestication is hard to reverse. Dingos have been wild for over 3000 years, but they still have the small brains that their domesticated ancestors had. Domestication of animals has not only changed the way many species live today, but it has also changed the way humans live. It used to be that humans couldn’t digest lactose. They gained the ability once they started to domesticate animals that produced milk. This is because they started to get a steady supply of it and their bodies adapted to digesting a certain enzyme in milk. Humans could drink milk before that, but research shows that it was probably uncomfortable. With the introduction of domesticated farm animals, and with that came agriculture. Agriculture exposed humans to a plethora of different pathogens. Clearing land for crops created standing pools of water, which became breeding grounds for the deadly diseases that mosquitoes carried. Blood irregularities found in humans are thought to have been a result of
this.