In Footnote #106, Kate Berg
elaborates on the origin of the modern day human, which dates back 200,000
years to Africa (304). She also lists characteristics of an “anatomically
modern” human, deeming that he/she should possess “a high rounded skull, facial
retraction, and a light and gracile…skeleton” (305).
Why do you suppose natural selection
has favored these or other specific traits of humans? Discuss the reasons behind
why natural selection has favored three specific traits (3 minimum). You may
want to consider traits such as bipedalism, imposable thumbs, etc. Also, will
humans continue to evolve drastically, or have we reached a relative “perfection”
so much so that evolutionary changes that follow will be slight? Are the forces
of natural selection acting on humans the same as they were hundreds of
thousands of years ago? If not, how have they changed?
-Diane Kuai
(dianekuai@gmail.com)
This comment has been removed by the author.
ReplyDeleteNatural Selection is process that favors traits based on the environment an organism has to adapt to in order to produce offspring. An anatomically modern human has a very large brain, imposable thumbs, and a more graceful frame. These features were selected because they fit the environment that a modern human today has to live in. In the past, Homo sapiens “gathered and hunted food, and evolved behaviors that helped them respond to the challenges of survival in unstable environments” (http://humanorigins.si.edu/evidence/human-fossils/species/homo-sapiens). Homo sapiens had a broader body shape capable of handling more damage than humans today. The reason for this was because Homo sapiens had a much more physically demanding life than today. Now, people have a more graceful body because technology has made it possible for us to avoid the physically demanding life. However, in order to create this type of technology and advancements that make life easier, we have to be able to use our brain and hands. A larger brain enables us to know and learn more information and think of new innovations. These innovations are created by our hands which now have imposable thumbs. In essence, natural selection favored these traits because they were fit for the environment in which humans live in today.
ReplyDeleteAccording to Jon Entine, “among the small population of elite athletes, there are differences that could give a fraction-of-a-second advantage to people of African ancestry” (Shenk 307). Entine is suggesting that the genetic makeup of someone with African ancestry is more physically fit than the average person. This means that Homo sapiens did indeed derive from Africa and their closest ancestors today develop some of the same genes they had. This makes sense, because in most sports today, such as basketball, many people of African descent are exceptional at sports and have the physical build in order to make it their career. Although the human appearance hasn’t changed much in the past couple thousands of years, our body and shape will never be perfect. The environment around us is constantly changing, and in order to adapt to that, our body needs to keep changing. There are many new diseases being discovered, and the effect of global warming is escalating. If the human race still exists a million years from now, our makeup will have indeed evolved in order to fit its surroundings.
Charles Darwin was the one who discovered the concept of evolution which “occurs as the unequal reproductive success of [how] individuals [adapt] the population to its environment” (Campbell 16). Evolution is the reason that there’s so much genetic diversity today. Every generation, organisms are changing their genetic appearance in order to fit the environment in which they live. Therefore, the environment is ultimately determining what genes are going to be changed or left unchanged.
(Anisha Ghosh anishaghosh16@gmail.com)
Natural Selection favored those specific traits of human because they help us reproduce and survive better. Having high rounded skull helped anatomically modern humans to protect their enlarged brain. Enlarged brain is what makes human different from other animals, so protecting them helped them to survive better. Light and gracile skeletons had lots of advantages on modern humans. Africa have limited supply of food and water, by having light skeleton, it helped modern humans to save energy. Also, having light skeleton made humans to run fast when they were in danger. Even though these skeletons were light and gracile, they were strong. It protected our internal organs very well. Other traits like bipedalism made us able to use our hand while walking or running, having opposable thumbs helped modern humans to get better grasp on stuff than other animals. These traits that natural selection favored helped modern humans to survive.
ReplyDeleteThe human evolution might have been slowing down on our environment because of all the modern technology. Things like vaccine helps us to fight of bacteria without making us go through evolution and making us immune to them. But it doesn’t mean evolution completely stopped. In the modern world, we can still see evolutionary changes in modern human. For example, in Africa, malaria causes thousands of people to die each year. Because of malaria, sickle cell anemia is especially common in Africa. Sickle cell anemia helps those people to become immune to malaria, so natural selection favored that trait in that environment.
http://humanorigins.si.edu/evidence/human-fossils/species/homo-sapiens
Campbell Textbook, pg 502
(skt07071994@hotmail.com)