Thursday, February 25, 2016

Analogy & Homology

Homologous Trait

The two species that I selected for my homologous trait are dolphins and humans. Although these two seem to appear different and live in completely different settings, they both share a similar homologous trait and a common ancestor. Humans and dolphins both share the same bone structure including the formation in their extended limbs. Although one would not even consider a dolphin's flipper and human's arm to have any similarities, with further examination, one is able to see the similarity homologous traits. The similar traits that exist in the limbs of a human and dolphin include the carpals, phalanges, ulna, radius and the humerus bone fragments. Anyone can distinguish the fact that their is a difference in size and also the shape between the two. The reason for that is that they both live in different environments and use the functions of each of their limbs in different ways and different methods. Dolphins use their flippers for steering through the water and making sharp turns. In order to turn fast they use their back flipper because that helps push them forward. Their use of flippers is also used as communication be being able to touch and feel other dolphins. Humans on the other hand, also use their hands for many different tasks, (which everyone knows how). We use our hands and arms to eat, drive, write, drive and many other common tasks.  Their common ancestor will be a mammal, the reason for this is that all mammals share similarities in limb structures.

Analogous Trait

Humans and octopus are two species who both share a similar analogous trait. Humans and octopuses have similar traits but do not have them because of a common ancestor. Believe it or not, the trait between these two is their eyes. The human eye is very similar in structure to the eye of an octopus. An octopus eye is very similar to the eyes of vertebrates. The unique part is that they have been shown to have evolved independently. Both eyes have evolved lenses and also very similar structures. The difference though is that the eyes of octopuses is superior to the human eye in that they do not have blind spots. This is the only real difference between the eyes. The both have lenses to refract light, a pupil to restrict incoming light, following a retinal surface that is distributed along the back of the eye. These two do not carry the same trait because of a common ancestor. Scientists are still trying to figure out deeper information on octopuses besides knowing that they are one of the mysterious creatures in the seas. Scientists and researchers believe that they are "aliens." Although it might sound crazy, their findings lead them to believe that, even as a joke. Octopuses have 33,000 genes which is roughly 10,000 more than a human. That alone, we can come to the conclusion that they do not have a similar ancestor so they are not homologous to humans.

Thursday, February 18, 2016

Thursday, February 11, 2016

Historical Influences

1. I believe that it can be argued that French naturalist, Jean-Baptiste Lamark, had the most influence over Darwin's development of his theory of Natural selection.

2. Lamark contributed to the scientific community in numerous ways but began by being one of the first to propose that humans evolved from a lower species through adaptions over time. Although his primary theory was was proved wrong, he continued making observations and with his explanations he combined, this lead to having a new process of thinking which has made an impact of Darwin and had him inspired. Jean-Baptiste's evolution theory started out as very simple however it eventually built up until it was created into a complex human form. He believed that if an organism changed during life it's life in order to adapt to its environment, those changes will then be passed on to its offspring. His thought on change was that it is made by what the organisms want or need. Another theory of his was that the body parts that are not being used will gradually be disappearing. Lamarck's additional beliefs of evolution was that it happens based on a plan which leads to having the results already been decided.

3. The concept that was most affected by Lamark's work was the evolutionary concept if the environment changes, the traits that are helpful or adaptive to that environment will be different. Despite being proved wrong, his hypotheses and observations is what began the study of different species and their ability to adapt to the environment. This lead to discovering the new adaptive traits that will have a higher reproductive success than others, not only that, but the new traits will spread which will have an impact in the population. This is the process of natural selection; the natural environment selecting the organisms that will be the most successful.

4. Although many of Darwin's theories have been supported by a numerous amount of evidence, it is possible that Darwin may have developed his theory of natural selection without the work of Lamarck. I'm sure there are many others who have the same idea or thoughts but don't have a sufficient evidence to support their theories. Anyone can be influenced by anyone's work, even if their ideas have not been proven. As for Lamarck, despite being proved wrong, his ideas and thoughts could have been an influence on Darwin. Darwin and Lamark both thought that life had changed gradually over time and was still changing and that living things change in order to adapt to their environments. They both could have approached their ideas differently and receive different results, but it is possible that they may have been influenced by each other or even others.

5. The attitude of the church affected Darwin and his publication. Darwin was not only questioned but he was also criticized when he came out with his publication "On the Origin of Species." His theories and ideas of evolution was received as a disrespect because he was going against the belief of the church's belief of God's work or creation. This is the reason why Darwin kept holding his publication back because he was aware of what might occur when others saw his work. What he predicted came true but Darwin also received a lot of praise for his work.