Analogy/Homology

Dolphin Flipper vs. Human Arm/ Hand

a. Two different species that posses the homologous trait are dolphins and humans. The dolphin flipper and the human arm/hand have similar structures.

b. The dolphin flippers act as stabilisers and are used for steering, while swimming, and can act as brakes, along with the tail. They are made of collagen- rich connective tissue, that are very similar to the bones inside a humans arm and hand. The joint that is comparable to the elbow is located at the body surface. The humerus has a large- globular head where it meets the scapula in the shoulder joint. Arteries in the flipers are surrounded by veins. So, some heat from the blood traveling through the arteries is transferred to the venous blood. This countercurrent heat exchange aids dolphins in conserving body heat. To shed excess body heat, circulation increases in veins near the surface of the flippers and decreases in veins returning to the body core.

The humerus articulates with the scapula at the shoulder and with the radius and ulna at the elbow. It is a long bone that is essential for movement and support of the arm. The brachial artery travels most of the bones length. The brachial artery branches into several arteries, distributing oxygenated blood from the lungs and heart. The hand exhibits great mobility and flexibility in the digits and in the whole organ. The complex abilities of the hand are part of what makes humans unique. The hand gives us a forceful grip and we use our hands the most out of anything else on our body.  The structures are different between dolphins and humans because the human’s arms are much longer than a dolphin’s flipper. Also, humans a more vertical and dolphins swim more horizontal.

c. The common ancestor of dolphins are Pakicetus. We know this because its legs are shorter, and its hands and feet are enlarged like paddles. Its tail is longer and more muscular, too. The ear region of the skull resembles fossil and modern whales, and the teeth and other features are similar to those of some fossil whales. Whales and dolphins come from the same common ancestor. The common ancestor of humans is the Chimpanzee. Shoulder shape tracks changes in early human behavior such as reduced climbing and increased tool use. Chimpanzees are the closest living relatives to humans.

d.               

Bird Wing vs. Bat Wing

a. Two different species that posses the analogous trait are birds and bats. I chose the wings on a bird versus the wings on a bat.

b. Bird and bat wings are analogous because they have separate evolutionary origins, but are superficially similar because they evolved to serve the same function. Bird wings and bat wings are analogous as flight structures: their structure and function have evolved by different routes from a flightless reptilian ancestor. A good portion of the flight surface in bats consists of a membrane stretched between the extended digits in the hand, whereas the digits of the bird are relatively small and do not support the flight surface. Birds have the same arm bones as humans and bats, but the bones are arranged in their wings very differently than the bones in bat wings. Bird and bat bones look small and delicate. This was thought to make both bird and bat bones lighter so they can fly.

c. The discovery that birds evolved from small carnivorous dinosaurs of the Late Jurassic.  The common ancestor of bats Laurasiatheria; which is a superorder of placental mammals. Because Laurasiatheria is defined by DNA sequence analysis, the group does not share any obvious anatomical features. So, this branches into categories. Bats are mammals in the order Chiroptera. They are the only mammals that can fly. In these categories also include carnivores. Bats and birds are not genetically related because the structure in their wings and the way they fly are fairly different. Birds have more gaps and feathers in their wings to help them glide through the air whereas bat wings don’t, so it seems as they are swimming through air.

d.         

DNA

GCCATACCAAGGGAACGTAAGTGTCACGGGCUUGAUC

Charles Darwin and Alfred Russel Wallace

Nicole Joseph

Professor Rodriguez

Anthropology 101

February 11, 2016

Charles Darwin and Alfred Russel Wallace

1. In my opinion, Alfred Russel Wallace had the most positive affect over Darwin’s development of his theory of Natural selection.

2. Alfred Russel Wallace is best known for his theory of evolution through natural selection. Wallace left on a voyage to the Dutch East Indies to observe wildlife and collect specimens, which took him eight years. Wallace finally came to the conclusion that living things evolve and wrote down his theory and sent that to Darwin. Even though Darwin had already come up with his own theory of natural selection, Wallace sending his theory motivated Darwin to finally act.

http://www.npr.org/2013/04/30/177781424/he-helped-discover-evolution-and-then-became-extinct

3. Darwin and Wallace believed in the same thing, natural selection. When both of them went on their voyages and did their research, they came up with significantly different theories to what they observed. From the bullet points, what they did not agree on was, if the environment changes, the traits that are helpful or adaptive to that environment will be different, In order for traits to evolve and change, they MUST be heritable, individuals do not evolve. Populations do. Additionally, I found that they both agreed that nature is a battle, with the heaviest casualties often occurring among the young. However, they did disagree on a few things. Darwin emphasised competition between individuals of the same species to survive and reproduce, whereas Wallace emphasised environmental pressures on varieties and species forcing them to become adapted to their local conditions. And Wallace had envisioned natural selection as a kind of feedback mechanism keeping species adapted to their environment. Wallace believed science was simply the search for truth in the natural world and Darwin believed that science must invoke only natural processes functioning unbroken natural laws in nonteleological ways.

4. I do not think Darwin would have been able to take his theory of natural selection to the length that he was able to take it without Wallace. Wallace had long worked on a theory of natural selection. When he did, he wrote down what he came up with and sent that to Darwin, who was also working on his own theory.  All we hear about today is Charles Darwin, we did not know who Alfred Wallace was because Darwin got all the credit. Also, there were times when Darwin wrote to Wallace asking questions that he did not understand about why animals do what they do. There were times when Wallace supplied Darwin with birds for him to conduct his experiment on, and Wallace was not mentioned.

5. Darwin knew he could get into trouble and ruin his career believing in his theory. What Darwin was concluding was unorthodox and not only went against the church, but because it went against all of the natural history in Great Britain. But Darwin knew what he believed and truly believed that his research should be out there for everyone to see. He published his book on November 24, 1859.

Island

If I were trapped on an island and could only bring two things, I would bring my dad and a knife.

I would choose to bring my dad because he is the most outdoors man I know. He loves to hunt and fish. Also, he knows how to adjust to changes because every time he goes on a hunting trip, the weather can change and he had to adjust to that. He knows how to carve anything with anything. He would be able to not only help me survive, but teach me what he knows.

Second, I would bring a knife because a knife can be used for anything, such as killing and carving. I need to eat, so I can use the knife to get food. Then, I can use the knife to carve or peal anything to help me eat and survive.

At least I won't be alone!