Homology/Analogy Blog Post

Darlene Jones

Anthro Blog Post week 3 Homolgous/Analogous Traits

1a) The two species chosen to express the homologus trait are humans and the aye-aye’s. Homologous traits are those that are from a common ancestor but use the trait in different ways. Fingers were the homologous trait that was chosen to compare these two species. Aye Aye’s are a part of a group of primates known as prosimians. They are related to chimpanzees, apes, and humans. They live in the tropical rainforest of the Madagascar. Humans are primates, and are related to the same species. Unlike the Aye Aye’s only being native to one location, humans live in variety of terrains and landscapes.

1b) Aye aye’s use its long middle digit to tap on the bark of the trees and listens for the movements of the larvae of wood-boring insects and grubs. If it does detect any sound, it cracks into the wood, biting through the exterior layers of the bark, and then using the same long middle finger to ferret the insect larvae out. This extra long finger is also used to scoop out the flesh from coconuts as well as other fruits which augment the aye-aye’s diet of insects. More than commonly humans use their fingers to use tools; Aye-Aye’s use their fingers as tools. Aye-Aye uses their fingers to hold onto when climbing since they live in a habitat requiring them to dwell in such environments. Humans use their fingers in a plethora of uses such as, nurturing, touch, and caress within social interactions. As mentioned above, humans fingers are also used for manipulation of tools such as; eating utensils. Aye-Aye haven’t evolved into using tools, they use their hands/fingers as such.

 The structure is different of the hands in both species. Aye-Aye’s have one very long slender finger and used mostly as a tool. Humans fingers are usually proportioned to their hand and not slender.. Aye-Aye’s middle finger, which is what they use the most to pull their food out of holes, is extended past all the other digits significantly. Human’s fingers usually have the middle finger longer but not noticeably longer than the other phalanges.

1c) The Lemurs are known generally as the immediate ancestor of the Aye- aye. Homo sapiens immediate ancestor would be the homo Rudolfensis. Since Aye Aye’s ancestry is closely related to Lemur’s we know that Lemurs use a similar style with their fingers for eating and climbing as the Aye Aye’s do. We also know that human ancestors used their fingers in a similar way as we do today.

1d)

Aye Aye uses their hands for grapsing

Aye Aye uses their hands as tools, notice the opposable thumbs.

Humans displaying touch with hands

2a) Two species chosen to express an analogous trait shared is the Sugar Glider (Petaurus breviceps) and the Flying Squirrel (scientifically known as Pteromyini or Petauristini).
The Sugar Glider is a marsupial that lives in Australia over a greater range of latitudes than any other Australian marsupial. It lives in northern, eastern, and south-eastern Australia. They are nocturnal, meaning they sleep in their nests during the day and are active at night. When legs are stretched out, this parachute like membrane allows it to glide distances of 50–150 meters. This gliding is regulated by changing the curvature of the membrane or moving the legs and tail.
The Gliding Squirrel lives in North America. This unusual creature is a placental mammal glider that has a squirrel-like body with a long partially prehensile tail.  They are not nocturnal. The Flying Squirrel has a parachute-like membrane that stretches from wrist to ankle. The recorded distance is 90 meters. It has a fluffy tail that stabilizes in flight.

2b) Similarities in structures and functions of the flying Squirrel and the Sugar Glider’s analogous traits are mainly focused on the membranous tissue that exists between both their abdominal areas. This membrane is an expansion of loose skin between their fore and hind limbs which allows them to glide. The “gliders” are both covered with fur. They both use their gliders to go from tree to tree or limb to limb; to relocate locations. When legs are stretched out, this membrane allows these two simular creatures to open up this tissue to allow this ability to take place. This gliding is regulated by changing the curvature of the membrane or moving the legs and tail. They use this to escape predators as well. This unique characteristic is native to both species of mammals.

2c) The common ancestors of the Sugar Glider are Kangaroos, wombats, and opossum. They did not have this analogous trait. None of these ancestors had ‘gliders’ or expansion of tissue for them to use in this way. The common ancestors of the Flying squirrel are rodents called Sciuridae such as the prarie dogs, chipmunks, and ground/tree squrriels.

2d)

Flying Squirel

Flying Squirel

Sugar Glider

                  Sugar Glider 

Protein Synthesis assignment

UUGCTACCAAGGGAACGGCAGCTGGTGTAAATCGATCCTT

Charles Darwin

1. Select one of the five individuals listed above who you would argue had the  most influence over Darwin’s development of his theory of Natural selection. This could be a positive or a negative influence. 

 I would choose French naturalist names Jean-Baptiste Lamarck had the most influence over Darwin's development of his theory of Natural Selection. I believe this was a positive influence in its own way. Unlike Darwin, Lamarck believed that species evolved through a specific process of choosing what traits worked best for the environment and constantly making these traits more complex. Darwin believed there was a selection in who survived, who receives traits. "This means they must be passed on reliably from generation to generation through reproduction. This was actually a problem for Darwin as he did not know how traits were passed on. The current thinking of that time argued for Fluid or Blending Inheritance".adaptive to that environment will be different. Organisms with those new adaptive traits will have greater reproductive success than others and those new beneficial traits will spread, producing a change in the population. This is the process of natural selection, essentially the process of the natural environment selecting the organisms that will be most successful". 
2. Briefly (but completely) describe the contribution this individual made to the scientific community.

 Lamarck suggested a relationship between species and the environment. He suggested that when the environment changed, animals activity patterns also would change to adapt. According to Lamarck, organisms altered their behavior in response to environmental change. Their changed behavior, in turn, modified their organs, and their offspring inherited those "improved" structures. His theory is known as the inheritance of acquired characteristics, or the use -disuse theory. This would result in the increase or decrease (the use or disuse) of certain body parts. In other words, as the environment changed, the animal would have body parts that would change to accommodate the new surroundings. If this meant longer necks or shorter legs or thumbs, sharper teeth, etc; then this is what would happen. Lamarck emphasized the importance of interaction between organisms and the environment with the process of evolution. He is not correct  on his explanation of species change genetically; but his idea is correct. Lamarck is credited with helping put evolution on the map and with acknowledging that the environment plays a role in shaping the species that live in it.
 Work Cites:
http://www.pbs.org/wgbh/evolution/library/02/3/l_023_01.html
www.victorianweb.org/science/lamarck1.html

3. From the bullet point list above (under "How does evolution work?"), identify the point (or points) most directly affected by this individual’s work and thoroughly explain how this point was influenced by your selected individual. Again, this could be a positive effect, meaning Darwin built upon the knowledge this information provided, or a negative effect, meaning that Darwin demonstrated that this individual’s idea(s) were incorrect and the mechanism of natural selection was an alternative explanation. (10 pts)

"If the environment changes, the traits that are helpful or
~ This involves the concept of Lamarcks idea that animals wll change and adapt to their new surroundings for survival....to continue. The traits that are most desired in maintaining life and continuing will be created and passed on.

"In order for traits to evolve and change, they MUST be heritable.
~Traits must be inheritated in order for then to evolve and adapt to the new environment. This correlates with Lamarcks idea "inheritance of acquired characteristics".

"Individuals do not evolve. Populations do. Individuals cannot change their heritable traits; they can only pass them on. Evolution does not occur within a generation. It occurs between generations". ~Although Lamarck was genetically incorrect, his idea was heritable traits were passed on that assisted the animlas to adapt and thrive in the new environments that were created.

4. Could Darwin have developed his theory of natural selection without the influence and ideas of this individual? Explain. (10 pts)

I can not say that Darwin would of or would not have developed his theory without Lamarck. Lamarcks time frame is 1744-1829 and Darwin did not began to realize the correlation to the animals and their environment, I beleive until the late 1830's. As Darwin wrote (pg 36) "It at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The result of this would be the formation of a new species"(F. Darwin, 1950, pp. 53-54). Darwin was basically stating what Lamarck had interpreted some years prior. Animal would lose/change what was not needed or desired in order to continue striving in the changing environment.

5. How did the attitude of the church affect Darwin and his eventual publication of his book  On the Origin of Species? (10 pts)
The attitude of the church affected Darwin and his publication because it Evolution, Evolution theories, ideas were considered atheism. Many believed and feared that if Evolutionary ideas were generally accepted "the Church would crash, the moral fabric of society would be torn apart, and civilized man would return to savagery" (PG 33)  (Desmond and Moore, 1991, p.34). Science and Religion are not easily manageable. both do explain, in their own ways, ideas and theories. Science can be tested over time and religious ideas can not. Most people be lived that evolution ideas and theories were depleting God and His creation of man kind in his own image.