Analogy and Homology Blog Post

Prompt #1:

Part A: Two species that possess a homologous trait are turtles and lizards. I will will be specifically discussing the structure and function of tortoises. Tortoises are found in most continents of the world and are a type of turtle. They non-aquatic, slow-moving herbivores. They can be identified by a large bony shell which encapsulates most of their body and which they can retract into if threatened. They have four scaly legs equipped with claws used for digging and a tubular head and tail. The type of lizard I will be talking about is the bearded dragon. This lizard grows up to two feet long and has an omnivorous diet. It is covered in scales and is cold-blooded. It is relatively fast moving and possess long claws used to aid in climbing. It possesses bony horns that line it's head and the sides of it's body.

Part B: The homologous trait of these two creatures is their bony projections which are used for defense. These projections and their structure and use are widely different between these two species. Tortoises possess bony projections that cover most of their body forming a protective carapace or shell. Tortoises utilize this shell when threatened by predators who then have difficulty harming, killing, or consuming the tortoise due to it's bony shell fending off most attacks. The bony structure of the tortoise's shell protects it from harm by keeping the tortoise's vital organs protected. The bearded dragon utilizes it's bony projections very differently. The point of the dragons spikes is to either dissuade predators from trying to eat the dragon or even prevent them from doing so. Predators attempting to eat a bearded dragon would be faced with difficult since the dragon's spikes make consumption difficult. Additionally, the dragons spikes face down towards it's tail so a predator attempting to swallow a retreating dragon would have to contend with projection contrary to it's motion of eating easily resulting in damage to the predator. The bearded dragon utilizes it's bony projections to dissuade or fend off attacks from predators. These traits are exhibited differently because tortoises are much slower moving than other reptiles and thus need to take their protection with them. They have evolved to carry a nearly impregnable piece of armor wherever they go. Bearded Dragons, on the other hand, is somewhat more mobile and focuses on can escape from most predators but needs extra dissuasion techniques when caught. These traits are exhibited differently because bearded dragons seek to dissuade predators and tortoises seek to deny predators. The structure of shells are used for defense and the repelling of a predators of attacks while the spikes of bearded dragons are used for the dissuasion or harming of a predator.  

Part C: The common ancestor of both these species is an archaic reptile. This is evident because both creature possess bony projections, albeit displayed in different ways, are cold blooded, and occupy similar parts of the world. I know this ancestor possessed the trait of bony projections since they are still evident, in some way, in all of it's descendants. The tortoise evolved to possess a bony shell while the bearded dragon evolved to possess bony spikes. My claim of homology between a tortoise and a bearded dragon is supported by the fact that they post possess similar characteristics, specifically bony projections used for defense, while both being classified as a reptile.

Part D: 

 

Prompt #2:

Part A: Two different species that possess the analogous trait of tails is the tiger and lizard. Tigers are characterized by their hunting prowess and vivid orange, black, and white stripes. Tigers are a type of large cat often found in jungle areas. They are carnivores and rely on their stealth and brute strength to kill prey. They have long sweeping tails and are very agile. They have large claws and long teeth used for climbing and attacking prey. Western fence lizards are small, omnivorous lizards found in many parts of the U.S. They are covered in scales with distinct blue scales lining their belly. They possess a long tapered tail and have small claws used for climbing. 

Part B: The analogous trait of a tail is shared by the western fence lizard and the tiger. While one of these creatures is a reptile and another a mammal, both of these creatures use their tales for balance. the western fence lizard can often be observed jumping from rock to rock. The lizards long tail acts as a counterweight to it's protruding head and this helps it maintain balance when making long jumps. The tiger uses it's tale for much the same purpose. A tiger's tail extends it's center of mass increasing it;s stability and making it a more effective hunter. It also aids in climbing or transversal of difficult areas. These analogous traits exhibit similarities between species because they are used for the same reason. The lizard uses it's tail to maintain balance when moving and the tiger does the same. Both species are found in areas that are difficult to traverse: rocky areas in the case of the lizard and heavily jungled areas in the case of the tiger. These areas are very difficult to travel through much less hunt effectively in, that is why tigers and lizards evolved to have similar tails. The tails of lizards and tigers evolved to help them navigate in difficult environments which is an example of convergent evolution. 

Part C: I believe that the common ancestors of these species likely possessed a tail as well. Tails in the reptilian and mammalian families seem to be the rule rather than the exception. Humans themselves possess evidence of once having a tail. This trait is analogous because the two species in question because they are so fundamentally different. Not only are a tiger and a lizard very different physically, but also genetically. A western fence lizard is part of the reptilian family while a tiger is part o the mammalian family. While mammals did likely evolve from reptiles, the rift between the two families is so great and their diversity so extreme that this trait must be analogous.

Part D:

                    

                       

Prompt #1
I would argue that Georges Cuvier had the most impact on Darwin's development of natural section. However, his influence was both positive and negative as he had contentions that supported and rejected Darwin's hypothesis. His establishment of extinction as a fact contributed to the formation of the idea of natural selection. On the other hand, Cuvier's opposition to organic evolution contradicted one of Darwin's main focuses.
Prompt #2
Georges Cuvier was a successful and highly respected scientist. A few of his many achievements included the founding of vertebrate paleontology and the classification of animals into four sections. He was a vehement supporter of the idea of extinction and proved it as fact. He also held the belief that animals could not change or evolve physically as doing so would violate their physical structure leading to their demise.
Prompt #3
The point provided that has the most impact in relation to Darwin and Cuvier is the statement "Individuals do not evolve, populations do." Cuvier strongly apposed any idea or proposition of physical change in animals since he believed it would compromise the entire physical structure of the animal and was therefore and impossibility. Darwin demonstrated that Cuvier's theory was incorrect, Darwin showed how animals adapted physically to their environment through evolution and natural section. While this was a negative example, Cuvier also had a positive contribution to Darwin's work. Cuvier established that extinction was fact and Darwin built on this in his "Survival of the Fittest model", showcasing that only well adapted animals survived. This point is best highlighted int he phrase "In order for natural selection to occur, reproduction must occur."   
Source Used: https://ucmp.berkeley.edu/history/cuvier.html
Prompt #4
Darwin could have developed the theory of natural selection without the help of Georges Cuvier, though his contributions did help support part of his research. Cuvier's main contention was that animals cannot physically evolve something Darwin refuted. That being said, Cuvier did prove that extinction was prevalent and could be observed. Extinction was a large part of Darwin's theory since it is what he proposed happened to species who did not adapt and evolve in relation to their environments. 
Prompt #5
While Darwin himself was religious, though often in turmoil over his faith, he often and issues with the church in regard to his discoveries. The church was a very powerful institution in society at the time and had a long held belief that the world was thousand of years old rather than Darwin's millions. Darwin found himself at odds with the church in regards to his discoveries and faced some censure, defamation, and hardship in regards to publishing his theory. While his discoveries were circulated, they were not as wide spread as other scientific discoveries due to church overreach and Darwin's own uneasiness in regards to religion.