Macroevolution Vs Evolution

1. Define analogous and homologous traits and provide an example of each.

Animal classifications and the field that specializes in it is called taxonomy. Traditionally, organisms are categorized according to their physical similarities. This was the first systematic classification constructed by Carolus Linnaeus in the eighteenth century. Currently, basic physical similarities are considered, however, for these similarities to be of any help, they must reflect evolutionary descent. Furthermore, "structures in organisms that are shared by species on the basis of descent from a common ancestor are called homologies (Jurmain et al. 110)." Homologies are illustrated by the similarities found in the forelimbs bones of the following land vertebrates
(tetrapods): chicken, porpoise, stem reptile, bat, and human (110). On the other hand, there exists analogies which are "similarities between organisms based strictly on common function, with no evolutionary descent (Jurmain et al. 110)." To demonstrate, butterflies and birds have wings and are used for the same purpose (to fly), however, both butterflies and birds developed independently from each other, which is also known as homoplasy (Jurmain et al. 110). Nevertheless, animal classification is an integral part of our ability to understand where we all fall within this vast world, and analogies and homologies aid taxonomist in bringing accuracy to the table.

2. Explain the differences and similarities between microevolution and macroevolution, giving an example for each one.

Physical anthropologists try to answer many questions through the study of evolution, variation, and adaptation.
Furthermore, seeing the word evolution most of us think it is the development of a new species, however, that is not the only form of evolution. Evolution "is an ongoing biological process with more than one outcome (Jurmain et al. 5)." In other words, evolution is a change in the genetic makeup of a population from one generation to the next and it can be divided into the following categories: macroevolution and microevolution (Jurmain et al. 5)." To further illustrate, some genetic changes in populations do result in the appearance of a new species, also known as speciation, and particularly seen when those populations are isolated from each other (Jurmain et al. 5). This level of evolution is known as macroevolution. On the other hand, there are genetic changes within a given population and while these changes may not lead to speciation it can cause populations of a species to vary from one another in the frequency of specific traits. Evolution such as this is known as microevolution (Jurmain et al. 5). Moreover, the similarities between macroevolution and microevolution are that they both heavily rely on the following evolutionary factors: mutation, gene flow, genetic drift, and natural selection (Jurmain et al. 97-102). A great example of microevolution was described in the nineteenth century by Charles Darwin when he discovered 13 varieties of finches and
with further scrutiny concluded that there existed beak variations in the finches that he collected from the Galapagos Islands (Jurmain et al. 35). The geographic isolation over a few generational periods caused microevolution to occur. As a result, the finches on the South American mainland compared to all the different variations of finches on the other islands possessed beak variations such as shape and size (Jurmain et al. 35). Nevertheless, an example of macroevolution is speciation that takes millions upon millions of years to occur and such an example is Chordata organisms developing into two phyla which are vertebrata and invertebrate chordates and going on to speciate even further into the taxonomy chart we have today. (Jurmain et al. 109). In addition, Homo erectus being one of our closest relatives, is also definitely a great indicator of the presence of macroevolution (Jurmain et al. 301).

3. Which primate traits are likely to be adaptations to arboreal lifestyles?

The primate traits that are likely to be adaptations of arboreal lifestyles are the following: 1) a tendency toward an erect posture and all primates show this tendency to different degrees (Jurmain et al. 137), 2) lack of dietary specialization, therefore, retaining a generalized dentition, 3) decreased reliance on olfaction which seen as an overall reduction in olfactory structures of the brain (Jurmain et al. 138), 6) increased reliance on vision with an increased level of depth perception and stereoscopic vision (Jurmain et al. 138), 5) reduced number offspring coupled with more efficient fetal nourishment and longer periods of gestation (Jurmain et al. 139), and 6) the tendency toward diurnal activity patterns and this seen in most primates and only the following exhibit nocturnal activity patterns: "lorises, tarsiers, one monkey species and some lemurs (Jurmain et al. 139)."

4. List five traits that distinguish lemurs and lorises from the anthropoids.

The order Primates includes all primates and under this order there are two suborders one of which is Strepsirhini and the other Haplorhini (Jurmain et al.
146). The suborder Strepsirhini includes the infraorder Lemuriformes, which includes lemurs and lorises, while the suborder Haplorhini consists of two infraorders: Anthropoidea and Tarsiiformes. The infraorder Anthropoidea, in particular, comprises of Anthropoids which include all monkeys, apes and humans (Jurmain et al. 147). Even though lemurs, lorises, and anthropoids are all primates there exist reasons why lemurs and lorises are classified in a different suborder and infraorder from anthropoids. Five traits of lemurs and lorises that distinguish them from anthropoids are the following: 1) lemurs and lorises have increased reliance on olfaction, which is reflected in the presence of a moist fleshy pad on the end of their nose, called a rhinarium. In contrast, anthropoids have a reduced reliance on olfaction, indicated by the absence of a rhinarium and a reduced size of the olfaction related structures in the brain. 2) lemurs and lorises have eyes placed more to the side of the face indicating a reduced reliance on vision that is not completely stereoscopic, while anthropoids have an increased reliance on vision, with eyes placed more to the front of the face (Jurmain et al. 150). Nevertheless, anthropoids have an even more complete stereoscopic vision (Jurmain et al. 151). 3) lemurs and lorises have a special derived
trait called a "dental comb" formulated by forward-protruding lower incisors and canines (Jurmain et al. 148). The "dental comb" is primarily used in both grooming and feeding (Jurmain et al. 148). On the other hand, anthropoids have generalized dentition indicated by the absence of the forward-projecting incisors and canines (Jurmain et al. 152). 4) lemurs and lorises have a smaller average body size compared to anthropoids. Lemurs range in size from 3 inches (Madame Berthe's mouse lemur), to the indri (Jurmain et al. 148), 2 to 3 feet long (Jurmain et al. 149). 5) lemurs and lorises, unlike anthropoids, have "two distinct bones joined by cartilage at the middle of the chin (Jurmain et al. 152)." On the other hand, anthropoids have a "fusion of the two sides of the mandible at the midline to form one bone (Jurmain et al. 151)." Nevertheless, there are five traits that are present with in lemurs and lorises that exemplify why lemurs and lorises are distinguishable from anthropoids.

Work Cited
Jurmain, Robert, et al. Introduction to Physical Anthropology . Wadsworth Cengage Learning, 2014.