Cephalization In Mammals

In the neural tube, neuroepithelial cells line the ventricular wall, are densely packed, and form the ventricular zone. They will eventually divide and form radial cells which act as stem cells and provide scaffolding. While continuing to migrate, migrating cells then differentiate into neurons and glia. The development of the brain can now be considered, from a cellular viewpoint, as a sequence of six different stages, most of which happen during prenatal life. We first start off with phase 1, neurogenesis, which is the mitotic division of nonneuronal cells to produce neurons, phase 2, cell migration, is the massive movements of nerve cells or their precursors to distinct areas of the nervous system. The 3rd phase is cell differentiation, the changing of cells into distinct types of neurons or glial cells. Then we have the 4th stage of synaptogenesis, the formation of synaptic connections, which are equal to small gaps through which nervous system cells communicate to one

Others see these differences as variation within the human species. As pointed out in both the book, The Past in Perspective, and the film, differences included projecting brow ridges and face, and an occipital bun, a projection in the back of the skull. It is concluded that the occipital bun evolved to accommodate brain growth. However, skulls are far too complex to give simple answers as to why certain features, such as the occipital bun, evolve the way they do. The more we understand how skulls grow and function, the better we can understand the complexity of the brain and be able to answer these

       In addition, the macro evolutionary enlargement of the hominid brain correspond with other mammals and body size (Henneberg 748). The micro evolutionary decrease in human brain size during intellectual and cultural achievement (Henneberg 748). The lack of intraspecfic correlation between brain size and measured human intelligence is not in result of its size (Henneberg 748). It is also probably not in result of its gross anatomical structure (Henneberg 748). Human encephalization may be more a result of the reduction in the relative body size as opposed to the increase in brain size (Henneberg 748).

The Cerebellum is the part of the brain at the back of the skull in the vertebrates. Its function is to coordinate and regulate muscular activity. The Cerebellum is located behind the top part of the brain stem, it is where the spinal cord meets the brain, the Cerebellum is made of two hemispheres. The Cerebellum receives information from the sensory systems, the spinal cord, and other different parts of the brain, and then it also regulates motor movements. The Cerebellum coordinates voluntary movements such as posture, balance, coordination, and speech, and then it results in smooth and balanced muscular

Brain organs which are often used get larger while the less used get smaller making the skull to have indentations or bumps due to shrinking of some parts and enlarging of others. This according to phrenology show specific areas

Central nervous system (CNS) is composed of brain and the spinal cord. Neurons constitute a major part of the developing CNS. An axon is an extension of a neuron. The brain grows as a swelling at the front (rostal) end of the neural tube and later leads to become a spinal cord (1,2). Development of the CNS involves many complex mechanisms beginning at the onset of transformation of a single layer of ectodermal cells, the neuroectoderm until the end of the differentiation process resulting into highly complex structure involving variety of neural cell types (1,2). A large number of cell types need to be arranged spatially and temporally to form a complex structure during an

Evolution is the inheritance of traits over generations. Originally, my view on evolution was that positive new traits are passed down from generation to generation. The importance of evolution is that it allows an individual to better survive using newly inherited traits. These traits aid in one’s overall fitness. To give an example, a type of bird may evolve to have longer wings if it will better allow them to survive in their environment. Throughout the Capstone course, I have learned about the different types of evolution, and why certain changes arise in different species. The Capstone paper has enabled me to research areas of evolution within the hominid species, which gave me a better understanding of the advantages and limitations of evolution. This position statement will discuss what I have learned about evolution while writing my final paper, and attending class lectures.

It had seem to show outlines of the Broca’s area which is located in the frontal love of the left hemisphere which its functions are linked to speech production. If this were to be true the neurological evolution was already happening since the time of Homo Habilis two million years ago. Tobias had also though to believe because the Broca’s area was somewhat developed that this would allow the possibility to have neurological capacity to control the vocal tract musculature. If the brain could develop the Broca’s area this early on the linguistic vocalization development would be limited. Because the cranial capacity were larger in Homo Habilis but no difference in body size to the earlier hominid Australopithecus shows the encephalization in that the Pliocene era played an important role for neurological evolution for

A popular focus for evolutionary research has been the evolution of the human brain. Such research has sought to answer the questions of why our brains evolved to be as large as they are and how this increase in brain size came to be, given the massive energy requirements of neural tissue. Encephalization quotients refer to the size of the brain compared to the size of the body; as brain size increases and body size decreases, the encephalization quotient becomes larger. As would be expected, homo sapiens possess the largest encephalization quotient of all known species on Earth, being 6 times larger than the average mammal (Martin). The evolution of larger brains, which are more metabolically expensive, was made possible by a reduction in

Paleoneurologists are scientists who study the evolution of the brain. They use endocasts to study the brains evolution over multiple years. Endocasts give them a lot of information, such as, size, shape, and surface morphology. http://mentalfloss.com/article/70306/tracing-evolution-human-brain-through-casts-inner-skull

Homologous structures are anatomically and functionally similar structures in different species, which act as evidence that they have descended from a common ancestor. An example of homologous structures in the brain between different taxa are the palaeostriatum primitivum of the avian brain and the globus pallidum of the mammalian brain13. These structures show that is an evolutionary relationship between birds and mammals. In addition to looking at homologous structures, it is possible to look at the adaptive radiation of species which have been evolved independently and find examples of convergent evolution. Convergent evolution refers to when a trait evolves in different species independently of each other. Evidence of convergent evolution in turn proves the natural selection mechanism of evolution since it demonstrates that certain traits provide fitness, allowing the trait to survive in succeeding populations. There is evidence to show that certain aspects of brain anatomy in insects have evolved independently of each other in species such as butterflies and bees. The name of the specific piece of anatomy that exists in both organisms are is the corpula pedunculata or “mushroom bodies” (MB) which are responsible for navigation and spatial learning14. Both organisms had the necessity for an organ responsible

The cerebellum is a larger portion of the brain which are all vertebrates. It is ten percent of the brain. The cerebellum can be separated in three parts, the midline vermis, and two lateral hemispheres. The hemispheres are large compared to other organisms and are used for motor control. The vermis is used for controlling muscle tone and level of force. Over all the cerebellum main functions are to control the cognitive

As mentioned previously in Jeeves and Brown’s book, the field of evolutionary psychology is one of two divisions within neuroscience receiving a lot of attention for its cutting edge research and controversial conclusions. At the beginning of chapter 6, the authors reference evolutionary psychology’s growing popularity, citing particular news articles in prevalent magazines such as Times and Der Spiegel. However, these snippets of debated discoveries in evolutionary psychology should be interpreted with a keen eye. With so much hype and excitement surrounding the field, the scientific basis of evolutionary psychology becomes, at times, distorted. Thus, Jeeves and Brown discuss the true scientific roots of evolutionary psychology in chapter

There are two main origin theories on the evolution of the nervous system. These two concepts are monophyly and polygenesis. Monophyly states that, all neurons came from a single ancestry, while polygenesis states that there is more than one independent ancestry of neurons among species. The concept of monophyly is the groundwork of all biology (Moroz, 2009). The lineage of the nervous system present in all animals can be traced back to a common ancestor (Ghysen, 2003).

17. How do the pre- and postganglionic neurons of the ANS differ in embryonic origin? Preganglionic neurons of the ANS develop from the neural