What did Evolution do to Our Muscles - Essay Example

Introduction Research indicates that humans and chimpanzees laws shared an ancestry 5-7 million years ago. Genomic differences have played a significant role in heralding differences between humans and chimps. In the entirety of human history, natural selection has played a critical role within the development of modern man. Different species have diverse strengths to adjust to their environment. Over millions of years, species adapts to the environment to ensure that the traits best suit the species to their environment. Chimpanzees can be perceived the closest living relative of humans sharing about 95-98% of the DNA. However, humans do not come close to comparing to chimps’ strength and the percentage points that humans and chimps differ are extreme due significant anatomical and physiological differences. The way in which muscles are attached to bones is different in chimps compared to human, which enables chimps to have enhanced mechanical advantage in both arms and strength. The paper explores why chimps enjoy powerful strength relative to humans. Discussion Evolution changes manifest on the genetic levels passed from one generation to another. The changes manifest at the genetic level overtime as the organisms’ genes mutate and/or recombine within diverse ways during reproduction and are passed to future generations. Scientific evidence demonstrates that the physical and behavioral traits shared by humans emanated from apelike ancestors and evolved overtime. Bipedalism remains one of the most prominent human traits highlighting how humans have evolved. Other traits include development of a large and complex brain, capacity for language, and capability to make and utilize tools. Muscle contractions form the basis of movement within a majority of the species (Muehlenbein 137). Chimps are stronger that humans centers on the fact that they do not have closely as many fine control over their muscles. Humans enjoy the capability to d precise things such as operating complex machinery, which necessitates choice of minute sizes of muscle fibers. Hence, humans sacrifice strength over precise control of their muscles. The nervous system exercises significant control over the muscles relative to the chimp muscles. Studies have revealed that chimps have relatively reduced grey matter within their spinal cord compared to humans. Spinal grey matter features a significant amount of nerve cells that link to muscle fibers and control muscle movement. This details the process that allows finer control of the muscles. As a result, chimps possess more strength relative to what they need owing to their lack of control (Aiello, Christopher, and Joanna 226). Humans enjoy a built in safety system that aids in safeguarding against damage to muscles. Studies have demonstrated that chimps are incredibly strong and fast to the extent that humans may be easily overpowered when in confrontation with chimps. Nevertheless, studies have not conclusively resolved whether the variation emanates from higher density of contractile material, or due to the variations within the contractile machinery. Studies indicate that chimps have almost twice (pound for pound) the strength of humans, especially when pulling weights. Chimps also beat humans in leg strength despite humans’ reliance on legs for locomotion. Studies have proven that chimpanzees surpass humans, when it comes to strength relative to size and the core difference between the two emanate from muscle performance (Lieberman 234). In chimps, the muscle fibers adjoining the bones are deemed to be the source of strength of humans and chimps, are much elongated and denser, which enables chimpanzees to generate more power while utilizing the same range of motion (Muehlenbein 138). However, unlike humans, chimps enjoy less control over their muscles, which necessitates that chimpanzees utilize more energy than necessary. The lengthy muscle fibers, as the source of chimps’ strength, impedes on the capability of chimps and other apes to swim. The evolutionary context Human evolution represents the evolutionary process yielding up the appearance of modern man. Human evolution features several morphological, physiological, developmental, and behavioral changes that have manifested since the split between chimpanzees and last common ancestor of humans. The most prominent of these adaptations relates to bipedalism, enhanced brain size, reduced sexual dimorphism and lengthened ontogeny. DNA and anthropologic evidence consider modern humans primate, and the descendants of ape-like species. The development of the modern humans has taken place through thousands of years and has yielded to unique adaptations resulting from ecological pressures that man has faced. The environmental, dietary, and behavioral variables have coalesced to make the modern human muscular system differ significantly from that of their evolutionary ancestors. As is the case of all evolutionary adaptations, the human muscular system has evolved in an effort to increase survivability. Muscles and the accompanying ligaments and tendons within the body aid in numerous functions, which makes it evident that human behaviors and decisions, grounded in what they operate. It is essential to note brain development has played a critical role; which has guided the development of muscle functions and structure within humans (Lieberman 233). The adaptation to full-time bipedalism by human’s ancestors can be cited as the core argument for the adaptations of human’s muscle structure and functions. The evolution of human bipedalism can be linked to morphological alterations to the human skeleton such as alterations to the human skeleton inclusive of changes to the organization and size of the bones on the foot, leg length hip size and shape. The muscles of the human body work the skeletal system under voluntary control and are concerned with posture, movement, and balance (Bogin 138). The primates came into the primitive quadrupedal stance and locomotion; however, since their manifestation within the Late Cretaceous Period, some have adjusted locomotor systems to center on the utilization of arms for propulsion via the trees. The most tremendous expression of such skeletal adaptation within primates can be viewed within modern gibbon family. Modern humans closely connect to chimpanzee, the orangutan, and the gorilla. There is minimal direct fossil evidence on the shared ancestry of modern humans to chimpanzees and gorillas; hence, inferences regarding habitat and locomotion have to be made (Aiello, Christopher, and Joanna 227). Muscles of the lower limb The significant muscular changes directly connected to shift to bipedal locomotion can be viewed within the lower limb. The most evident skeletal changes can be found in the length of the hindlimb, the change within the shape of the knee joint, the changes within the length of the hindlimb, and the development of the heel. The hind limbs of chimpanzees are comparatively short for their body size relative to modern human proportions. The changes that manifested within pelvic bones may not be all directly connected to the adaptation in locomotion, although they are resultant of it. Humans, in some way, have stronger muscles relative to chimps. Humans have strong bottom muscles that are mostly absent among chimps. This derives from the fact that the muscles pull the leg back at the hip when humans are walking on two legs. Since chimps do not walk on two legs, the muscle may not needed, which in turn, makes it much weaker. One of the significant strengths that humans enjoy centers on their capability to run upright. The transition to upright walking within the initial stages of hominid evolution requires a considerable range of adaptations of muscles and skeleton. Strong upper body muscles would render humans inefficient at running by altering the center of gravity making it higher (thus less stable). Evolution relates to developing the right characteristics and humans is highly likely to lose strengths, to some level if they remain unutilized. This explains why humans have become weaker within their upper bodies since they do not need require much energy to sustain the muscles, and would find it difficult to gather enough food. The development of bipedality occasioned the freeing the hands from the core involvement with locomotion and support allowed the development of manual dexterity. The human upper limb has preserved an overall generalized structure adapted to upright existence. This also yielded to a substantial enlargement of the brain, which also impacts on the skull, and consequently, the musculature of the neck and head. A larger brain has a direct correlation to the pelvis based on the need for a bigger pelvic inlet and outlet for the birth of comparatively bigger-brained young. An enlarged pelvic cavity translates to differentiated hip joints, which in turn, subjects the significant forces when weight is subjected to one leg during running and walking. However, the muscles are pertinent in to sustain balance as is the knee extensors, which have been realigned and repositioned such as the muscles of the calf. Muscles of the compartments of the modern human leg play a part in making the foot a stable platform essential to adaptation to walking over rough ground. Conclusion Research implies that humans may lack the strength of chimps since the nervous system of humans exerts high control over the muscles compared to the case of chimpanzees. One possible explanation on why chimps are stronger than humans lies in the fact that great apes have more powerful muscles. Biologists have unearthed differences within muscle architecture between humans and chimpanzees. Although, chimps weigh much less compared to humans, the bulk of their mass is concentrated within their powerful arms. Biologists have indicated that that chimp’s skeletal muscle fibers have elongated fibers relative to the human equivalent, and can generate two times more work output within a broad range of motion. One explanation for the differential strength between chimps and humans can be linked to the nervous systems that exert increased control over the muscles. The fine control limits strength, but allows humans to undertake human tasks. The surplus motor neurons enable humans to engage minimal portions of their muscles at any given time. References Aiello, Leslie, Christopher Dean, and Joanna Cameron. An Introduction to Human Evolutionary Anatomy. London: Academic Press, 2002. Print. Bogin, Barry. Patterns of Human Growth. Cambridge [u.a.: Cambridge Univ. Press, 1999. Print. Lieberman, Daniel. The Evolution of the Human Head. Cambridge, Mass: Belknap Press of Harvard University Press, 2011. Print. Muehlenbein, Michael. Human Evolutionary Biology. Cambridge: Cambridge University Press, 2010. Print. Read More