Argumentive Biology Paper: Are Humans Still Evolving? (Essay Sample)

Biology essay
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Abstract
Evolution is one of the most important topics, which addresses journey of primates taking million years to develop to anatomically modern human. This essay seeks to highlight some of the reasons that man is still evolving despite advancement in transport, health sector, communication, social and cultural values and agriculture. The main drive of current evolution of man is genetic variation caused by spontaneous mutations. The beneficial variants of mutation confer certain advantage to the population and traits are passed to the next generation. Natural selection still holds to the modern man as the beneficial traits are conserved and passed to the next generation through inheritance. It can be concluded that man is still undergoing evolution.
Introduction
Evolution refers to change in characteristic of a given species over several generations. Natural selection is believed to be driving force for the survival of adapted species; thus, evolution occurs. Survival for the fittest plays a major role whereby organisms resistant to changing conditions emerge strong and are able to survive and pass traits to their offspring. The pressures for natural selections include diseases, drought, lack of food and poor housing. These pressures allow adapted animals and plants to survive and reproduce while non- adapted dies. There has been a great advancement in technology in recent times aimed at minimizing pressures on human such as health hazards and food insecurity. Increased knowledge has enabled humans to prevent diseases through either immunization or behavioral changes. However, I believe that humans are still evolving based on evidence from genetic studies on humans sampled cross the world. Mutation is reported to be rampant in human genome causing changes in structure of both normal gene and protein. Through natural selections, humans are able to survive such with mutations.
History of human evolution
It is believed that humans developed from primates to modern being, Homo sapiens, an upright walking and full of culture. The predecessors of human, Astralopithicus and Dryopiticus are extinct and believed to be related. Fossil has been source of valuable information suggesting existence o several species of primates leading to development s to modern human being. Carbon dating helps in estimating the period of time when they lived (Bodmer and Sforza, 1976). Charles Darwin wrote book on Origin of Species and highlighted that process of natural selection was responsible for survival of some organisms as others become extinct. The comparison of genetic material from human predecessors like primates and human explains evolution of man. Primates lived simple life characterized by sheltering in caves, feeding on fruits and wild animal hunt. With series of development both physically and mentally, primates evolved to humans taking million years. Brain development is the main source of human advancement in terms of technology and agriculture. I believe that as human continue to evolve; better things are to come. Below are some of the reasons that humans are still evolving.
Human genetic variation
Human genome project has documented significant genetic variations on sampled people. Single nucleotide polymorphism is the common genetic variation observed in humans occurring at certain region along the genome. Some mutations are fatal, for example if DNA mutation results in alteration of gene coding essential protein for survival. In such cases, individuals with such mutations dies of certain diseases associated with non-beneficial mutations and become distinct. On the other hand, mutations that confer resiatance to individuals are beneficial and confer ability to survive in case of disease outbreak. Such advantageous genetic variations tend to be passed onto future generations. Genetic variation can be detected by comparing DNA sequences from two individuals.
Mutation occurs by chance and the variant gene spreads across the population through inheritance. New gene variant amongst the population may affect expression of adjacent genes. In most cases, it prevents mutations in itself and surrounding DNA for it to be preserved and passed to many generations that follow. Scientist beliefs that gene mutations has resulted in evolution associated with brain development and strong immunity against pathogens.
Development of lactose tolerance
Lactose is a disaccharide found in milk and has to be broken down into simple sugars by lactase. It is believed that gene regulating lactase enzyme was shut down after lactation. This means only children digested lactose in milk while adults could not. This impaired lactose digestion in humans causes lactose intolerance associated with vomiting, bloating and diarrhea symptoms. Humans started domesticating goats, camels and cattle for milk and with time mutation occurred resulting in gene expression to produce lactase protein, which digest lactose. Mutation in regulatory DNA that controls expression of lactose coding gene is beneficial to adults who can now enjoy drinking milk. DNA mutation enabled switching on gene coding for lactase enzyme even after weaning throughout human life (Igram et al., 2007). Ability to drink milk up to adulthood is a strong evidence of evolution. The genetic variation favoring lactase production is believed to start from people from Europe. Cold climatic conditions and little sun exposure to Europeans led to seeking alternative source of vitamin D that is found in milk. Starvation due to lack of food led to use of cow’s milk and the people who were able to digest lactose survived.
Lose of wisdom teeth
Wisdom teeth are the set of molars that usually grows last. Hunter and gatherer fed on tough food including un-boiled meat, roots and nuts that were hard to crash therefore; they had strong jaw and complete set of teeth including wisdom teeth. Technological advancements has let to production of soft food for human consumption. Furthermore, currently there are knives for cutting and humans feed on soft food. This lead to evolution characterized by small jaws. Wisdom teeth may grow in some individuals while some are born without.
Disease resistance
In the past before introduction of antibiotics people used to suffer from infectious diseases like sepsis, leprosy, tuberculosis and malaria. Survival from infectious diseases was the selection forces, which enable resistant individuals to live. Survivors of such diseases passed genes to their offspring protecting them against such diseases thus ensuring perpetuation of the species. More genetic variations have been reported in humans that help combat infectious diseases. An example is caspase -12 gene, which poses higher risk to bacterial infections. The active gene when present in humans leads to poor immunity to fatal bacterial disease known as sepsis. With time, this ...