There is evidence that other species have adapted better to modern environments than humans. They colonize their new habitats and adapt to the changes in their environments than humans. In the modern age, people can eat processed foods because they are cheaper and accessible than healthier natural foods. Nutrition and diet is an essential factor in influencing reproductive success especially the ratio of carbohydrates to proteins. This ratio depends on the lifespan stages of an individual. Intake of proteins during eclosion can provide a lasting ability to reproduce in males and may not after that influence reproductive ability. Research also discovered that low protein intake in men leads to small numbers of insemination and copulations. Carbohydrates were found to influence the duration of intercourse (Hunter, 414)
Humans have not adapted well to the current environment on the issue of diet and eating healthy foods. Due to improper diets, parents have propagated transgenerational problems influenced by the situation to their children causing metabolic disorders and other chronic diseases like cancer. The close relationship between a pregnant mother and her child in gene expression especially before conception relating to the health of a fetus is shown through the effects of smoking and use of drugs. The eating behavior of a pregnant mother may influence the genes of her fetus and future health of her child (Hunter, 415).
In the era of hunting and gathering, humans transitioned to an agricultural lifestyle by taking up farming and keeping animals. There was the overall success in reproductive fitness. However, the rate of mortality was high due to sedentarization and infections. Humans fed on raw and healthy foods in this generation. An environment of evolutionary adaptedness refers to circumstances in the present situation where a specific species is naturally adapted. According to John Bowlby, humans lived in groups of hunters and gatherers for more than 99% of human existence of at least one million years.
The evolutionary mismatch means that traits that were useful in the past have evolved to become maladaptive because of changing environments and rapid changes. It represents the fact that characteristics acquired in one setting may be disadvantageous in another situation. Due to natural selection, nature that is described by the immediate environment determines the persisting traits in a population of species. According to natural selection, features that are disadvantageous are weeded out making the community more adaptive to the new environment. Such changes in traits can be based on genetics and mutation factors in response to changing environments.
People can spend most of their time sited without exercise because of occupation. Factors environment contaminations, physical and socioeconomics affect reproductive fitness of an individual by their eating habits. A decrease in cooking skills, busy schedules, technological advancements, medical conditions, social, and environmental issues have also contributed to poor diet.
Environmental factors can influence the expression of a gene. It is not easy to relate genetics and environmental factors on fertility and reproduction fitness in humans because of other factors like culture, economy, and social. However, in focusing on a population with similar lifestyles, it was discovered that autosomal, dominance variances and X-linked additive traits contributed to reproduction. (Loyd et al., nd). New environments can cause a mismatch when an organism is adapted to live in an ancestral environment. In modern ecosystems, psychological and physical factors exhibit mismatch. Birth rate, the number of offspring one can get, and the span of fertility are determinants of reproductive fitness in humans that depend on the number of genes that can be transmitted to future generations. The availability of nutrients, harmful substances, and external environmental factors like temperature and rain can affect the survival of a species by influencing reproduction. (Loyd et al., nd). Psychological stress, environmental pollutants, and impurities such as tobacco smoke, poor indoor air quality, and exposure to video display terminals have been detected to cause infertility in women. The changes in the environment were found to affect the reproductive fitness especially due to the exposure to chemical contaminants because of the nature of the occupation.
Diet can affect the genes and how they get expressed. Therefore, diet can be a force to drive human evolution. According to Loyd et al., "genes that control metabolism are closely related to diet." Epigenetic changes are associated with environmental factors that affect the genes. They take place during embryonic development and throughout an individual lifespan.
Non-genetic inheritance is a mechanism used to modify gene expression due to epigenetic changes in mammals and plants. The genetic imprinting takes place on a few numbers of genes if the mother's allele is inherited and silenced. The inherited copy of the gene is sensitive to the changes in the environment. Genes that have resulted from inheritance due to the sexual conflict have been discovered to control metabolic functions like eating and processing nutrients. (Loyd et al., nd). Genetic imprinting is close-related to maternal inheritance because it has been proven that pregnant mothers who have diabetes or are overweight have more chances of having obese children.
Work cited
Hunter, Philip. "We are what we eat: The link between diet, evolution and non‐genetic inheritance." EMBO reports 9.5 (2008): 413-415.
Lloyd, Elisabeth, David Sloan Wilson, and Elliott Sober. "Evolutionary mismatch and what to do about it: a basic tutorial." ms. in final draft, to submit to Evolutionary Applications (waiting for other articles for issue) (2011).
