The Facts of Evolution
The major theme of the article is the justification of Darwin’s evolution theory. The author also notes that historical sciences can provide valid evidence (as valid as experiments and observations).
The five general tenets Mayr outlined are as follows: evolution (species change throughout time), descent with modification (posterities are similar but not absolutely equal, which leads to modifications and ability to adapt to the changing environment), gradualism (species change quite slowly), multiplication of speciation (many modifications appear as species do not change in a similar way), natural selection (there is a struggle for existence, and the fittest survive).
Allopatric speciation is Mayr’s theory based on the assumption that some species become isolated due to various reasons (the change of habitat), and they change quite rapidly and in quite a distinctive way.
Punctuated equilibrium is the theory that explains why so few fossils of transitional species exist. The theory is based on the assumption that species are static (which creates equilibrium), but the changes in species are very rapid (punctuated), and, thus, the concept of punctuated equilibrium appears.
Vestigial structures occurred as modifications that turned out to be unnecessary in the course of evolution. Some examples of vestigial structures in humans are male nipples, male uterus, thirteenth rib, coccyx, wisdom teeth, appendix, body hair, goosebumps, extrinsic ear muscles, third eyelid (Shermer 22).
Evolution in Action
Charles Darwin was the scientist who developed the evolution theory, according to which all species change and evolve throughout time.
Natural selection is the mechanism that drives evolution. There are quite scarce resources (compared to populations of species), and species have to struggle for their existence. As a result, the fittest survive and give offspring.
People have a significant impact on species causing evolution. For instance, due to trophy hunting, bighorn mountain sheep now have smaller horns as hunters tried to kill sheep with bigger horns. Extensive use of antibiotics leads to the development of drug-resistant bacteria.
Although Darwin believed that evolution and modifications need a lot of time, modern scientists believe that changes can happen quite rapidly. Researchers found that a significant modification occurred in sockeye salmon within thirteen generations, which is a rapid change (it took only several decades).
The Viral Superhighway
The first epidemiological transition occurred about ten thousand years ago when people started farming (rather than continued leading a nomadic way of life).
The second transition was identified in the 1970s when antibiotics started being used to treat diseases. The third transition took place two decades ago when new illnesses started appearing due to globalization and the use of antibiotics. The first shift was one of the most dramatic as humans exposed themselves to various illnesses through the domestication of animals and because of the high density of living.
The Perfect Plague
The article dwells upon human pandemic diseases and the relevance of natural selection to the treatment of various disorders.
To survive, microbes have to be able to spread and move from one person to another.
Microbes ‘make’ their victims export them through coughing, sneezing, open sores. From these sources, microbes appear in inhale ways of other people, in water, and on the skin of other people.
The virulence can be favored if the victim happens to spread billions and trillions of microbes to other people just throughout the course of the disease (from the moment of infection to the person’s death).
African hunters were infected by mosquitoes who bit infected monkeys. The hunters brought the infection to their villages, and the disease spread very quickly. African hunters also cut themselves when hunting, and, in that way, they expose themselves to infected blood of killed animals.
Disease forecasting is predicting the development of pandemic or rather identifying a rapidly spreading disease and localization of this disease. This is crucial as it enables researchers to prevent the spread of the disease and microbes further mutations.
Curse and Blessings of the Ghetto
Tay-Sachs is the disease that mainly targets Eastern European Jews though it can also occur (infrequently) in all other ethnic groups.
The disease affects carriers of the Tay-Sach gene. This gene is common in the population that was quite isolated due to many reasons, and the gene developed as an attempt to resist tuberculosis.
The ability to resist tuberculosis by heterozygous individuals is referred to as the blessing of Tay-Sachs.
The curse of the ghetto is that people are exposed to numerous diseases due to the density of population, and its blessing is that people may develop certain tools to resists some diseases.
Ironing It out
The article dwells upon hemochromatosis and its outcomes as well as origins. It also provides reasons why such a dangerous genetic feature persists in people.
Hemochromatosis is a hereditary disorder that affects the way the human body processes iron. The body is suffering from the disease stores iron ‘thinking’ that it is not enough iron in the organism. The excessive amount of iron damages joints, major organs, and the person eventually dies. It is bred in humans’ genetic code as the accumulation of iron is crucial for people’s survival, and there are ways to control its accumulation and distribution.
Works Cited
Shermer, Michael. “The Facts of Evolution.” Annual Editions: Physical Anthropology. Ed. Elvio Angeloni. Guilford, CT: McGraw-Hill/Dushkin, 2014. 17-24. Print.