Mary-Clare's Evolution Blog

 Chapter 11 of Dr. Tatiana's book begins with the rather taboo idea of inbreeding. Instead of immediately condemning the idea, Dr. Tatiana claims that it is not always a surefire way of a species becoming incapable of carrying on. For many creatures, it is not harmful to subsequent generations. Pinworms and mites are examples of species that can safely interbreed. We learn that inbreeding can be costly when harmful recessive genes are present in family members who then reproduce. The likelihood of two close family members carrying the same harmful genes is much higher than it is between two completely unrelated strangers. Sick offspring do not reproduce the way that healthy offspring can. From this, we know that it is usually not ideal for mammals to mate if they do not have to mate.  'Body size, inbreeding, and lifespan in domestic dogs' further adds information of how inbreeding can negatively affect populations where inbreeding does not aid in reproductive success. Domes

 Dr. Tatiana spends some time in chapter 9 explaining homosexuality in the animal kingdom. She notes that it is common amongst multiple species and can be caused by a handful of factors. She mentions that it could be due to desperation, for pleasure, genetically based, for power, or as a reproductive suppression behavior. Our question: "how are high numbers of homosexuality maintained in high numbers" is touched on in the book. If there is a genetic basis, genes can still be passed on if individuals who practice homosexuality are not exclusively homosexual. This means that they are still able to reproduce and pass their propensity to be homosexual onto their offspring. Dr. Tatiana also suggests that genes for homosexuality could be maintained if natural selection favors them. When this book was written less was known about the genetic basis of homosexuality.  'Evolutionary Origins of Homosexuality' discusses numerous pieces of evidence that supports an argument that h

Dr. Tatiana covers female cannibalism behavior extensively. She gives several possible hypotheses as to why females are eating their mates. Females eat males in order to get the nutrients they need for their babies. Females eat males because they are a substantial meal. Females eat males because they are not fit enough to copulate with her and thus pass his genes onto a subsequent generation. Whatever the reason, usually in these populations have males that are great at escaping a female's hungry desires and males that don't make it out in time. Something that Dr. Tatiana did not cover was the affect the consumption of males could have on the population.  'Sexual cannibalism and population viability' sought to answer how sexual cannibalism could possibly affect the population. It states that there are two negative consequences that sexual cannibalism can have on the population: 1) in every case of cannibalism, an adult male that was capable of mating was removed from th

 Dr. Tatiana briefly discussed 'musth', a period of time in which a male elephant is afflicted with extremely high spikes in testosterone. These spikes, which can last anywhere from a few days at a time to four months, have strong influences on the male's behavior. Dr. Tatiana mentions that it can increase aggression and cause males to pick fights with other males. Fights can get so intense, that one male gets killed. Usually they end with one male chasing the other off for several miles. 'Musth and its effects of on male-male and male-female associations in Asian elephants' notes that musth is a roving behavior. Female elephants live a completely different lifestyle than male elephants. Females spend their entire lives in their natal clan, whereas males usually break off from their clans during puberty and live in solitude for the rest of their lives. Females also have a very short period of time where they are able to reproduce because they take 10 years to sexual

 The paper that I examined focuses on the possible genetic component of female promiscuity. Dr. Tatiana mentioned in her first book, "If a proclivity for promiscuity is genetic, then yes, promiscuous behavior will become more common if loose females tend to have more children than their monogamous peers... Unfortunately, though, we don't know much about the genes that influence female sexual behavior in any animal...". Fortunately, it has been 20 years since she wrote that and people have taken time to do a little more research on this matter.  Researchers distinguished two hypotheses for how the genetic constraint influences female promiscuity. The first hypothesis states that there are homologous traits for female and male promiscuity, and that alleles that increase promiscuity in the population are retained by males. Females that inherit these alleles exhibit promiscuity even though it does not benefit them (this was known as "intrasexual pleiotropy". The sec

Introduction Acne vulgaris is a condition of the skin that causes blemishes to appear due to the blockage of pores by dead skin cells, sebum, and bacteria. These blemishes can come in the form of pimples, blackheads, white heads, and cysts. Acne vulgaris is the most common form of acne, with 80% of the US population experiencing some form of it in their lifetime (Jaggi Rao, 2020). It is most common in adolescents (ages 10-19), but can occur in people of all ages. As our environments have made rapid transformations towards modernity, humans have struggled to adapt to certain changes. Certain environmental changes that have occurred include: diet, exercise, cultural changes, and the development of technology. These changes have caused humans to be more prone to develop diseases that did not appear in early Homo sapiens. Genes that can cause one to become predisposed to one of these environmentally linked diseases were never selected against, which is why they are so prevalent today. Thes