mqpham's blog

Neanderthals and Denisovans were prehistoric humans. Neanderthals lived in Euope and Western Asia about four hundred thousand years ago and were extinct fourty thousand years ago. A distantly related group called the Denisovans originated in Asia. Evidence suggests that modern humans and prehistoric humans overlapped for a period suggesting interbreeding. DNA evidence reveals that there are parts of the human genome shared with the prehistoric humans. In modern African populations, the ressemblence between Africans and Neanderthals is nearly zero or zero, but is found to be at one or two percent in populations from Europe and Asia. Denisovan DNA is found to be lower than four to six percent in Asian populations and undetectable in other parts of the world. The genetic information found from prehistoric humans reveals the differences between modern humans and extinct prehistoric humans. It also reveals that certain variations in phenotypes and to some extent, risk of diseases (though still under study) may be identified. This however, does not reveal how "evolved" modern humans are, nor does it reveal practical information on assessing individual's health.

Speciation is the evolutionary process by which new species arise. Two types of speciation are sympatric and allopatric speciation. In sympatric speciation, a single species diverges to become two distinct species due to sexual preferences, a separation by a reproductive barrier, or polyploidy. Over time, a single area may have a population experience distruptive selection. For example, consider a plant with different colored flowers. A species of beetles that inhabit the flowers, but have preferences for certain colors will diverege if the preferences are different among the beetles (some prefer red while others prefer yellow). In allopatric speciation, a separation, a geographic barrier between a once united group may cause the species to diverge as well. For example, in a pool that dries up and creating smaller pools, the fish that were once together become separated geographically. Over time, the fish will exert a preference for their own kind if re-united. This too, is an example of speciation of a single species, now separated by preferences due to evolution.

Research is best done from a variety of databases, and the library is a reliable source which data bases are paid for. When using Google Scholar, beware of “relevance” searches which rely on the number of links associated with the data base. This could be outdated over time. Documents may be sorted by dates as well, but it does limit the number of articles and also will display the results by when they were added, not when they were written. Furthermore, certain databases will not allow Google to flag the articles and will prevent it from showing up in the searches. Scientific research is extremely lucrative among editors and peer reviewers in order to improve research. Predatory journals do exist and are not verified and may show up in Google Scholar.

Axolotls are amphibians, specifically neotenic salamanders that live their entire lives under water- for the most part. Occassionaly, they will undergo metamorphasis and grow land limbs, but even then, they will spend most of their time under water. They are known for their incredible regenerative adaptation. Limbs that are lost are grown back and make full recoveries without any scars. When a limb is cut off, the cells lose their identity and become pluripotent cells, stem cells that take on the part that was lost. The extent of this ability is so profound that they scientists have been able to transplant the head of one axolotl onto the back of another and have them survive for months. Unfortunately, in the wild, they are only found in one location and are under critcal pressures of pollution, and are endangered due to loss of habitat. Originally, they were numerous in Mexico and were revered by the Aztecs during their peak.

Certain species that defy expectations of sexual gender are important in helping biologists understand reproductive mechanisms. Not all species fit perfectly into the definitions of specific species concepts like the morphology or biological species concepts. The reproductive mechanisms for numerous species of lizards, fungi, and microbes differ drastically from mammalian mechanisms of reproduction. Certain species will reproduce sexually but do not fail to produce offspring even in the absence of the opposite sex. This is common in lizards that will lay eggs with no need for fertilization from the male counterpart. The viability of the offspring are high. Other traits that defy the biological species concepts include hybrids that are able to produce fertile and viable offspring with other hybrids but somehow, unable to cross with the parental species. These are instances in which the expectations from sexes and reproductive success are unable to fit perfectly into the human made concepts to understand nature.

Speciation is the evolutionary process by which new species arise. Although the definitions of what a species is does vary, the mechanisms by which these differences among species arise is consistent. Two types of speciation are sympatric and allopatric speciation. In sympatric speciation, a single species diverges to become two distinct species due to sexual preferences, a separation by a reproductive barrier, or polyploidy. Over time, a single area may have a population experience distruptive selection. For example, a group of beetles that breed within flowers of a plant, but if the plant has a mutation and produces a new colored flower, one that would attract certain beetles, the separation and preference causes the species to diverge. This is an example of pre-zygotic, behavioral isolation. In allopatric speciation, a separation, a geographic barrier between a once united group may cause the species to diverge. For example, in a pool that dries up and creating smaller pools, the fish that were once together are now separated geographically. Over time, the fish will exert a preference for their own kind if re-united. This too, is an example of speciation of a single species, now separated by preferences due to evolution.

Speciation is a concept created by humans to organize life, but nature exists as it is without need to be understood. The concept of a species can therefore, be defined in a variety of ways. A few common ways that species are understood by humans include the biological concept, the morphological, phylogenetic, and ecological concepts. The biological concept defines a species as a group of organisms that can produce fertile and viable offspring, but excludes asexual species, extinct species, and species that create viable and fertile offspring. The morphological concept defines species as having similar development and morphology (shape). Phylogenetic concept tracks the genetic evolutionary relationships between the species. The ecological species defines species by their niches. The different concepts help to understand species, but they are often imperfect and cannot include all life in the categories that humans have created.

A single carbon bonded to four groups has eight electrons, a full octet. If one of the groups attatched to the carbon is a leaving group, and is capable of removing an electron from the carbon along with itself, a carbo-cation is formed. This carbo-cation will have six electrons. However, when the ectrons are taken by the carbon from one of the groups, this creates a carbo-anion, which will still have eight electrons attatched to itself. If electrons in one bond of the groups is split between the carbon and the leaving group, a free radical is formed. Free radicals that left the carbon leave the carbon with seven electrons.

Sleep Theories

There are several theories on why animals must sleep. Some of these theories include the "repair and restoration theory," "evolutionary theory," and "information consolidation theory." The repair and restoration theory suggests that physiological processes are restored and revitalized when organisms sleep. This also ties into the other theories, which are likewise all interconnected. The evolutionary theory suggests that sleep is an adaptation. According to this theory, when food supply was short, in order to conserve energy, organisms developed the adaptation to sleep. The information consolidation theory, similar to the repair and restoration theory, suggests that sleep helps process information gathered from the day. It also helps with processing information during periods of being awake. However, these theories do not fully capture why it is necessary to sleep, and some biologists have made claims that sleep is one of evolution's biggest flaws.This is because sleeping organisms are more prone to attack while they are asleep.

An acid base extraction involves looking at a mixture and separating the two solvents within to extract pure compounds.The compounds, when mixed with two different solvents of different densities will separate into two layers. After the compounds are mixed and layers are formed in test tubes, the two phases are separated via pipet. Once the solvents are evvaporated, the separated, we get a yield of the solid compounds. Once the solids are aquired, purification may be done by recrystalization to remove any impurities.