For example, my favorite organism is the tardigrade because evolution has selected for it the ability to live in a dehydrated state for many years (anhydrobiosis) and then being able to transition into an active state upon receiving water. Tardigrades are really interesting because they can survive 1000 times the radiation that a human can withstand. These traits make it a polyextremophile that can survive and reproduce in almost any condition.
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My favorite example of evolution is the Antarctic icefish. The Antarctic icefish has adapted to be able to survive the freezing temperatures of the Antarctic Circle. Unlike other species that live in the area, the Antarctic icefish has developed a hemoglobin-less blood that acts as antifreeze. Without such adaptations, the icefish would never survive because the water would freeze in the blood vessels, and since water expands when frozen, the vessels would burst and the fish would die. The mutations that caused the development of the icefish made the fish more likely to survive, and thus, those genes were passed to future generations.
ReplyDeleteMy favorite evolutionarily significant organism is Homo sapiens, commonly known as humans. Humans have the unique advantage of having evolved an extremely complex cranium that is proportionally very large, which is capable of using tools and technologies. Humans are some of the few organisms that are able to physically manipulate their environment in order to better maintain homeostasis.
ReplyDeleteOne example of this is the creation of fire. Humans are the only known organisms to create fire, and they use fire to increase the temperature in the environment. By increasing the temperature in a cold environment, humans are able to spend less energy on creating heat to maintain thermal homeostasis. The saved energy is then stored or used for other, more pressing biological processes, which increases chances for survival and reproduction.
Humans are also notable for their extremely social nature, which is a characteristic shared by most higher order primates. Humans are especially adept at communication, having developed complex verbal, written, and gestural mechanics in order to communicate with each other. Humans also have developed complex social structures such families and communities. These structures help humans provide support to their offspring in an efficient manner. This is a selective advantage because if an organism’s offspring survives to reproduce, then the genetic information of the original parent is also passed on to the offspring’s offspring. The development of these social structures with human populations has led to a significant selective advantage for the species.
My favorite example of evolution is... the Tardigrade, or more commonly known as the water bear. This animal is the essence of the incredible ability to adapt, survive, and one day (whenever that day comes) to reproduce. They can survive temperature ranges between -272 degrees celcius (one degree above absolut zero), to 151 degrees celcius. They can withstand the extremely low pressure of a vacuum or extremely high pressure (1200 times the earths atmospheric pressure). Not only that they can lose about 99% of their bodily water and survive over a decade without a single drop of the stuff. On top of that, they can even surive 100 times the radiation of a human. In my eyes, they are the ultimate evolutionary organisms. Recent studies shown they can even survive ten days in out space! OUTER SPACE!
ReplyDeleteOh no!... Sam posted the same exact thing. Well I'll keep this and simply say I agree with Sam :(... ahh my second favorite animal is the shark because it has a sixth sense in which it can detect electric fields. Thats a prime example of how the genetic code is constantly expanding and the ability of what an organism can do is "updating" daily. After all, if we humans could sense electric fields or spit poison, those would be considered "science-fiction" super powers.
My favorite evolutionarily significant organism is the Coelacanth. The coelacanth seems to have maintained its form despite evolution, as it was similar to the fish that was “believed to be extinct since the end of the Cretaceous period 65 million years ago” (119). Because of the coelacanth is considered a “living fossil” (119), it contains the essential fossil genes that have been kept fairly constant by natural selection. The fossil genes are genes found in a wide variety of organisms and have been selected for by natural selection because of their integral functions to the organism. The coelacanth have survived to this day because of these fossil genes.
ReplyDeleteEven though the coelacanth are largely similar to their ancestors 65 million years ago, they have developed adaptations to their environment. For example, the coelacanth have no MWS/LWS opsin gene, and their SWS gene is disrupted with mutations. As we have learned, the mutations can cause a premature termination or change amino acids that need to be coded for. The protein created would be non-functional because of the changed genetic text. The fact that the coelacanth have a decayed SWS showed that their ancestors once had a functional opsin, and the coelcanth have lost the opsin the gene coded for due to the relaxation of natural selection. The relaxation of natural selection has allowed these opsin genes to fall into decay because the genes are not used in the habitat of the coelacanth. The coelacanth live in deep waters where light does not permeate the water. Because there is no light in the fishes’ habitat, the coelacanth would not be able to detect color even if they had the opsin genes. The decay of the MWS/LWS opsin relates to the theme of interaction with the environment, as the theme deals with how an organism will change when faced with different environmental pressures. The coelacanth are a perfect example of the blending of the old and the new: they have maintained the genes of their ancestors while developing new adaptations to their environement.
My favorite evolutionary significant organism is...a gibbon! Gibbons have very long arms and move through the trees in an acrobatic maneuver. Also, gibbons are monogamous (meaning that each gibbon only has one mate at a time). Gibbons are more commonly known for their extremely loud voices. Known as the "songbirds of the rainforest", a gibbon's voice can travel up to two miles. This long range allows the gibbon to attract mates from a wider range.
ReplyDelete(http://www.gibboncenter.org/about_gibbons.htm)
Gibbons, just like all other anthropoid primates (monkeys, apes, humans), the gibbon has an opposable thumb (meaning that the gibbons "can touch the ventral surface of the tip of all four fingers with the ventral surface of the thumb of the same hand" (Campbell 707)). Gibbons, according to the phylogenetic tree of primates (fig 34.35 pg. 708 of Campbell), orinigated about 15 million years ago. The branch of the fork that differentiated into gibbons is related to the other side of the fork containing orangutans, gorillas, chimpanzees, and humans. This means, that besides human's closest relative (chimpanzee), gibbons are pretty close. Maybe humans obtained our ability to produce a loud sound like a scream from the gibbon. In fact, "Structural and behavioral similarities suggest that, of all vocalizations produced by nonhuman primates, loud calls of Old World monkeys and apes are the most likely candidates for models of a precursor of human singing and, thus, human music" (http://www.umweb.org/zm/music_and_primates.htm). And just like in humans (who like Aaron said humans have a very developed social nature), the gibbons use their loud voices to communicate sources of food, shelter, water, or danger, claim territory, call for a mate by pronouncing location, or intimidation -- structure function theme :).
My favorite evolutionary significant animal is the platypus. The platypus is very peculiar in the fact that is a semi-aquatic mammal that lays eggs. In addition, they are venomous and are often said to be duck billed and beaver tailed. Platypuses are part of the monotremes species. This species is the product of an early branching of the mammal tree. This opposed the idea that they were the product of a later branching between marsupial and placental groups. The far back branching means that platypuses have been on Earth for millions of years. Platypuses are typically shy creatures, but they also have the ability to kill dogs or even humans with their venom.
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