Dr. Moalem discusses the "adaptive value" of the organisms; in Chapter 2 page 45, he discusses the evidence that in a extreme cold weather, mice are resistant to insulin thus the blood sugar level
increases. This can help mice to survive in cold weather since the freezing point of water will be depressed when great amount of sugar is dissolved into water. In page 57 chapter 3, Dr. Moalem also discusses the skin colours that defend folic acid that exists in skin. The another example is sickle cell disease; the deformation of red blood cells can help prevent protists to inhabit inside red blood cells and this can prevent Malaria.
However, as Dr. Moalem points out multiple times in the book, most of adaptive values have its own weaknesses. In the case of insulin-resistant rats (or insulin-resistant humans) would suffer diabete due to high blood glucose level. People with darker skin have less ability to produce vitamin D, hitch is essential to our health. Lastly, people with sickle red blood cells suffer from horrible anemia. In many cases, the adaptive values that is observed in real world do not have clear benefits as tusk-less elephants or guppies with darker colours do. However, according to the theory of natural selections that Darwin suggested, all organisms are under selection pressures so that they all have to adapt to the environment. This is, I believe, extensively discussed extensively throughout the AP Biology course, and it is one of the Big Idea of course (Big Idea 1 about evolution). From this information, how would you define what "adaptive value" is? You can reflect upon the evolution unit or the recent units such as basic metabolic processes (photosynthesis and cellular respiration) to refer the examples of how these processes can help organisms.
— Makoto Seita, e-mail: mseita3@students.d125.org
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ReplyDeleteAdaptive value is an ability for a trait to help an organism cope with the environment through natural selection and Darwin's principles of evolution. Adaptive value very much affects the behavior of organisms, because organisms are adapting to a larger variety of environmental circumstances. This is believed to be imprinting, the behavior, both innate and learned, that organisms may use. From previous chapters like ecology and relating to Big Idea 1, imprinting is learned at an early age, things such as baby ducks staying close to their mothers for feeding. Adaptive value can be very beneficial for organisms. For example, in an article by ScienceDaily, it describes how male chimpanzees can now form coalitions with one another in order to direct aggression to other chimpanzees. This trait of forming relationships and communicating like this has a lot of adaptive value for the chimpanzees because it shows "a more complete understanding of social intelligence and the evolution of co-operation."(http://www.sciencedaily.com/releases/2012/12/121203112810.htm). In this case and many others, adaptive value is the value of a trait that has developed over time that has been made to be very beneficial for the organism.
ReplyDeleteMentioning evolution into the aspect of adaptive value, we have learned in AP Biology, in the evolution unit, that through lots and lots of time, and through environmental factors, organisms have the ability to evolve and adapt to their environments. On page 53, Dr. Moalem describes how darker colored skin may be an adaptation for "the loss of folic acid" and "to protect against sunburn". However, later, he also describes how this once beneficial adaptation also prevents for the creation of Vitamin D. If adaptive value is the added ability to cope with the environment through adaptation and selection, then a once beneficial adaptation can be detrimental later on. Adaptive traits can have high beneficial value because of the natural selection flowchart we discussed previously in the year. In the case of darker skinned people, that itself is the variation, and it is a favorable trait that is selected for because of its ability to protect against sunburn or loss of folic acid. However, although it was favorable at one point in the evolutionary process, it became an unfavorable variation for its inability to produce Vitamin D. In these cases, it is shown that these adaptive traits have a good or bad adaptive value, and also that these traits may not have the same adaptive value 1,000 years from now.
The adaptive value of many traits should help organisms in surviving and reproducing in a certain environment. In both dark skinned people and in cold response in mice, Dr. Moalem describes how these traits are beneficial to the organism, therefore having more adaptive value to the organism. It is "adaptive" because organisms must first understand their environment and then through the evolutionary process, can develop traits to help cope with these pressures.