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Lecture 1: -Looking at a comparison between an animal that lives in low temperature and an animal that lives in high temperatures. Low temp would have a lowrate function, and high temp would have a high rate function. (so graph would be a straight line). The reason for that is kinetics, kinetics are temperature sensitive. You can make an animal live at a different temperature, and its rate function would just shift down the graph. If you look at rate function (lets say metabolic rate) of goldfish at 25 degrees, and look at the one that’s adapted to 10 degrees, and if you look at the Antarctic fish (-1.86 degrees water), they all follow the horizontal line which means organisms can adjust their metabolic rate within a wide range of temperatures so basically its always the same. This is called ratecompensation. They have an ability to adjust; they can do that do that on a seasonal basis, and an on evolutionary basis. Paper that Hochachka/Somero wrote in 1968 called Adaptation of Enzymes to Temperature and proposed a mechanism to explain this. They suggested that temperature (besides having kinetic effect) also could modify activities, meaning it would directly modify the enzyme and therefore the activity. -Hard to define adaptation, because its overused and it occurs at all biological levels. Have an idea of what adaptation is (exam). First definition: basically increasing fitness in a certain environment. Second: there are certain things that are important for an organism in the environment and if they don’t respond to them they die. -Key ideas are listed in slides. But there are problems with these definitions. What is an environment? Where the organism lives or the ecological niche which is controlled by biotic and abiotic factors. Adaptation has to be considered as optimization process (can solve problems but only to a certain extent) and there is no such thing as perfection. It is a continuous process because the environment is constantly changing. If there is a change in the amount of oxygen, for example a reduced amount in water, the fish increases amount of water flow across its gills or it could start using anaerobic metabolism. (different solution for same problem). 3 determinants to adaptation: first is genome specified which means the genome of that organism really determines thelimits of its adaptational ability (certain things organisms can do that others cant because they don’t have those genes). The second thins is its environmentally induced, so environment is responsible for bringing adaptation to surface. Developmentally defined means that in certain stages of development you are more likely to adapt. -Two components of natural selection. One of them is that organisms very and the variation is inherited in part by offspring. The second component
is that organisms can produce more offspring than can possible survive