What features of biological oscillators would provide an evolutionary advantage?
The Systems Biology of COVID-19 and the SARS-CoV-2 virus. The class will build a foundation that includes the emergence of complexity, simple biological subsystems, their reductionist and equivalent toy and organ-chip models, and the measurements required to specify model architecture and parameters. Applications to biology, physiology, medicine, chemical and biological defense, pharmacology, drug discovery, and toxicology. UGrad: PHYS 240 01 and BME 290B; Grad: PHYS 326 and BME 395C.
SysBio13 Pop Quiz - Why Oscillators?
ReplyDelete1) Oscillations in a biological system are present to keep the living thing in some sort of steady state. This state is a small range at which the system is happy. So, the oscillator keeps the system between the high and low of this state while shifting back and forth toward the “homeostatic” point.
2) If there was only a strict homeostatic point rather than a range, it would be very hard in such a dynamic and interconnected system to keep one at this healthy state. If the system was knocked from this specific point, even just a little, the body would assume something was wrong and would have to correct for the variation in some way. Thus, it would constantly be fighting, too hard, to be healthy. Without a range in which the system oscillates, the “alarm” systems and mechanisms for recovering from irregularity (no matter how small) would constantly be triggered. With the oscillations, the body can still be stable without being on the brink of distress at any moment.
Why do biological systems oscillate?
ReplyDelete1. In extremely simplistic terms biological oscillators keep organisms alive. Oscillators provide the ability of a organism to adapt to change such as changes in temperature. By oscillating over a range of variables an organism is able to meet the stress of the environment. If temperature for example is a set degree then the organism would not need to oscillate but since temperature changes organisms also need to change with the temperature. This oscillation keeps the organism homeostatic where it is not really static rather within a range or steady state.
2. Oscillators provide an evolutionary advantage by providing an organism with the ability to adapt to a range of conditions. This oscillation could by changes in viscosity and pressure in blood flow or temperature changes, or on a large scale the availability of water. Without the ability to oscillate the organism would be static and fail to adapt to the changes in the environment. Hence if an organism is eats plants and those plants live at a certain elevation then the organism that eats the plants need to be able to travel or move to that elevation and adjust to all of the changes associated otherwise it will die.
SysBio13 Pop Quiz - Why Oscillators?
ReplyDelete1) It could serve as a biological timer to help keep things synchronized. In the heart, pacemaker cells are pulse coupled oscillators which spontaneously synchronize.
2) It is one way for physiological quantities to vary over an acceptable range, rather than settling down to a particular value (e.g. constant heart rate isn't healthy). This could be helpful for an organism to more quickly respond to a sudden change in external conditions.
Frank "Edad" Block, Jr.
ReplyDelete1) None of biology is in a steady state. Oscillators allow essential activities such as hearts that beat in rhythm, peristalsis in intestines, circadian rhythm, sleep, etc.
2) The heart allows circulation in larger, complex animals, and oscillators are necessary for heart beats. Peristalsis is needed for intestines for efficient food processing. Sleep decreases daily energy need.
1) Biological systems oscillate so that organisms can respond to changes in the internal and external environment and effectively maintain themselves (stay alive).
ReplyDelete2) A biological oscillator that was able to adapt to changes in an organism's environment and keep the organism alive would have an evolutionary advantage over an oscillator that wasn't adaptable.
1. I think one of the most important characteristics of oscillators is that they serve as natural timers. Not only do you need the correct elements (signalling molecules, proteins, RNA, etc) in proper concentrations in the correct location, but you also need to control the timing of when these molecules are present. For example, cell division markers or apoptosis markers.
ReplyDelete2. It gives an evolutionary advantage by allowing for variation in an organism without catastrophic results. It is unrealistic for an organism to maintain perfect levels of each element at every single moment. Not only is this unrealistic, it's just not amenable for life. There is a constant change of input's that an organism experiences.
1. Processes are constantly in a dynamic environment so oscillators provide robustness from internal and external perturbations. While concentrations and enzyme activity are in flux, they’re within a more rigid set of bounds and the status quo is maintained.
ReplyDelete2. Mechanisms can only respond to signals they recognize, and oscillators provide a ‘stable flux’ for systems which constantly respond to time/spatially delayed internal perturbations that are more adept at handling external changes than systems with a singular stable point.
1. Oscillators allow conditions from the past to affect conditions in the future. As the paper says: “‘Memory’ might be a simple consequence of a long negative-feedback loop, but more likely it stems from positive-feedback loops in the biochemical reaction mechanism. When positive feedback creates two alternative stable steady states in the reaction dynamics, the system can ‘remember’ its recent history and hereby overshoot and undershoot the homeostatic tendencies of the negative-feedback loop. “
ReplyDelete2. Evolutionary advantage: Could it be possible that cells start out similar to a stretched spring? There is a high-level (made of smaller systems) system whose amplitude slowly fades, and below a certain threshold becomes ineffective? This would be necessary for programed cell death because a steady-state cell wouldn’t know when to die, and thus would outcompete its own offspring, and thus wouldn’t “evolve” very quickly. Frank’s reasons are necessary now, but perhaps programmed cell death was an important determinant in life’s early evolution.
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