what is the mean of the sentence "evolution is a stochastic process , it is not a directed process in the sense of determinism" ??????
Although I am a student of Math/Engineering. I am an advocate of Evolution. I believe that the planet Earth and all species including our existence are result of chance events, or accidents. It has not been designed for any purpose. The Universe and life have no purpose at all.
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Stochastic and Deterministic are systems in Mathematics / Physics.
Stochastic means 'random' or 'pertaining to chance'. In a stochastic process there is some 'indeterminacy' or 'randomness': even if the initial condition (or starting point) is known, there are several (often infinitely many) directions in which the process may evolve. For a system to be stochastic, one or more parts of the system has randomness associated with it. A stochastic system does not always produce the same output for a given input.
Deterministic means 'no randomness' is involved in the development of future states of the system. A deterministic model will thus always produce the same output from a given starting condition or initial state. A deterministic process proceeds in a fixed predictable fashion without random fluctuations.
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Now coming to the topic of evolution. By stochastic it means evolution is 'by accident' . We can't predict the outcome of evolution. Though it should not be thought that all of evolution is entirely due to chance or accident.
1) Mutations are random.
2). Genetic Drift is random / stochastic.
3). Natural selection is deterministic(non-random). However there is a debate as to whether natural selection is stochastic or deterministic.
The end result is evolution is not a predictable process.
There is a good deal of the past history of life on Earth was the product of chance events, or accidents, that could not have been predicted. These many random events that took place in the past had a profound influence on the outcome of evolution. The individual events that occur are often haphazard and unpredictable. The end result—in this case a modern species—is unpredictable because at each step there were many different paths that could have been followed. This is evolution by accident or stochastic evolution.