Twinning is Winning

     Darwin's postulates about natural selection state that 1: there is variability of individuals within a species, 2: some of these variabilities are heritable, and 3: the individuals with the favorable variations reproduce the most. With this in mind thinking about mutation, I think mutation rates do evolve. Each individual in a population has a different genome, and out of each one of those could arise a mutation, possibly several. Some of these mutations are heritable, and if it is a favored mutation, will get passed on to future generations.       I think many mutations are influenced by the individual's environment, which can be beneficial to some populations. Take for example a population that moves around to different environments frequently. If a population is very mobile, high mutation rates increase beneficial adaptations to help the population better survive in each new environment. In this case, high mutation rates would be adaptive....

To me, fitness is a way to describe an animal's ability to survive and reproduce in an environment. How well it can obtain food, avoid predation, and contribute to its population's gene pool via reproduction. To measure fitness in a natural population, you would have to take into account the main ideas listed above. Otherwise, you would just be looking at one aspect of fitness. For example, let's look at a white-tailed deer. You would have to measure what its nutrient intake should be, and estimate if the animal is receiving adequate amounts (it would be next to impossible to measure how much a wild animal eats, since you cannot weigh everything it will eat outside of captivity). If it is a dry summer, there might not be as much vegetation or water for the deer, and it can impact the fitness. You would also have to see how well it seems to avoid predation; animals with fur color mutations have a tougher time of doing this. Deer tend to be able to camouflage themselves pret...

My favorite prediction of Darwin's descent with modification is microevolution- species changing through time. An example that embodies this idea is the migration time in a population of pink salmon. Scientists have discovered this population of salmon have been migrating earlier each year, and they want to find out if a) it is a genetic change and b) if it is due to climate change. They do discover that there has been a phenotypic decrease of the late-migrating fish, which would show microevolution has occurred. They also believe part of the push towards this new migration time does  have to do with climate change. In the past, this type of salmon chose when to migrate based on when they could avoid high stream temperatures. With global warming, the high stream temps are coming earlier than they normally have in the past 40 years, which could be an essential factor in this example of microevolution. Resources:       https://royalsocietypublishing.org/doi/1...