What Is Natural Selection In Biology Quizlet?
Darwin's Natural Selection
Natural selection is the difference in survival and reproduction of individuals. The heritable traits of a population change over time. Charles Darwin preferred the term "natural selection", which he believed was intentional, over the more common term " artificial selection". By the life cycle stage where it acts, by the unit of selection, or by the resource being competed for, selection can be classified in a number of different ways.
Evolutionary history of fossil evidence
The members of the species with the most desirable characteristics are able to produce offspring. If a species is unable to adapt, it is at risk of extinction. Evolution can take many thousands of years to happen. Fossil evidence has been used by scientists to look at how organisms have evolved over millions of years.
Evolution of the Southern California Field Mudwort Plant
Over the next generations, evolution is the change in the characteristics of an organisms. It is sometimes summarized as a descent. Natural selection is one of the mechanisms that drives evolution.
The fossil record shows that species change over time and new species are formed. There was no explanation of how changes could be made. Darwin relied on his notes, observations and interpretation of the writings of Thomas Robert Malthus for his conclusions.
Malthus was an English scholar who wrote about theory that population growth will always outrun the food supply. Competition for a limited supply of food will cause many individuals to die. Natural selection is strong because of the rapid multiplication of the population ofbacteria.
They usually grow until they reach a constraint such as lack of food, space or other resources. The best suited of thebacteria will survive while the rest will die off. Natural selection in the development of antibiotic resistance is an example.
All other antibiotics will not work if the individual is treated with antibiotics. The proliferation of antibiotic-resistantbacteria is a major problem. Natural selection in plants is an example of this.
Disruptive selection in a population
One extreme of the trait distribution experiences selection against it. The population's trait distribution is shifted to the other extreme. The mean of the population graph changes when selection is made.
The selection pressure against short necks was based on the fact that people with short necks couldn't reach as many leaves to eat. The distribution of neck length shifted to favor long-necked people. In disruptive selection, selection pressures can affect individuals in the middle of the distribution.
The result is a two-peaked curve in which the two extremes of the curve create their own smaller curves. Imagine a plant that is pollinated by three different people, one that likes short plants, another that likes medium plants and a third that likes the tallest plants. If the pollinator preferred plants of medium height disappeared from the area, the population would prefer short and tall plants.