EVOLUTION is defined as change over time.
ORGANIC EVOLUTION is the genetic (and phenotypic) change of living organisms over time.
However, his experiments were discounted because...
2. critics said that boiling the broth might have somehow destroyed some "vital principle" in the broth and/or air, making it unfit for spontaneous generation.
The stage was set for the Darwininan Revolution!
His dad, a famous physician, thought that no good life could await a naturalist, and so sent young Charles, at the age of 16, off to the University of Edinburgh medical school. HATED IT.
Dropped out after making mediocre grades
Enrolled at Christ College at Cambridge University with plans to become a clergyman. (This isn't as weird as it sounds, since most scientists of his day were members of the clergy!)
He fell in with the biologists and became the star pupil of Rev John Henslow, Professor of Botany.
1831 - with the help of Darwin's uncle, Henslow convince both Captain Robert Fitzroy of H.M. S. Beagle and Darwin's dad to let Charles go on the 5-year Beagle voyage as "unpaid gentleman scholar and naturalist."
So at the age of 22, Darwin set sail. While the Beagle's crew mapped South American coastlines, he went ashore and collected every living things he could lay his hands on.
1836 - Darwin returned to England, settled down and got married and wrote up all his work.
1858 - Darwin was nearly scooped by Alfred Wallace, a young British scientist studying plants in Malaysia. (Alarmed at Darwin's failure to publish his ideas, his friend Charles Lyell had warned him about this possibility!)
Lyell and some colleagues presented both Wallace's and Darwin's work at the meetings of the Linnaean Society of London on July 1, 1858. Wallace's and Darwin's ideas were identical, but Darwin's had been written first, and with much more completeness than Wallace's. Today, Darwin is given credit as the Father of the Theory of Evolution by means of Natural Selection.
Darwin made some profound observations, from which he inferred some brilliant conclusions...
2. Those offspring are variable in appearance and function, and some of those variations are heritable. (The tenet of HERITABLE VARIABILITY)
3. Environmental resources are limited, and those varied offspring must compete for their share. (The tenet of COMPETITION)
4. Survival and reproduction of the varied offspring is not random. Those individuals whose inherited characteristics make them better able to compete for resources will live longer and leave more offspring than those not as able to compete for those limited resources. (The tenet of DIFFERENTIAL REPRODUCTION)
The popular phrase "survival of the fittest" that's often ascribed to Darwin was a phrase originally used by Herbert Spencer, (27 April 1820 - 8 December 1903) an English philosopher, in his 1851 work Social Statics. (The phrase was later used by Social Darwinists, but that's another story.) The phrase "survival of the fittest", when applied in the colloquial sense, is not truly meaningful when applied to Darwin's theory.
The fittest organisms are those that leave the most genes to the next generation, nothing more and nothing less. Survival doesn't always ensure fitness, and fitness doesn't always ensure survival.
Any trait exhibited by an organism may be
A SPECIES is a group of similar organisms that can mate to produce fertile, viable offspring. Different species are, by definition, REPRODUCTIVELY ISOLATED from one another.
To understand a little more about how evolution works, let's refer to this GENETICS PRIMER.
The Natural Sciences (Physics, Chemistry, Biology, Geology, etc.) are all governed by the necessity of their adherents to utilize
...to add to the knowledge of their field.
The Scientific Method is a precise set of rules followed by researchers/investigators in the natural sciences.
The Scientific Method consists of the following steps...
"The process known as the Scientific Method outlines a series of steps for answering questions, but few scientists adhere rigidly to this prescription. Science is a less structured process than most people realize. Like other intellectual activities, the best science is a process of minds that are creative, intuitive, imaginitive, and social. Perhaps science is distinguished by its conviction that natural phenomena ,m including the processes of life, have natural causes--and by its obsession with evidence. Scientists are generally skeptics." (from Biology by Neil A. Campbell
So don't confuse The Scientific Method with Science, in general. And also note that if something is outside the realm of scientific testability, the wise scientists will not presume that it is not true, or that it does not exist. It is simply outside the realm of Science, and may not be answerable with the Scientific Method.
A common theme in scientific endeavors is the use of HYPOTHETICO-DEDUCTIVE reasoning: The formulation of hypotheses (a tentative answer to a question) and the execution of experiments from which one may deduce a general answer to the hypothesis.
Important aspects of hypotheses...
Let's try it ourselves and see! Think of a question in genetics, and we'll run it through the process to see how it goes.
You'll often hear Darwinism dismissed as "only a theory." But this tactic has two major flaws:
The only part of Darwinian thought that's "theoretical" is that evolution has occurred by means of natural selection. Scientists do not question that evolution has occurred (all physical evidence clearly says that it has), but only how it has occurred. And Darwin's hypothesis was that it has occurred by means of NATURAL SELECTION.
Also remember that in science, the term THEORY has a very precise meaning that is quite different from the colloquial use of the term.
A THEORY is an hypothesis whose predictions have stood up to thorough and rigorous testing with experiments and observations. Such has been the case with Darwin's hypothesis, and so it has been elevated to a THEORY.
Still, neither a hypothesis nor a theory can be "proven" with the scientific method, and a good scientist refuses to let even the most powerful theory become DOGMA (something held as an established, unquestioned opinion). New evidence should always be examined with an open mind, as even a powerful theory is always subject to modification and revision.
(Note: A theory that is ultimately proven to hold true in all cases becomes a LAW. There are very few laws in natural science, most of them in Physics, such as the Laws of Thermodynamics.)