, English naturalist and geologist
Reprinted in Charles Darwin: His Life Told in an Autobiographical Chapter, and in a Selected Series of His Published Letters, edited by Francis Darwin. London: John Murray, Albemarle Street. 1892.
Evolution is an explanation for a seemingly inexplicable topic: life. Life exists throughout the world in the smallest bacteria, in the largest whale, and anything in between. The variance in the forms of life and the myriad of diversity has led many men to ask how this has come to be. The answer is evolution. NASA's working definition of life is a "self-sustaining chemical system capable of undergoing Darwinian evolution."
Evolution is any change in the allele frequencies of inherited traits in a population that occurs from one generation to the next.
One of the major pitfalls people have when considering evolution is that they don't recognize one of they key components to understanding this concept: evolution is gradual and is looked at through generations, not individuals, and within populations of the same species.
Defining Life. Steven A. Benner. Astrobiology. 2010 December; 10(10): 1021–1030. doi: 10.1089/ast.2010.0524
Pre-Darwinian Evolutionary Thought:
The philosophy of evolution
is something that is a rather controversial issue, here is a link to a stanford article explaining the philosophy of evolution throughout history, such as the ideas of plato, aristotle, kant, descarte and other prominent philosophers.
is a theory proposed by Jean-Baptiste Lamarck describing the heritability of acquired traits that was later abandoned after the growing evidence of theory of evolution as described by Charles Darwin and his successors. Lamarckism was founded on the idea that organisms pass on traits acquired during their lifetime based on use and disuse. Here's
a helpful video on Lamarckism.
Darwin was not the only one to coin "Evolution"
While people have come to know Charles Darwin as the Father of Evolution, he was not the inventor of the concept of evolution. Others before him had similar thoughts on the process of evolutionary change. However, it was Darwin that proposed one of the known mechanisms by which this change occurs. This was his theory of natural selection.
- The Greeks had a philosophical notion of descent with modification starting from around 500 B.C with Heraclitus continuing through the work of his successor Empedocles roughly around the early 400 B.Cs.
- In his book Critique of Practical Reason (1788), Immanuel Kant speculates that animals with physical similarities may have come from a single ancestral source.
- Erasmus Darwin, Charles Darwin's grandfather, wrote of evolution in his poems, suggesting that "all warm-blooded animals have arisen from one living filament". He also wrote an idea similar to survival of the fittest in his work Zoönomia in which he says "the strongest and most active animal should propagate the species, which should thence become improved".
Darwin's Theory: Taken from the end of On The Origin of Species
"It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various
insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner, have all been produced by laws acting around us. These laws, taken in the largest sense, being Growth with Reproduction; inheritance which is almost implied by reproduction; Variability from the indirect and direct action of the external conditions of life, and from use and disuse; a Ratio of Increase so high as to lead to a Struggle for Life, and as a consequence to Natural Selection, entailing Divergence of Character and the Extinction of less-improved forms. Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows. There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved."
This is a figure of that depicts the evolution of the finches that Darwin studied.
The Earliest Forms of Evolution
- Richard Dawkins, in his book The Selfish Gene, describes the earliest form of evolution as the stability and continuation of the first and randomly created genetic molecules. As these early proto-DNA molecules interacted with each other and the molecules around them in an aqueous environment, some, by random chance, started to replicate. This process increased the population size as well as the stability of that one set of proto-DNA, otherwise known as the first gene. This process has continued into life today.
- Dawkins also describes the organisms and cells all time as nothing more than the vehicle for the stability of each gene in our genome. Evolution is a process of killing, duplicating, keeping, and altering certain genes via the effect of natural selection on the vehicle of the gene's existence, or the cells and organisms in which the genes abide. This idea eludes to the title of the book, The Selfish Gene.
Misconceptions about Evolution:
is a source from Berkeley that list and corrects many common misconceptions about evolution.
to see more details about the common misconceptions about evolution.
One of the biggest misconceptions people have is the idea that humans evolved from chimpanzees. In actuality, no modern-day species evolved from any other modern-day species. Evolution is not linear; rather, speciation occurs in branches. Humans and chimpanzees share a relatively recent common ancestor, and are thus very closely related. However we did not evolve from chimps.
Now that we know what evolution is, check out
how evolution is often misrepresented in the media. "I think that we’ve stopped evolving. Because if natural selection, as proposed by Darwin, is the main mechanism of evolution – there may be other things, but it does look as though that’s the case – then we’ve stopped natural selection.” For someone who has no background in evolutionary biology, articles and quotes like these can be incredibly misleading.
At the end of the line, evolution may escape the general definition we learn in class. People are now moving forward in a field called biomimicry, where people begin to use evolution as a tool to further our own evolution and learning. Here is an introduction
to the subject, in which Janine Benyus outlines several incredible examples of where their studies are moving.
Here is a video
that explains myths and misconceptions of evolution.
Here are some Genetics Definitions to know when talking/ reading about evolution.
Here are common questions that evolutionary biologist ask: Understanding Evolution. 2013. University of California Museum of Paleneotology. 13 October 2013.
1. Does evolution tend to proceed slowly and steadily or in quick jumps?
2. Why are some clades very diverse and some unusually sparse?
3. How does evolution produce new and complex features?
4. Are there trends in evolution, and if so, what processes generate them?
Something to Ponder
How much effect does overfishing have on the size of fish? Where do these giants come from? Why?
Opposition to EvolutionFish Wars
: Evolution vs. Creation
Miscellaneous Links about Evolution
- Seems we have some evolutionists in Athens! Snapped this pic in morning traffic. Pretty neat!
Click for full-size image