Natural Selection - Chapter 4 in the Origin of Species

So far in our tour of the Origin we have seen that pre-Darwinian scientists defined species as distinct entities created by God, and varieties as deviations from the species-type, such deviations occurring due to natural means.  Darwin, in part by observing the human-caused production of domestic organisms argued that varieties evolve within a species, and as they become more distinct they in turn become new species.  There is, therefore, nothing directly divine about the production of species (although God could still be operating behind the scenes, directing the evolution of species).  In chapter three, Darwin argued that organisms produce more offspring than can possibly survive.  Through some mechanism unknown to Darwin, these offspring differ from one another by a small degree; those individuals that have beneficial variations will outcompete those that do not, and will be more likely to survive and pass on their traits to their offspring.  This is the foundation of natural selection.

Struggle for Existence - Chapter 3 in the Origin of Species

Locust swarms involve intense competition for resources

At this point in our tour of Darwin’s Origin, Darwin has questioned the 19^th-century view of species as distinct entities created by God, and varieties as deviations from the species-type.  Instead, Darwin has presented compelling evidence, in large part through domestic organisms, that varieties and species are not different in kind, but only in degree.  That is, varieties, when they become especially well-marked, are identified as species.  A species evolves into different varieties; those varieties, in turn, may evolve into new species.

Darwin has also argued that there is a considerable amount of individual-level variation that exists in wild populations, and it is this variation that is the fuel for what he calls ‘natural selection’, a metaphorical phrase that he took from the phrase ‘artificial selection’.  Artificial selection occurs when humans look at a population and choose the individuals that have the best features for breeding.  Natural selection, although there is no conscious choice occurring, is the equivalent process that occurs in the wild.  Survival of the fittest.

In chapter three, Darwin sets the scene for his next chapter on natural selection.  Here he argues that waste and death is the hallmark of nature and is essential for speciation, rather than direct miraculous intervention from a beneficent God.  Babies die, and they die in large quantities.  This is an essential truth, if we wish to understand evolution. 

Variation under Nature - Chapter 2 in the Origin of Species

The giraffe species is divided into several populations, each exhibiting a region-specific colouration pattern on the hide.  These have become identifiers for dividing giraffes into distinct subspecies.

In the first chapter of the Origin of Species, Darwin looked to domestic animals and concluded that the varieties of domestic breeds were created by man by selecting individuals with slight variants and accumulating these changes over numerous generations.  He referred to this as artificial selection.  In chapter two he begins to show how artificial selection can inform us of how species are formed, through the more powerful ‘natural’ selection.

Variation under Domestication

This semester I am taking a course on Darwin’s first edition of On the Origin of Species.  I thought that I would post chapter summaries of the Origin as I read it, to help keep the material straight in my mind and hopefully introduce you to one of the most important texts of the past 150 years.  If you are a creationist, perhaps you will find less in this book to fear than you had thought; if you are a scientist, you might be surprised by how prescient Darwin was in many ways.  If you are neither, you will still be impressed with the power of Darwin’s arguments.  If you would like, you can follow along by reading the Origin with me – the first edition is free online at http://embryology.med.unsw.edu.au/pdf/Origin_of_Species.pdf. 

I will be skipping over the opening quotes (read my thoughts on them here) and the introduction, and will dive right into the meat of the thing.  This one's a long one...it should be shorter in the future!

The Big Questions of Evolutionary Biology - A Guide to 'Genetics and the Origin of Species'

Perhaps you don't believe in evolution.  Rob Bell, in Love Wins, asks people who say they don't believe in God, 'Which God?'  When they describe their understanding of the Christian God, Bell often discovers that he doesn't believe in that God either.  So if you don't believe in evolution, 'Which evolution?'  What is your understanding of evolution?  Because odds are, if your knowledge comes from Creationists, it is going to be filled with misunderstandings.  The best way to understand evolution is to delve into the writings of evolutionary researchers.  This is exactly what we will be doing over the next few weeks, as we explore Theodosius Dobzhansky's 1937 evolutionary classic, Genetics and the Origin of Species.  I will try to limit the scientific words that I use (or at least define the difficult ones), but I make no apologies.  If you want to know if evolution is true, you're going to need to learn some jargon.  Thankfully, Google dictionary exists to help us out!  If you're an evolutionist, you may also be surprised to read what evolutionary biology was like in the 1930s, and it may challenge some of your own beliefs as well.

Why Special Creation Failed - An Introduction to Genetics and the Origin of Species

Special creation, defined as the direct creation of fixed (unchanging) species by God, was the predominant view of the origin of species among scientists during Darwin’s time.  Writes David Reznick in The Origin Then and Now, ‘Today we think of the advocates of special creation as representing non-scientific, religious opponents to evolution.  In Darwin’s day, they were the scientific establishment.  Virtually everyone, ranging from his professors at Cambridge to all those who had the greatest influence on Darwin’s intellectual development, advocated some form of special creation.’

God in the Origin of Species

It is an interesting and much-observed phenomenon that the language of technology can be appropriated for describing the world in new ways.   The best example of this today comes from philosophy of mind and consciousness, where analogies from the computer sciences have helped us envision how the mind operates.  It is interesting to ponder how our concept of mind would have developed without the advent of computer processors.

In the 1600s one of the most remarkable pieces of technology was the clock.  The clock had indeed been around for hundreds of years, but by the late 1500s it had gained an unprecedented level of complexity.  The second Strasbourg clock, for example, which was completed in 1574, contained moving statues and automata, played music, and could track both the time and the movement of celestial bodies.  One of the great ironies of history was that a device whose history began as a simple shadow caused by the movement of the sun, would become one of the most powerful images for the movement of the universe.

Designing Evolution - Christianity's Influence on Darwin

The following is a paper I stumbled on today, that I wrote for my Science and Religion class at Dalhousie on February 13, 2009.  Although it is not nearly as detailed as it deserves, I think its a good introduction to this topic.  Enjoy!  (P.S.  I remember I did well on this paper, but I don't remember how well.  But the clever title was certainly worth an A itself).

A Tale of Four Scholars

In February of 1829 the Earl of Bridgewater died, and left as his legacy 8000 pounds sterling for the express purpose of publishing 1000 copies of a writing ‘On the Power, Wisdom, and Goodness of God, as manifested in the Creation’.  This publication was to be directed by the Royal Society of London, a society which still exists today and is best known for its prestigious scientific journals, Proceedings of the Royal Society and Philosophical Transactions of the Royal Society.  Given today’s inherent assumption that science and religion are in conflict, one would expect the Royal Society to have turned down the Earl of Bridgewater’s final request.  But, shockingly to us, but not to the scientists of the 19^th century, the President of the Royal Society agreed.  Seeking counsel from the Archbishop of Canterbury and the Bishop of London, the President of the Royal Society chose eight of the leading intelligentsia of England and Scotland to publish eight volumes on natural theology.  These eight volumes became the Bridgewater Treatises, and were as follows:

Darwin's Deathbed Confession?

In 1915, an interesting article appeared in the Baptist Boston-based journal Watchman-Examiner.  It was written by one Lady Hope, and read as follows:

‘It was one of those glorious summer afternoons, that we sometimes enjoy in England, when I was asked to go in and sit with the well known professor, Charles Darwin.  He was almost bedridden for some months before he died.  I used to feel when I saw him that his fine presence would make a grand picture for our Royal Academy; but never did I think so more strongly than on this particular occasion.