Happy Birthday Charles Darwin!

Today we celebrate 205 years since the birth of Charles Robert Darwin, the man who provided the world with a rigorous, scientific explanation for the origin and diversity of life that has stood the test of time. His book “On the origin of species by means of natural selection” is rightly celebrated as one of the greatest books ever written.

Darwin 1880

Charles Darwin, 1880.
Image courtesy of Dave Souza

All modern biological thinking owes so much to this man and an understanding of his theory has made it clear that every living thing is inextricably linked. We all share a common ancestor (affectionately named LUCA – Last Universal Common Ancestor) and, through the process of evolution by natural selection as proposed by Darwin, we have diverged over 3.5 billion years into the diversity of life we see around us today.

But what if there had been no Darwin? What if the forces of the universe had been different and this particular baby that was born 205 years ago today in Shrewsbury, England had never entered the world? Would evolution have been explained correctly if Darwin hadn’t been around to do so?

Shaking off creationist thinking

In attempting to answer this question it is important to consider what was known about evolution prior to Darwin and what was it that led Darwin to come up with his theory. We are going back over 200 years and religious thought had a much bigger say in society then than it does today, particularly in western countries.

In fact, the majority of people living in Europe in the 1700s probably wouldn’t have thought that the question “where does life come from?” required much deliberation as they already had an answer – from God.

Not everyone accepted this answer though. The idea of evolution, that living things haven’t come about from one creation event but rather have evolved or changed over time, actually emerged through the work of Darwin’s grandfather Erasmus Darwin (1731-1802). In his work titled Zoonomia, a two-volume medical book, Erasmus penned some initial thoughts on life evolving:

 “Would it be too bold to imagine, that in the great length of time, since the earth began to exist, perhaps millions of ages before the commencement of the history of mankind, …that all warm-blooded animals have arisen from one living filament, which THE GREAT FIRST CAUSE endued with animality, with the power of acquiring new parts, attended with new propensities, directed by irritations, sensations, volitions, and associations; and thus possessing the faculty of continuing to improve by its own inherent activity, and of delivering down those improvements by generation to its posterity, world without end!” (Zoonomia, 1794).

Erasmus Darwin 1792

Erasmus Darwin, Charles’ grandfather, 1792.
Image courtesy of Materialscientist

So, two generations before Charles Darwin, ideas that went against the grain of religious thought and proposed that living things hadn’t been created independently were already being written about. However, what these ideas now needed were some explanation as to how it could actually work within the laws of nature.

Transmutation Theory

The first and most famous pre-Darwin explanation of evolution is the French naturalist Jean-Baptiste Lamarck’s (1744-1829) transmutation theory. Lamarck proposed that organisms initially appeared via spontaneous generation and then, over generations, organisms would become more complex.

He also proposed the idea of an ‘adaptive force’, suggesting beings became adapted to their environments through the more frequent and continuous use of traits leading to those traits being amplified. For example, he would explain a giraffe’s long neck a result of continuous stretching of the neck muscles over many generations.

Conversely, the under-use of a particular trait would lead to that trait being lost, thus explaining blindness in moles. Lamarck stated that these improvements were induced by an organism’s environment and were inherited from one generation to the next.

Lamarck_Giraffes

Lamarck’s theory explained the giraffe’s long neck as the result of stretching over many generations
Image courtesy of Solarist

Close but no cigar. During his time Lamarck’s theory was widely rejected mainly due to a lack of evidence for it. So, even if Darwin hadn’t been around to construct his theory and blow Lamarck’s out of the water, transmutation theory would not have stood the test of time due to the lack of evidence.

As an aside, Lamarckian evolution has recently been brought back into the limelight with the dawn of epigenetics, the theory that the environment can induce changes in the expression of genes of an organism (which, in turn, can affect the phenotype of the organism) during its lifetime and these changes can be heritable, so perhaps Lamarck wasn’t so far off after all.

Enter Charles R. Darwin

So Lamarck’s theory didn’t cut it. A lack of evidence meant that it didn’t stand up as a scientific theory. It became clear that if evolution was going to be explained convincingly then a scientific theory that was testable and backed up by a lot of evidence was going to be required.

Then, in 1809 Charles Robert Darwin entered the world. From a young age Darwin enjoyed collecting things and this happens to be an essential attribute for all good scientists, as all good scientists need to collect lots of evidence.  This compulsive collecting was something that Darwin recognised in himself:

“The passion for collecting, which leads a man to be a systematic naturalist, a virtuoso or a miser, was very strong in me, and clearly innate, as none of my sisters or brother ever had this taste” (from Darwin’s journal)

Thank goodness one of the Darwin clan did have this innate “passion for collecting”! During his voyage on the Beagle he amassed a vast collection of biological specimens and it was whilst considering these collections that the seeds of his theory began to germinate.

An essay by an English cleric and scholar Thomas Malthus also aided Darwin in the development of his theory. From reading “An essay on the principle of population” Darwin came to realise that population growth leads to a struggle for existence and in this struggle those with favourable characteristics would be more likely to survive. This differential survival of individuals as a result of variation between them is the essence of natural selection.

First past the post

There is one integral name that cannot be left out when considering Darwin’s theory and whether or not it would have arisen without him. The British naturalist and explorer Sir Alfred Russell Wallace simultaneously came up with a theory for evolution, which paralleled Darwin’s, whilst carrying out biogeographical research in the Malay Archipelago.

The two men had briefly met once and regularly wrote to each other about their work. In 1858 Darwin received a manuscript from Wallace that outlined his theory. Realising how closely it aligned with his own theory Darwin felt forced to publish what he had been working on for 20 years so not to be beaten to it.

So, perhaps if Darwin hadn’t been born we would instead be talking about Wallace’s theory of evolution and this blog would have been written for the 8th of January in celebration of Wallace’s birthday.

Sir Alfred Russel Wallace 1912

Sir Alfred Russel Wallace, 1912
Image courtesy of Tohma

So, without Darwin we would probably still have a theory of evolution via natural selection. However, it was down to Darwin’s compulsive collecting of specimens as well as his genius to piece all the evidence together that meant that it was him that came up with the theory first. And that is why his name will rightly live long in human history.

 

Happy Birthday Charles Darwin.

About Matt_Christmas

My interest in and enthusiasm for science led me to become a high school science teacher in the UK. After having moved to Australia in 2011, I now find myself on the long winding road towards a doctorate in the field of ecological genomics at the University of Adelaide. My research involves looking into plant adaptation in the face of a changing climate, which I hope will have practical applications to help protect the threatened natural environment around us. Science communication is a passion of mine and I believe getting our work into the public arena is a responsibility of all scientists.

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