Posts Tagged ‘Lamarck’

Scientists Mutate Flatworms without Altering Genes

November 28, 2015

This is another very interesting piece I found on Tumblr. Biologists at Tufts University have managed to make one species of flatworm grow the brains and heads of other species without altering its genetic makeup. This suggests that the body plan of living creatures may be partly determined by the bioelectric fields and synapses, and develop according to epigenetic processes. These are the biological processes that affect the shape of living being which aren’t caused by that creature’s genes.

Flatworm EvolutionPic

It’s a fascinating addition to modern evolutionary theory, which takes it beyond the simple Neo-Darwinian synthesis formulated at the beginning of the 20th century by Theodososius Dobzhansky and Fisher, amongst others. This stated that evolution worked through the appearance of mutations in living creatures’ genetic codes, which provided the raw material for the operation of Darwin’s natural selection. If the mutations proved beneficial, then the creature thrived and had more offspring, and the genes spread through the rest of that creature’s population. If the mutations were harmful, then the creature died, taking with it the faulty genes. Gradually these mutations, selected by the environment, mounted up until a new species emerged, descended from its predecessor.

This complicates the situation. There’s a theory that Lamarck based his theory that evolution was driven through inherited characteristics partly on misunderstood observations of epigenetic alterations in the animals he studied. Some of the changes can be quite dramatic. For example, some species of animal have been known to develop additions to the digestive system according to changes in diet. John Maynard Smith, one of the leaders and founders of modern Neo-Darwinian biology, also speculated in a small book published on evolution in the 1990s that the forms of living creatures may also be partly determined by the changes in the developing embryo in the very first stages of life. I’ve been told that there’s a heretical view of the development of living organisms held by a few university biologists, which states that these changes are largely responsible for the shape of the organism, with the creature’s genes determining only minor differences.

This experiment adds more information to the debate, and seems to support the indications that epigenetics – non-genetic processes – could play a stronger role in shaping living things than previously considered.

Lamarck: The Faith of An Evolutionist

April 27, 2013

In the last post, I criticised the otherwise excellent BBC series with Bill Bailey on Wallace for presenting evolutionary as leading to atheism. During the late eighteenth and early nineteenth century, some of the founders of evolutionary theory were convinced it led in the other direction: to God. Darwin’s grandfather, Erasmus Darwin, also formed a theory of evolution in his Zoonomia. This was a best-seller, though its popularity was cut short when the French Revolutionary Wars broke out. Scientific attempts to investigate the origin of species, in Charles Darwin’s later phrase, became associated with atheism, revolution and carnage. Erasmus Darwin, however, beleived his theory made the existence of the Lord ‘mathematically certain’.

The other, major figure of evolutionary theory before Charles Darwin was Jean-Baptiste Lamarck. Lamarck was the professor of Insects, Worms and Microscopic Animals at the Jardin des Plantes. He articulated his theory of evolution in a seris of books, the Systeme des Animaux sans Vertbres of 1801, the Philosophie Zoologique, of 1809 and the Histoire Naturelle des Aminaux sans Vertebres of 1815. In his view, which became known as Lamarckianism after him, evolution progressed as animals acquired new characteristics, which were then passed down to their offspring. As a theory of evolution its has long been discarded, though the recent studies of epigenetics does show how the environment can affect the physiology and structure of living creatures as well as their genetic inheritance. Unlike some of his contemporaries, Lamarck was a Deist rather than an atheist. He appears to have followed the 18th century German philosopher Leibnitz in believing that God created all possible things. He also had a teleological view of evolution, in which evolution led to higher forms of life. He also followed the ancient philosophers in believing that ‘Nature made no jumps’ – in other words, that organisms ultimately shaded into each other. Like later theistic evolutionists, he believed that evolution was only an instrument through which God produced new forms of life. In the first volume of his Animaux sans Vertebres he wrote:

‘The general power which holds in its domain all the things we can perceive .. is truly a limited power, and in a manner blind; a power which has neither intention, nor end in view, nor choice; a power which, great as it may be, can do nothing but what in fact it does; in a word, a power which only exists by the will of a higher and limitless power, which, having founded it, is in turth the author of all that it produces, that is, of all that exists …

‘And nature … is only an instrument, only the particular means which it has pleased the supreme power to employ in the production of various bodies, in their diversification; to give them properties, or even abilities… She is, in a way,, only an intermediary between GOD and the parts of the physical universe, for the execution of the divine will.’

Like Richard Dawkins, Lamarck believed that there was a blind watchmaker. This watchmaker, however, was wielded by one who was All-Seeing, and whose powers stretched beyond the tool He used for crafting His Creatures.

Rebecca Stott, Darwin’s Ghosts: In Search of the First Evolutionists (London: Bloomsbury 2012)

J.S. Wilkie, ‘Buffon, Lamarck and Darwin: The Originality of Darwin’s Theory of Evolution’ in C.A. Russell, (ed.) Science and Religious Belief: A Selection of Recent Historical Studies (London: University of London Press 1973)238-281.