Vitalism

A few of my thoughts and comments for upcoming lectures related to “life” (thought I’d get in before the assignment is issued).

Vitalism

Definition of “Vitalism” in Henderson’s Dictionary of Biology – “a belief that phenomena exhibited in living organisms are due to a special force distinct from physical or chemical forces”. A “vital force” was seen as necessary in science for life to exist. Some people equated this with the “soul” (and some probably still do).

In the early 1800s chemists could make simple compounds, but artificial synthesis of complex molecules extracted from living matter seemed impossible. A division was made between organic and inorganic compounds, and organic chemistry was based on vitalism. A key blow to vitalism occurred when Hermann Kolbe made ascetic acid (an organic compound) from inorganic substances prepared directly from pure elements. In the following decades vitalism crumbled as more complex organic compounds were synthesised. (reference - “Biology” 8th Ed, by Campbell, Reece and Myers)

Spontaneous Generation

“Spontaneous generation is an obsolete body of thought on the ordinary formation of living organisms without descent from similar organisms. Typically, the idea was that certain forms such as fleas could arise from inanimate matter such as dust, or that maggots could arise from dead flesh. A variant idea was that of equivocal generation, in which species such as tapeworms arose from unrelated living organisms, now understood to be their hosts.” (from Wikipedia)Obviously spontaneous generation is no longer an accepted scientific hypothesis.

Abiogenesis

The precise process for the emergence of life on Earth has not yet been determined. There are several hypotheses and there are many unanswered questions. Abiogenesis is the hypothesis that life emerged over a very long period by gradual increases in complexity in molecular structures. It is clear from research and experiments that abiogenesis is certainly a plausible hypothesis.

What is life?

Viruses are complex macro-molecules that are not considered by most biologists to be alive. Bacteria, on the other hand, are considered to be alive. This claim is based on a definition of life that requires essential functions such as metabolic processes and replication without a host. By this definition, the most basic form of life is a single cell prokaryote, such as bacteria, whereas a virus cannot replicate or metabolise without a host so it is not alive. Life, therefore, depends on what it’s defined to be, and there is no universal agreement in the scientific community on what life is.

Artififcial life

Before 2010, all the steps for creating life have successfully been individually carried out in a laboratory, including self metabolic processes. In 2010, a team at the J. Craig Venter Institute created a synthetic genome that can self-replicate by chemically synthesizing a bacterial genome, then using nuclear transfer techniques to transplant the genome into a bacteria. The bacteria replicated itself, creating a second generation of the synthetic DNA.

http://www.youtube.com/watch?v=QHIocNOHd7A&list=PLDF210C4860053907&index=5

or the ADHD version……..

http://www.youtube.com/watch?v=Lsr-pjGZzLk&list=PLDF210C4860053907&index=8

David Clarke