Is man just an animal?

Theodosius Dobzhansky

Modern biologists frequently say that man is not special, that we are just a species among many. Thus, for instance, Colin Tudge writes this:

Phylogenetically we are an outpost, a tiny figment of life, just as Earth is a cosmological nonentity that no other intelligent life-form in the Universe would bother to put in their celestial maps.

(The variety of life, Oxford University Press, 2000).

This is just the indiscriminate application of a pseudo-scientific dogma that few biologists would dare contradict, which can be expressed in one of the following equivalent ways:

• All species of living beings are equivalent; no one is superior to the others.
• There are no criteria that make it possible to compare the importance of different species.
• Man is not superior to chimps, ants, bacteria...
• Evolution has no direction.

Evolution and progress

Friedrich Nietzsche

In the late nineteenth century, many biologists and thinkers, atheists or agnostics, relied on Darwin's theories to build philosophical schools that combined the newly discovered evolution with the eighteenth-century idea of ​​progress, to assert that the history of life and man shows clear traces of indefinite progress, and to predict that such progress will continue indefinitely into the future.

Among the biologists who ascribed to these theories the best known are T.H. Huxley and Ernest Haeckel. The philosophers were many, each one giving rise to a school of his own, often incompatible with those of others: Karl Marx (Marxism), Herbert Spencer (social Darwinism), Auguste Comte (positivism) and Friedrich Nietzsche (nihilism) were the more influential. In their forecasts for the future of evolution, the last-mentioned was the most exalted and predicted that man would soon be succeeded and supplanted by a superior species, the superman.

Scientific fraud, a danger for science

Piltdown man

Fraudulent activity is not exclusive of politicians and the world of finances, though perhaps it is more widespread in those fields. It also affects scientists, who, like every human being, are prone to temptation and sometimes (surprisingly rarely) fall into it. The reasons are the usual: ambition, fame and the unbearable pressure to publish results.

The first thing we must do is find out what is fraud and what it is not. According to the criteria used in the United States, there are just two essentially fraudulent scientific activities: plagiarism and the invention or falsification of experimental results. The following activities are questionable, but not fraud: mistaking speculation with fact; incorrect use of statistical procedures; seeking approval after the fact for ethically controversial experiments. Finally, the following activities must not be considered fraudulent or questionable: judgment errors, differences of opinion in the interpretation of data, or involuntary errors in their analysis.

The invention of the genetic code

As is well known, the genetic code is the representation of the amino acid sequence of proteins by means of DNA strands. Now, the proteins of living beings are made of 20 different amino acids. However, there are only four different nucleotides in DNA. How can just four bases represent 20 amino acids?

With codons made of two nucleotides just 16 amino acids could be represented. As they are 20, two nucleotides are not enough: three must be used. Indeed, that is what life has done: each amino acid is represented by codons made of three nucleotides. The problem is, three nucleotides could represent 64 different amino acids, rather than 20 (21, considering that there codons mark the end of the string). What is the solution? Obviously, some amino acids must be represented by several codons (this is what is called degeneracy of the genetic code).

The four DNA nucleotides are made of a skeleton of sugar and phosphoric acid, combined with a nucleobase. In DNA there are four different bases:

• Two purines (P): adenine (A) and guanine (G).
• Two pyrimidines (Q): cytosine (C) y thymine (T).

The final anthropic principle and the antiChrist

Pierre Teilhard de Chardin

In their popular science book, The Anthropic Cosmological Principle, published in 1986, cosmologists John Barrow and Frank Tipler define three different anthropic principles:

1.      The weak anthropic principle or WAP (this was offered by Brandon Carter in 1973): the simple verification that the fact that we are here imposes certain restrictions on the universe, such as having lasted long enough for intelligent life to appear.

2.      The strong anthropic principle or SAP: the claim that making possible the emergence of intelligent life was a necessary requirement for the universe.

3.      The final anthropic principle or FAP: The claim that, once intelligent life has appeared in the universe, it cannot disappear.

Are we alone in the galaxy?

Enrico Fermi

In their famous book of hard scientific popularization, The Anthropic Cosmological Principle, published in 1986, the cosmologists John Barrow and Frank Tipler offer a proof that we are alone in the galaxy by means of a variant of the Fermi paradox (if there are any extraterrestrial intelligences in the Galaxy, why aren’t they here?) which can be summarized as follows:

1.      In 100 years we will have succeeded in creating life in the laboratory. Not just life, we will also be able to build a complete human being from its chemical components and information about the human genome, which can be stored in a digital memory.

2.      In 100 years we will have managed to build artificial intelligences as intelligent as human beings, able to replace us in any place and circumstance.

3.      Our current space technology allows us to reach a speed of 0.0003 c (where c is the speed of light). At that speed, a spaceship would take about 50,000 years to reach the nearest stars.

How eukaryotic cells arose

Examples of eukaryotes

The discovery that there are two main types of living cells (prokaryotes and eukaryotes) gave rise to a revolution in the way of classifying living things. Although (as usual) biologists do not agree on a single classification, the following one seems very reasonable:

1.      Empire prokaryote (bacteria). DNA free in the protoplasm.

a.       Kingdom eubacteria (true bacteria). They use acyl ester lipids.

b.      Kingdom archaea. They use isoprenoidal-ether lipids. They include sulphobacteria, methanobacteria and halobacteria.

2.      Empire eukaryote (cells with nuclei). DNA inside the nucleus. They have a cytoskeleton.

c.       Kingdom archaezoa (primitive eukaryotes). They have no organelles.

d.      Kingdom protozoa (advanced unicellular eukaryotes) with symbiotic organelles.

e.       Kingdom Fungi.

f.       Kingdom metaphyta (plants).

g.      Kingdom of metazoa (animals).