Notas

The chimpanzee and the human share about 99.5% of their evolutionary history

Theory and quantitative data from the social insects demonstrate that there is no inherent tendency for parents to dominate their offspring (or vice versa)

Erroneous assumption: the important thing in evolution is the good of the species (or the group) rather than the good of the individual (or the gene)

Behavioral definitions: An entity is said to be altruistic if it behaves in such a way as to increase another such entity’s welfare at the expense of its own. Selfish behavior has exactly the opposite effect

Chosen examples are never serious evidence for any worthwile generalization

A human fetus, with no more human feeling than an amoeba, enjoys a reverence and legal protection far in excess of those granted to an adult chimpanzee

The ethics of speciesism have no proper basis in evolutionary biology

The fundamental unit of selection, and therefore of self-interest, is not the species, nor the group, nor even the individual. It is the gene, the unit of heredity

Darwin’s “survival of the fittest” is really a more general law of “survival of the stable”

A stable thing is a collection of atoms that is permanent enough or common enough to deserve a name

Sometimes when atoms meet they link up together in chemical reaction to form molecules, which may be more or less stable. A crystal such as a diamond can be regarded as a single molecule, its internal structure is endlessly repeated

No design, no purpose, no directedness. If a group of atoms in the presence of energy falls into a stable pattern, it will tend to stay that way

The earliest form of natural selection was simply a selection of stable forms and a rejection of unstable ones

Chemists have put water, carbon dioxide, methane and ammonia in a flask and supplied a source of energy such as ultraviolet light or electric sparks (artificial simulation of primordial lightning). After weeks of this, a weak brown soup containing a large number of molecules more complex than the original ones are found inside: amino acids

Amino acids are the building blocks of proteins

Proteins are one of the two great classes of biological molecules

Laboratory simulations of the chemical conditions of earth before the coming of life have yielded organic substances called purines and pyrimidines

Purines and pyrimides are the building blocks of the genetic molecule, DNA itself

The “primeval soup” must have been caused by processes like the experiments involving basic molecules

DNA molecules are astonishingly faithful when replicating, but they occasionally make mistakes, and it is ultimately these mistakes that make evolution possible. Some varieties are inherently more stable than others

If replicator molecules of type A make copies of themselves on average once a week, while those of type B make copies of themselves once an hour, A will be far outnumbered even if they live much longer than B

Accuracy of replication allows for greater survival of a defined category of molecule

Nothing actually “wants” to evolve, structure just happens

A long process of genetic replicating errors which allowed to break up molecules of rival varieties chemically and use the released building blocks for making their own copies eventually emerged

Another long process of genetic replicating errors eventually stumbled upon “survival machines” for themselves to live in

In their fundamental chemistry, an octopus, a mouse, an elephant and an oak tree’s replicator molecule, their gene molecules, are basically the same. A monkey is a machine that preserves genes up trees, a fish is a machine that preserves genes in the water, one type of worm even preserves genes in German beer mats.

A DNA molecule is a long chain of small molecules called nucleotides. Its exact shape, worked out by indirect means, consists of a pair of nucleotide chains twisted together in an elegant spiral; the ‘double helix’; the ‘inmortal coil’

The nucleotides come in only four different kinds: Adenine, Thymine, Cytosine and Guanine

There are about a thousand million million cells making up an average human body

Every cell contains a complete body of that body’s DNA, written in the A, T, C, G alphabet. Held by the bucleus, with 46 chromosomes in humans that consist of 23 pairs of chromosomes: one copy of the same feature from each of the parents (for example, the same section of each chromosome in a pair might be both ‘about’ eye colour, perhaps one ‘says’ blue while the other says brown)

The DNA indirectly supervises the manufacture of a different kind of molecule: the protein

Proteins not only constitute much of the physical fabric of the body, they also exert sensitive control over all the chemical processes inside the cell, selectively turning them on and off at precise times and in precise places

No matter how much knowledge or wisdom you acquire during your life, not one jot will be passed on to your children by genetic means. Each new generation starts from scratch. A body is the genes’ way of preserving the genes unaltered

If each version of the same section of the chromosome make contradictory ‘recommendations’, what the body does varies. Sometimes, one reading prevails the other and the other is ignored. An ignored gene is called ‘recessive’, the opposite of that is the ‘dominant’ gene. When two genes are rivals for the same slot on a chromosome, they are called ‘alleles’ of each other. (As an example, the gene for brown eyes is usually dominant to the gene for blue eyes)

The genes of a given population can be regarded as a ‘gene pool’

The normal division of a cell into two cells, where each one recieves a complete copy of all 46 chromosomes, is called ‘mitosis’. ‘Meiosis’ occurs only in the production of the sex cells: sperms or eggs

Sperms and eggs assemble in 23 chromosomes from different bits of the original body’s chromosome pairs. It may grab one proportion of chromosome A of the body’s sperm parent, and the remaining proportion of chromosome B of the body’s egg parent. This makes it so that basically all sperms are unique and all eggs are unique. The process of swapping bits of chromosome is called ‘crossing over’

It would be a waste of time trying to identify chromosome bits that originally came from your father and bits that originally came from your mother

Chromosomes have something akin to punctuation marks, they are special symbols for END OF PROTEIN CHAIN MESSAGE and START OF PROTEIN CHAIN MESSAGE written in the A, T, C, G alphabet. In between these two marks are the coded instructions for making one protein. The word ‘cistron’ has been used for a unit defined in this way. Crossing-over does not respect boundaries between cistrons

The shorter a genetic unit is, the longer it is like to live (in generations). The life-span of a chromosome is one generation; 1/100 of the length of a chromosome has a 99% chance of being from a parent of the parent

‘Point mutation’ is an error corresponding to a single misprinted letter in the A, T, C, G code. The longer a genetic unit is, the more likely it is to be altered by a point mutations. One rare kind of mistake or mutation is called ‘inversion’, where a piece of chromosome detaches itself at both ends, turns head over heels, and reattaches itself in the inverted position

‘Mimicry’: when a fenotype is very similar to another species which, in turns, makes the mimic species survive more. (Like butterflies that taste nasty and have some color pattern, so delicious butterflies “mimic” the color so they are not eaten)

It was the great achievement of Gregor Mendel to show that hereditary units can be treated in practice as indivisible and independent particles

Sexual reproduction is not replication. Individuals aren’t stable things, chromosomes are unstable as well. The genes are the practically intact survivor