Natural selection/Mayr: is no random process! (Although coincidence happens in evolution).
Selection/Mayr: is today completely accepted. Two steps: variation and actual selection.
1. Variation: In each generation, recombination, gene flow, random factors and mutations generate a great genetic diversity. The genetic material is "hard" and not "soft", as Darwin assumed.
Sexual Reproduction: the parental chromosomes are broken and reassembled. Thus uniqueness of the offspring by recombination. Composition of the genes according to no law!
2.Selection: differences in the survival and reproduction of newly formed individuals. Even in species producing millions of offspring in each generation, on average, only two of them are needed to maintain population balance.
Coincidence/Mayr: dominates the variation.
Necessity/Mayr: dominates the selection.
Selection: there is no "selective force"!
Selection: Bates' discovery of mimicry (1862) in edible and poisonous butterflies: first proof of natural selection.
Benefits/Biology: what is the benefit of the emergence of a characteristic for survival: adaptionist program.
Characteristics/Survival: favourable characteristics: Tolerance against adverse climate, better utilisation of food, resistance to pathogens, escape capability. (through sexual reproduction). Selection by females (peacock tail) may be more important than the ability of males to defeat rivals.
Brother and sister rivalry and parental care: affect reproductive success rather than survival. This selection is apparently more important than the concept of sexual selection suggests.
Extinction: 99.9% of all evolutionary lines that once existed on Earth are extinct.
Selection: Darwin: "Natural selection is on an hourly basis all over the world to detect the slightest changes".
Selection/MayrVsDarwin: the genetic variation needed to perfect a characteristic may not occur at all!
For example, the inner/outer skeleton: vertebrates up to the dinosaur, outer skeleton: the giant crab has remained the largest creature. The difference is determined by the different paths taken by the ancestors, not by the presence of characteristics!
Selection/Mayr: further restriction: interaction in development. The parts of the organism are not independent of each other. No one reacts to the selection without interacting with the other characteristics.
Geoffroys, 1818: "Law of Balance": Organisms are compromises between competing demands.
Selection/Mayr: 3rd Restriction: Ability to non-genetic modification: the more plastic the phenotype (due to flexibility in development) is, the less the force of selection pressure. Plants (and especially microorganisms) have a much greater ability to phenotypic modification (more diverse reaction standard) than animals.
Ability for non-genetic adaptation is exclusively genetically controlled!
Coincidence: works at every level.
New: whole populations or even species could be the target of the selection.
Soft/hard group selection.
Soft group selection: Success through the average selection value of the individuals. This means that each individual selection is also a soft group selection.
Hard group selection: the group as a whole has certain adaptive group characteristics that are not simply the sum of the contributions, the advantage of the group is greater than that of the sum of the individual members. Division of labor, cooperation (guardian, search for food). Here the term "group selection" is justified.
Origin of the species: this controversy completely changed the status of so-called species selection: the emergence of a new species seems to contribute very often to the extinction of another species. "Species Exchange," takes place according to strict Darwinian principles.
Definition r selection: strongly fluctuating, often catastrophically exposed population size, weak intraspecific competition, very fertile.
K Selection: constant population size, strong competition, stable life expectancy.
As population density increases, so too does the influence of adverse factors: competition, food shortages, lack of escape routes, predators, > growth slows down.
Could the human being become a superhuman? The odds are not so good here! Not enough selection pressure. Group selection was particularly a thing of the past.
Selection/Human: Today, however, in mass society there is no sign of selection for superior genotypes that would allow the human being to rise above its present abilities.
Many authors even claim that the human gene pool is decaying.
Francis Galton (Darwin's cousin) was the first to suggest that one could and should improve humanity with appropriate selection. He coined the term "eugenics"._____________Explanation of symbols: Roman numerals indicate the source, arabic numerals indicate the page number. The corresponding books are indicated on the right hand side. ((s)…): Comment by the sender of the contribution.
Das ist Biologie Heidelberg 1998