Macroevolution
[4][10][11] Macroevolution addresses the evolution of species and higher taxonomic groups (genera, families, orders, etc) and uses evidence from phylogenetics,[5] the fossil record,[9] and molecular biology to answer how different taxonomic groups exhibit different species diversity and/or morphological disparity.
[12] After Charles Darwin published his book On the Origin of Species[13] in 1859, evolution was widely accepted to be real phenomenon.
Prior to the modern synthesis, during the period between the 1880s to the 1930s (dubbed the ‘Eclipse of Darwinism’) many scientists argued in favor of alternative explanations.
[11] While introducing the concept, he claimed that the field of genetics is insufficient to explain “the origin of higher systematic units” above the species level.
So vorteilhaft es für uns auch wäre, uns auch in dieser Frage auf die exakten Resultate der Genetik zu stützen, so sind sie doch, unserer Meinung nach, zu diesem Zweck ganz unbrauchbar, da die Frage über die Entstehung der höheren systematischen Einheiten ganz außerhalb des Forschungsgebietes der Genetik liegt.
In such a state of affairs, it must be admitted that the decision of the question depends on the factors of the larger features of evolution, of what we call macroevolution, must occur independently of the results of current genetics.
Furthermore, the Linnaean ranks of ‘genus’ (and higher) are not real entities but artificial concepts which break down when they are combined with the process of evolution.
The term was adopted by Filipchenko's protégé Theodosius Dobzhansky in his book ‘Genetics und the Origin of Species’ (1937), a seminal piece that contributed to the development of the Modern Synthesis.
A notable example of this was the book The Material Basis of Evolution (1940) by the geneticist Richard Goldschmidt, a close friend of Filipchenko.
[18] Particularly the latter idea was widely rejected by the modern synthesis, but the hopeful monster concept based on Evolutionary developmental biology (or evo-devo) explanations found a moderate revival in recent times.
This view became broadly accepted, and accordingly, the term macroevolution has been used widely as a neutral label for the study of evolutionary changes that take place over a very large time-scale.
[4] The fact that both micro- and macroevolution (including common descent) are supported by overwhelming evidence remains uncontroversial within the scientific community.
Hence, the patterns observed at the macroevolutionary scale can be explained by microevolutionary processes over long periods of time.
Thus, macroevolution is concerned with the history of life and macroevolutionary explanations encompasses ecology, paleontology, mass extinctions, plate tectonics, and unique events such as the Cambrian explosion.
[1] More questions can be asked regarding the evolution of species and higher taxonomic groups (genera, families, orders, etc), and how these have evolved across geography and vast spans of geological time.
For example: According to the modern definition, the evolutionary transition from the ancestral to the daughter species is microevolutionary, because it results from selection (or, more generally, sorting) among varying organisms.
[2] Speciation is the process in which populations within one species change to an extent at which they become reproductively isolated, that is, they cannot interbreed anymore.
[32] The advent of genome sequencing enabled the discovery of gradual genetic changes both during speciation but also across higher taxa.
For instance, the evolution of mammal diversity in the past 100 million years has not required any major innovation.
Even fundamental tissues such as bone can evolve from combining existing proteins (collagen) with calcium phosphate (specifically, hydroxy-apatite).
His iconic diagram of the numbers of marine families from the Cambrian to the Recent illustrates the successive expansion and dwindling of three "evolutionary faunas" that were characterized by differences in origination rates and carrying capacities.
Long-term ecological changes and major geological events are postulated to have played crucial roles in shaping these evolutionary faunas.
[4] Stanley's rule, which applies to almost all taxa and geologic ages, is therefore an indication for a dominant role of biotic interactions in macroevolution.
Another species of bacteria, Jeongeupia sacculi, form well-ordered sheets of cells, which ultimately develop into a bulbous structure.
In several clades of lizards, egg-laying (oviparous) species have evolved into live-bearing ones, apparently with very little genetic change.
For instance, a European common lizard, Zootoca vivipara, is viviparous throughout most of its range, but oviparous in the extreme southwest portion.
Similar cases are known from South American lizards of the genus Liolaemus which have egg-laying species at lower altitudes, but closely related viviparous species at higher altitudes, suggesting that the switch from oviparous to viviparous reproduction does not require many genetic changes.
For instance, the African striped mouse (Rhabdomys pumilio), transitioned from the ancestrally nocturnal behavior of its close relatives to a diurnal one.
Genome sequencing and transcriptomics revealed that this transition was achieved by modifying genes in the rod phototransduction pathway, among others.
