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MAJOR EVOLUTIONARY TRANSITIONS: 1. Replicating molecules to populations of molecules in compartments; 2. Unlinked replicators to chromosomes; 3. RNA as GENE and enzyme to DNA and protein (genetic code); 4. Prokaryotes to eukaryotes; 5. Asexual clones to sexual populations; 6. Protists to animals, plants and fungi (cell differentiation); 6. Solitary individuals to colonies (non-reproductive castes); 7. Primate societies to human societies (language). https://lnkd.in/eZ5-m7K View in LinkedIn

DERIVATION. "The human ankle bears the clear imprint of derivation from arboreal primates which in turn were doubtless derived from very early unspecialized eutherians." https://lnkd.in/et2pUax View in LinkedIn

SZATHMÁRY & MAYNARD SMITH. "There is no theoretical reason to expect evolutionary lineages to increase in complexity with time, and no empirical evidence that they do so. Nevertheless, eukaryotic cells are more complex than prokaryotic ones, animals and plants are more complex than protests, and so on. This increase in complexity may have been achieved as a result of a series of major evolutionary transitions. These involved changes in the way information is stored and transmitted." A classic paper. https://lnkd.in/eZ5-m7K View in LinkedIn

TALUS & CALCANEUS. "A key event in transforming the therapsid foot into a mammalian one was the superimposition of the talus upon the calcaneus. This introduced a new flexibility into the foot by providing for inversion and eversion at the subtalar joint complex." https://lnkd.in/et2pUax View in LinkedIn

THE NEXT SECTION deals with major evolutionary transitions. These events have shaped life on earth, but our understanding of them is, as usual, rather scant. However, this is a very interesting topic, and some great thinkers have applied themselves to the topic. View in LinkedIn

PASSING THROUGH. "It seems quite clear that the anatomy of living marsupials (metatherians) gives a good indication of the structure of those advanced early Cretaceous therians from which the first placentals (eutherians) evolved. One might say, as has Lillegraven (1974) that the eutherians passed through a metatherian grade." https://lnkd.in/et2pUax View in LinkedIn

IN TRANSITION. "However, evidence casting doubt that most of the human genome possesses a functional role has existed for some time. This is not to say that none of the nonprotein-coding majority of the genome is functional—examples of functional noncoding sequences have been known for more than half a century, and even the earliest proponents of “junk DNA” and “selfish DNA” predicted that further examples would be found." http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1004351 View in LinkedIn

TARSAL RANKING. "Recent studies, and the present paper indicate that evolving foot form is replete with apomorphic characters, and moreover, that these can be keyed to reasonable functional and adaptive roles. Gregory (1910) perceptively recognized the potential importance of characters of the feet, particularly tarsals, even ranking them above teeth!" (Apomorphic = unique species trait). https://lnkd.in/er98r8i View in LinkedIn

TALUS UPON THE CALCANEUS. "Schaeffer (1941) rightly stressed that the therapsid foot was converted into a mammalian one by superposition of the talus upon the calcaneus, correlated with a loss of weight-bearing contact between fibula and calcaneus; but little is known about how the complex articular surfaces and ligamentous apparatus of the mammalian foot came into being." https://lnkd.in/er98r8i View in LinkedIn

COMPETITIVE ADVANTAGE. "There is little doubt that one of the major evolutionary assets of therian mammals was a complex foot architecture with subtly integrated articular complexes at the ankle, subtalar and traverse tarsal joints." A brilliant three part anatomical analysis of the foot across species (OJ Lewis, St Bartholemew's Hospital, London). (Therian = marsupials and placentals). https://lnkd.in/er98r8i View in LinkedIn