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COMMON TRANSITION FEATURES. 2. "The division of labour...increased efficiency can result from task specialization. For example, in ribo-organisms, nuclei can acids played two roles, as genetic materials and as enzymes, whereas today most enzymes are proteins." https://lnkd.in/eZ5-m7K View in LinkedIn

EXAMPLES OF #1: "The origin of chromosomes; the origin of eukaryotes with symbiotically derived organelles; the origin of sex; the origin of multicellular organisms...; and the origin of social groups." Loss of independent reproduction. View in LinkedIn

COMMON TRANSITION FEATURES. 1. "Entities that were capable of independent replication before the transition can only replicate as parts of the larger unit after it. For example, free living bacteria evolved into organelles." https://lnkd.in/eZ5-m7K View in LinkedIn

EUTHERIANS. "The first placentals had clearly sacrificed the talocrurals supinatory capability, facilitated by the marsupial meniscus, in favour of re-fashioning the lower extremities of tibia and rubia into a stable mortise for articulation with the re-fashioned talar body." https://lnkd.in/et2pUax View in LinkedIn

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