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Mystery pavement: great trouble and relative expense to put this ribbed slab of marly limestone at the doorstep. To take the mud off the wheels of carts? Not known, by me at least. View in LinkedIn

SO ENDS this second weekend looking at the transition of the whale family of vertebrates back to the sea. This complicated evolution, once from the sea to the land, and then back again is an example of adaptive plasticity. The phenotype is moldable clay, that can endure seemingly unlimited changes during evolution, turning limbs into wings in some insects, and wrenching the faces of flatfish from vertical orientation. But the whales are a wonderful example of wholesale remodeling of not just anatomical phenotype, but physiology and metabolism by the direction of genes. View in LinkedIn

MOLECULAR UNDERPINNINGS. "Cetacea (whales, dolphins, and porpoises) is a model group for investigating the molecular signature of macroevolutionary transitions. Recent research has begun to reveal the molecular underpinnings of the remarkable anatomical and behavioral transformation in this clade. This shift from terrestrial to aquatic environments is arguably the best-understood major morphological transition in vertebrate evolution." https://lnkd.in/d8XpCvA View in LinkedIn

OTHER ADAPTATIONS. "Some cetaceans show extreme longevity, as well as resistance to cancer, wound healing and insulin resistance. Other major adaptations pertain to feeding ecology; indeed, modern cetaceans diverged approximately 34 Ma into the toothed whales (suborder Odontoceti), which evolved echolocation to hunt using ultrasonic pulses and possess a highly specialized inner ear, and the baleen whales (suborder Mysticeti), which lost their teeth and instead evolved a novel keratinous material for filtering smaller prey." http://rsos.royalsocietypublishing.org/content/2/9/150156 View in LinkedIn

EXTREME SPECIALIZATION. "Cetaceans are arguably the most specialized of all mammals, having evolved from a terrestrial ancestor to occupy an obligate aquatic niche. Modern cetaceans show numerous phenotypic adaptations for life in the water; aside from the radical reorganization of their forelimbs into fins and loss of hindlimbs, they are able to dive and tolerate low oxygen, and possess modified circulatory and respiratory systems, large brains, hairlessness and transformations in sensory perception." https://lnkd.in/d6aiUba View in LinkedIn

ENORMOUS SUCCESS. "The cetaceans, including whales, dolphins and purpoises, are thought to be among the most successful animals to have ever transitioned from land back to the sea, beginning about 50–55 Ma. Over eons, along with losing limbs and hair, growing tails, and gaining blubber, the remarkable evolutionary changes also included a dramatic dietary change, from herbivorous to carnivorous." https://lnkd.in/dHjVr6G View in LinkedIn

SKELETAL CHANGES. "Cetaceans have highly transformed pelvic and hindlimb bones as a secondary adaptation to an aquatic lifestyle. Paleontological records of these bones are very scarce, which hampers interpretations of their homology and evolution." https://lnkd.in/dn9zKpQ View in LinkedIn

FERMENTATIVE METABOLISMS. "Baleen whales, which prey on animals (fish and crustaceans), harbor unique gut microbiomes with surprising parallels in functional capacity and higher level taxonomy to those of terrestrial herbivores. These similarities likely reflect a shared role for fermentative metabolisms despite a shift in primary carbon sources from plant-derived to animal-derived polysaccharides, such ras chitin." https://lnkd.in/dDPhaBp View in LinkedIn

APPLES AND ORANGES. "By definition, learning is a process for acquiring memories by which adaptive changes in an organism’s behaviour arise as a result of experience. Recognizing and quantifying such behavioral changes has proven to be no easy task in human and animal subjects, let alone in plants whose ability to behave is still an underappreciated phenomenon." https://lnkd.in/dH68RKn View in LinkedIn