Excerpt: ‘One possible explanation of how this diversity evolved is the “niche filling” model of adaptive radiation—under which evolutionary rates are highest early in the evolution of a group, as lineages diversify to fill disparate ecological niches.”
Excerpt: “The evolutionary line leading to birds kept experimenting with different, often radically smaller, body sizes — enabling new body ‘designs’ and adaptations to arise more rapidly than among larger dinosaurs. Other dinosaur groups failed to do this, got locked in to narrow ecological niches, and ultimately went extinct.”
My comment: In the context of ecological variation and adaptations, the authors accurately claim that: “Much of extant biodiversity may have arisen from a small number of adaptive radiations…” Compare that statement to this misrepresentation: “…genomic conservation and constraint-breaking mutation is the ultimate source of all biological innovations and the enormous amount of biodiversity in this world.” — Masatoshi Nei (2013).
To confirm the accuracy of the claim for adaptive radiations and extant biodiversity one need only look at the ecological adaptations associated with frugivory in mammals (e.g., in bats and in humans). Compare the ecological adaptations manifested in morphology and behavior, which are associated with the epigenetic effects of vitamin C on genome and phenome stability, to their basis in the ecological variation that led to ecological adaptations in birds.
The dinosaur-to-bird comparison introduces a component of missing heritability into what is currently known about biophysically constrained ecological adaptations. Simply put, the metabolism of food to species-specific pheromones controls the physiology of reproduction in all species and nutrient-dependent pheromone-controlled reproduction leads to species diversity. Therefore, to determine what happened to the dinosaurs, one need only look at nutrient-dependent variations in the morphological and behavioral phenotypes of white-throated sparrows, which are primarily associated with a difference in parental feeding behaviors. Bi-parental feeding is associated with morphological and behavioral phenotypes.
Clearly it is ecological, social, neurogenic, and socio-cognitive niche construction that underlies the ability to adapt to ecological variation in vertebrates like these sparrows, and in every species of invertebrate that ever existed. Those that did not ecologically adapt became extinct.
From experimental evidence in the white-throated sparrow morphs, we know that dinosaurs did not mutate into different species of birds. From experimental evidence in other species, we know that they did not mutate into existence. Thus, pseudoscientific claims that “constraint-breaking mutation” is responsible for biodiversity, may be supported by methods used in population genetics, but those claims are not supported with experimental evidence of biological facts in species from dinosaurs to birds, or in any extinct or ecologically adapted extant species. Ecological variation leads to nutrient-dependent pheromone-controlled ecological adaptations, not to mutation-initiated natural selection and evolution.