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Why are There so Many Species of Beetles and So few Crocodiles?

By Guest PostAugust 29, 2012Nature, Scienceadaptive zone, alligators, beetles, biodiversity, bird, cichlid fish, crocodile, daniel rabosky, diversity tree, ecological limits, eukaryote, evolutionary biology, evolutionary detectives, factor, fish, fungi, graham slater, life, lizard, mammal, michael alfaro, multi cellular, new zealand, planet, puzzle, reptile, snake, species, species diversity, species richness, theoretical model, tree of life, tuatara

Answer may be ‘adaptive zones’ that limit species number, life scientists report

There are more than 400,000 species of beetles and only two species of the tuatara, a reptile cousin of snakes and lizards that lives in New Zealand. Crocodiles and alligators, while nearly 250 million years old, have diversified into only 23 species. Why evolution has produced “winners” — including mammals and many species of birds and fish — and “losers” is a major question in evolutionary biology.

Scientists have often posited that because some animal and plant lineages are much older than others, they have had more time to produce new species (the dearth of crocodiles notwithstanding). This idea — that time is an important predictor of species number — underlies many theoretical models used by biologists. However, it fails to explain species numbers across all multi-cellular life on the planet, a team of life scientists reports Aug. 28 in the online journal PLoS Biology, a publication of the Public Library of Science. (more…)

Iconic New Zealand Reptile Shows Chewing is Not Just for Mammals

The tuatara, an iconic New Zealand reptile, chews its food in a way unlike any other animal on the planet –challenging the widespread perception that complex chewing ability is closely linked to high metabolism.

Using a sophisticated computer model, scientists from UCL and the University of Hull demonstrate how the tuatara is able to slice its food like a “steak knife”. The tuatara’s complex chewing technique raises doubts about the supposed link between chewing and high metabolism in mammals.

The New Zealand tuatara (Sphenodon) is a lizard-like reptile that is the only survivor of a group that was globally widespread at the time of the dinosaurs. It lives on 35 islands scattered around the coast of New Zealand and was recently reintroduced to the mainland. Its diet consists of beetles, spiders, crickets, small lizards and, occasionally, sea birds. (more…)

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Why are There so Many Species of Beetles and So few Crocodiles?

Iconic New Zealand Reptile Shows Chewing is Not Just for Mammals