Skeletons: The Frame of Life pdf

Jan Zalasiewicz, professore di paleobiologia all'Università di Leicester, approfondisce l'Antropocene. Jan Zalasiewicz è Professore di Paleobiologia all'Università di Leicester, Regno Unito. All'inizio della sua carriera è stato geologo sul campo e paleontologo presso il British Geological Survey, lavorando per decifrare gli strati dell'Inghilterra orientale e poi le montagne del Galles centrale. Ora insegna geologia e storia della Terra a studenti universitari e post-laurea e studia ecosistemi e ambienti fossili in oltre mezzo miliardo di anni di tempo geologico. Negli ultimi anni è stato coinvolto nello sviluppo di idee sull'Antropocene, il concetto secondo cui gli esseri umani ora guidano gran parte della geologia sulla superficie della Terra, e presiede il Gruppo di lavoro sull'Antropocene della Commissione Internazionale sulla Stratigrafia.

Skeletons: The Frame of Life pdf da Jan Zalasiewicz

Over half a billion years ago life on earth took an incredible step in evolution, when animals learned to build skeletons. Using many different materials, from calcium carbonate and phosphate, and even silica, to make shell and bone, they started creating the support structures that are now critical to most living forms, providing rigidity and strength. Manifesting in a vast variety of forms, they provided the framework for sophisticated networks of life that fashioned the evolution of Earth's oceans, land, and atmosphere. Within a few tens of millions of years, all of the major types of skeleton had appeared. Skeletons enabled an unprecedented array of bodies to evolve, from the tiniest seed shrimp to the gigantic dinosaurs and blue whales. The earliest bacterial colonies constructed large rigid structures - stromatolites - built up by trapping layers of sediment, while the mega-skeleton that is the Great Barrier Reef is big enough to be visible from space. The skeletons of millions of coccolithophores that lived in the shallow seas of the Mesozoic built the white cliffs of Dover. These, and insects, put their scaffolding on the outside, as an exoskeleton, while vertebrates have endoskeletons. Plants use tubes of dead tissue for rigidity and transport of liquids - which in the case of tall trees need to be strong enough to extend 100 m or more from the ground. Others simply stitch together a coating from mineral grains on the seabed. In Skeletons, Jan Zalasiewicz and Mark Williams explore the incredible variety of the skeleton innovations that have enabled life to expand into a wide range of niches and lifestyles on the planet. Discussing the impact of climate change, which puts the formation of some kinds of skeleton at risk, they also consider future skeletons, including the possibility that we might increasingly incorporate metal and plastic elements into our own, as well as the possible materials for skeleton building on other planets. Table of contents :