منابع مشابه
Biological extinction in earth history.
Virtually all plant and animal species that have ever lived on the earth are extinct. For this reason alone, extinction must play an important role in the evolution of life. The five largest mass extinctions of the past 600 million years are of greatest interest, but there is also a spectrum of smaller events, many of which indicate biological systems in profound stress. Extinction may be ep...
متن کاملOphiolites and Their Origins
Ophiolites are the remnants of ancient oceanic crust and upper mantle that were tectonically emplaced into continental margins. They display the only evidence for magmatic, tectonic, and hydrothermal processes associated with seafl oor spreading prior to 170 Ma because no oceanic lithosphere older than this age is preserved in the modern oceans. The occurrence of sheeted dikes, side-byside tabu...
متن کاملHistory of life on Earth
“We’re related to the grass”, our biology teacher once proclaimed in his South Tyrolean accent that was at the same time unmistakable and highly liable to impersonation. Our 14-year-old, hormone-clouded minds can perhaps be forgiven for not immediately fathoming the profound scientifi c truth behind this statement, but looking back now, it stuck as poignant way of encapsulating what is perhaps ...
متن کاملBiological versatility and earth history.
Examples from various plant and animal groups indicate that there has been a general increase in potential versatility of form, determined by the number and range of independently varying morphogenetic parameters, among taxa appearing at successively younger stages in the fossil record. Taxa or body plans with higher potential versatility have tended to replace less potentially versatile groups...
متن کاملOxygen and animals in Earth history.
In the annals of Earth history, few associations have proven more iconic or durable than that between animals and oxygen. As early as 1919, the experimental physiologist August Krogh (1) explored the relationship between O2 and animal anatomy, and 40 y later J. R. Nursall (2) posited explicitly that metazoans appear as fossils only in uppermost Proterozoic rocks because pO2 was insufficient to ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Eos, Transactions American Geophysical Union
سال: 2004
ISSN: 0096-3941
DOI: 10.1029/2004eo440009