When climate twitches, evolution takes great leaps

Journal Article · Fri Sep 18 04:00:00 EDT 1992 · Science (Washington, D.C.); (United States)

DOI:https://doi.org/10.1126/science.256.5064.1622-a· OSTI ID:6955476

Kerr, R A

Earth's climate system has ridden a slow roller coaster for the past 60 million years. It warmed gradually until about 53 million years ago, reaching a peak that brought crocodiles to northern Canada; then it entered a long, undulating downgrade toward the ice-age world of the past few million years. Because the same span of time brought major evolutionary changes, including the rise of modern mammals, paleontologists have long assumed that these slow temperature changes helped spur the processes of evolution. But recent findings have suggested that another, more potent mechanisms was also at work: Abrupt climate excursions, superimposed on these long-term trends, have now been linked to rapid periods of mammal evolution. The evidence for short, sharp evolutionary shocks comes from studies of a pair of mirror-image climate shifts at opposite ends of the Eocene epoch, 55 million and 33.5 million years ago. In both cases, researchers studying the record of climate preserved in sea-floor sediments have found that a gradual climate change-warming in the first case, cooling in the second - suddenly steepened into a short-lived pulse of extreme warming or cooling. The short time scale of these events and their clear coincidence with turning points in the evolution of mammals are providing the tightest links yet between global climate change and evolution on land.

• OSTI ID: 6955476
• Journal Information: Science (Washington, D.C.); (United States), Journal Name: Science (Washington, D.C.); (United States) Vol. 257:5077; ISSN SCIEA; ISSN 0036-8075
• Country of Publication: United States
• Language: English

Related Subjects

29 ENERGY PLANNING, POLICY, AND ECONOMY
290301 -- Energy Planning & Policy-- Environment
Health
& Safety-- Regional & Global Environmental Aspects-- (1992-)
54 ENVIRONMENTAL SCIENCES
540110*
ANIMALS
BIOLOGICAL EVOLUTION
CENOZOIC ERA
CLIMATIC CHANGE
EOCENE EPOCH
GEOLOGIC AGES
MAMMALS
PALEOCLIMATOLOGY
PALEONTOLOGY
SEDIMENTS
TERTIARY PERIOD
VERTEBRATES