American paleontologist and evolutionary biologist at the University of Hawaii at Mānoa in the Department of Geology and Geophysics Dr. Stanley graduated Suma Cum Laude from Princeton University in 1963 with an AB, and earned his Ph.D. from Yale University in 1968. He is best known for his empirical research documenting the evolutionary process of punctuated equilibrium in the fossil record.
From 1969 to 2005, he taught geology at Johns Hopkins University, and has been a research professor at UH Mānoa since 2005. In 1972, Stanley developed the Predation Hypothesis to explain the evolution of novelties in the Cambrian explosion, proposing that predation stimulated prey animals to evolve defenses such as shells, rapid swimming, and burrowing.
Paleontology is the science dealing with the fossils of long-deceased animals and plants that lived up to billions of years ago. It's an interdisciplinary field involving geology, archaeology, chemistry, biology, archaeology and anthropology. Paleontology lies on the border between biology and geology, but differs from archaeology in that it excludes the study of anatomically modern humans. It now uses techniques drawn from a wide range of sciences, including biochemistry, mathematics, and engineering.
Use of all these techniques has enabled paleontologists to discover much of the evolutionary history of life, almost all the way back to when Earth became capable of supporting life, about 3.8 billion years ago. As knowledge has increased, paleontology has developed specialized sub-divisions, some of which focus on different types of fossil organisms while others study ecology and environmental history, such as ancient climates.
In 1977 Stanley was awarded the Paleontological Society's Charles Schuchert Award which is presented "to a person under 40 whose work reflects excellence and promise in the science of paleontology." In 2006 Stanley was awarded the Mary Clark Thompson Medal by the National Academy of Sciences. In 2007 he was awarded the Society's Paleontological Society Medal, which is "awarded to a person whose eminence is based on advancement of knowledge in paleontology’, and in 2008 he was awarded the William H. Twenhofel Medal by the Society for Sedimentary Geology.
Most recently, Dr. Stanley was the recipient of the 2013 Geological Society of America (GSA) Penrose Medal, the society’s highest honor. The Penrose Medal is considered one of the GSA's highest individual honors, awarded to one eminent researcher in pure geology each year. The Geological Society of America (GSA) is a global professional society with a growing membership of more than 25,000 individuals in 107 countries.
Stanley is known for his work employing fossil data to make a case for the punctuational model of evolution. This model holds that most species are generally stable, changing little for millions of years--then, most evolution is concentrated in brief events, when new species arise from others. Among many other contributions, Stanley has also shown that changes in seawater chemistry over the course of geologic time have influenced what kinds of marine organisms have flourished as major reef builders and limestone producers.
Stanley's book credits include best-selling textbook Earth System History as well as The New Evolutionary Timetable: Fossils, Genes, and the Origin of the Species, which was nominated for an American Book Award. He has been elected to the National Academy of Science (NAS) and the American Academy of Arts and Sciences.
Quotes by Steven M. Stanley, Phd
"I have been privileged to take part in two revolutions in paleontology," said Stanley. "The first, getting underway when I was a graduate student, was the injection of biology into paleontology on a large scale: paleontology expanded into paleobiology." -Steven M. Stanley, PhD
"In fact, my dissertation work dealt entirely with living animals, with the aim of bringing fossil creatures to life. No one questioned my motives, and my results were widely appreciated!" -Steven M. Stanley, PhD
March 2006, Pages 214-236
Although some organisms exercise considerable control over their biomineralization, seawater chemistry has affected skeletal secretion by many taxa. Secular changes in the magnesium / calcium ratio and absolute concentration of calcium in seawater, driven by changes in rates of deep-sea igneous activity, have influenced the precipitation of nonskeletal carbonates: low-Mg calcite forms when the ambient Mg / Ca molar ratio is < 1, high-Mg calcite forms when the ratio is 1–2, and high-Mg calcite and aragonite form when the ratio is above 2. Reef builders and other simple organisms that are highly productive biomineralizers have tended to respond to changes in seawater chemistry in ways that mirror patterns for nonskelatal carbonates. Also, changes in the concentration of silicic acid in seawater have affected the ability of organisms to secrete siliceous skeletons. In laboratory experiments, organisms that secrete high-Mg calcite in the modern aragonite sea incorporate progressively less Mg in their skeletons with a reduction in the ambient Mg / Ca ratio, producing low-Mg calcite in “Cretaceous” seawater (Mg / Ca molar ratio = 1.0). Because algae that liberate CO2 through calcification use it in their photosynthesis, an increase in the ambient Mg / Ca ratio results in accelerated aragonite secretion and overall growth for codiacean algae, and a decrease in the Mg / Ca ratio results in greatly accelerated growth rates for calcitic coccolithophores. Controlled experiments show that the increased concentration of Ca that accompanies a reduction of the ambient Mg / Ca ratio also accelerates coccolithophore population growth. Coccolithophores' production of vast chalk deposits in Late Cretaceous time can be attributed to the low Mg / Ca ratio and high Ca concentration in ambient seawater. The high Mg / Ca ratio and low Ca concentration in modern seawater apparently limit population growth for the large majority of modern coccolithophore species: ones that fail to respond to nitrate, phosphate or iron fertilization and are confined to oligotrophic waters. Presumably the low Mg / Ca ratio of ambient seawater was at least partly responsible for reduced reef-building by scleractinian corals in Late Cretaceous time. Some taxa have secreted more robust skeletons when seawater chemistry has favored their skeletal mineralogy. Strong intrinsic control of biomineralization can buffer a taxon against secular changes in seawater chemistry. Mollusks, for example, evolved the ability to severely limit the incorporation of Mg in their skeletal calcite in seawaters with Mg / Ca ratios as high as that of the present, but not in seawaters with still higher ratios. The ability to exclude Mg is useful because Mg reduces the rate of step growth of calcite crystals. On the other hand, labile skeletal mineralogy has permitted some taxa to respond to secular changes in the Mg / Ca ratio of seawater via phenotypic or evolutionary shifts of skeletal mineralogy. Sponges and bryozoans have apparently undergone evolutionary shifts of this kind polyphyletically. Increased incorporation of Mg in skeletal calcite with secular increases in the concentration of Mg in seawater has had little effect on seawater chemistry. In contrast, removal of Si by diatoms beginning in late Mesozoic time lowered the concentration of silicic acid in seawater, forcing siliceous sponges to secrete less robust skeletons.
Depressed rates of origination and extinction during the late Paleozoic ice age:
A new state for the global marine ecosystem
OCTOBER 01, 2003
Rates of origination and extinction for marine animal genera dropped to low levels in latest Mississippian time, immediately after massive glaciers formed in the Southern Hemisphere and a second-order mass extinction occurred. Evolutionary turnover and diversity remained low for ∼50 m.y., shifting markedly upward precisely when extensive glaciation ended in Early Permian time. All diverse taxa with good fossil records experienced low rates of origination and extinction during this major ice age. Such sluggish rates would be predicted for faunas of shallow seas on or adjacent to a heavily glaciated supercontinent such as Pangea, where cool and highly seasonal thermal regimes should dictate that species have broad ecological niches, widespread geographic distributions, and large and relatively stable populations.