A definition of "Science"

So just what is science?

The dictionary explains that the word comes from the Latin “scientia” meaning “knowledge”, but there are different kinds of knowledge and different ways of accumulating knowledge. Science is the branch of knowledge built on observations of the natural world systematically arranged to reveal patterns. Scientists seek to discover and document these patterns and ultimately understand their underlying causes.

The purpose of science is to understand, explain, and to predict natural phenomena, it is not the purpose of science to judge, rank, or otherwise assign value to the phenomena—that’s the role of other ways of understanding the world, the role of philosophy, the arts, and religion.

Science is best suited to answer the “who, what, where” sorts of questions; the other paths of inquiry are better suited to answer questions related to the ultimate purpose of things.

Photo credit: http://undsci.berkeley.edu/images/us101/scientists.jpg

Nature of science, 1

Sixty-six percent of adults in a USA Today/Gallup Poll* responded with “definitely” or “probably true” to the statement that “God created human beings pretty much in their present form at one time within the last 10,000 years”.

Of course, this explanation is not taught in science classes because it is a conclusion that is not based on science but a religious text. The pervasiveness of this erroneous viewpoint points to a fundamental confusion in the minds of many people about what science is and how it works, the areas of human experience that science can and cannot address, and a perceived conflict between the findings of science and personally held beliefs.

So just what is science and what does it do? Continued tomorrow...

*http://www.pollingreport.com/science.htm

photo credit: http://imagecache2.allposters.com/images/pic/MCG/FPF631~Adam-and-Eve-Posters.jpg

When a "theory" isn't a theory

Many non-scientists use the words“hypothesis” and “theory” interchangeably (if they use ‘hypothesis” at all) and as synonyms for “idea.”

To a scientist, hypotheses are much more than an idea, much more than an “educated guess”; they are possible explanations based on numerous and repeatable observations (data). In the hierarchy of the scientific method, a theory is an even stronger statement than hypothesis.

The American Association for the Advancement of Science (AAAS), the top scientific society in the United States, defines “theory” as “a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment. Hypotheses and theories may begin as a bright idea, but they are so much more.

*(http://www.aaas.org/news/press_room/evolution/qanda.shtml accessed 3-25-10)

photo credit: http://www.dreamstime.com/stock-images-dreamstime-download-free-stock-images-and-photos-image1940874

Nature of Science, 2

So just what is science?

The dictionary explains that the word comes from the Latin “scientia” meaning “knowledge”, but there are different kinds of knowledge and different ways of accumulating knowledge. Science is the branch of knowledge built on observations of the natural world systematically arranged to reveal patterns. Scientists seek to discover and document these patterns and ultimately understand their underlying causes.

The purpose of science is to understand, explain, and to predict natural phenomena, it is not the purpose of science to judge, rank, or otherwise assign value to the phenomena—that’s the role of other ways of understanding the world, the role of philosophy, the arts, and religion.

Science is best suited to answer the “who, what, where” sorts of questions; the other paths of inquiry are better suited to answer questions related to the ultimate purpose of things.

Photo credit: http://undsci.berkeley.edu/images/us101/scientists.jpg

Getting batty

Many modern bats use echolocation to help navigate and capture prey in flight. Most echolocating bats produce the signal in their larynx, but a few species create echolocation sounds by tongue clicks, and other bats do not echolocate at all.

Scientists used CT scans to study the articulation of the ear bones in modern bats and found that the bats that use echolocation produced from the larynx have a distinctive articulation of the stylohyal bone with the tympanic bone not seen in the bats that do not echolocate or that use tongue clicks.

In other words, the ability to produce echolocation using the larynx is recorded in the skeletal structure of bats, and this makes it possible to look for this feature in fossil bats.

The oldest known fossil bat appears to have this distinctive articulation but a conclusive answer awaits more fossil finds.

First dino from Bulgaria

When it comes to dinosaurs, North America, China, and South America have decided advantages over other countries—they are large and have vast quantities of sedimentary rock deposited in ancient river or floodplain environments during the Mesozoic Era, the age of dinosaurs.

Recently the first dinosaur fossil from Bulgaria was described. It’s no Sue, the most complete T. rex ever found, but a single bone 10 cm long and 5 cm wide interpreted as the left humerous—the upper bone in the forelimb--of a Late Cretaceous Theropod—a European cousin to Sue.

The bone was found in limestone—a sedimentary rock usually deposited in a marine environment, but the isotopic signature of the bone differs from that of the limestone, indicating that the bone was probably transported into the shallow sea after burial and fossilization.

Source: MATEUS, OCTÁVIO; DYKE, GARETH J.; MOTCHUROVA-DEKOVA, NEDA; KAMENOV, GEORGE D.; IVANOV, PLAMEN. The first record of a dinosaur from Bulgaria. Lethaia, Volume 43, Number 1, March 2010 , pp. 88-94(7)

Carving up dino ecospace

Ecological theory explains that in order for more than one predator species to thrive in an ecosystem, the different species must occupy different niches, or roles, in the ecosystem.

Paleontologists have discovered an example of niche partitioning among different types of carnivorous dinosaurs: tyrannosaurs--the group that includes T. rex--and their sail-back cousins, the spinosaurs. Researchers analyzed the isotopic signature of spinosaur and tyrannosaur teeth and found that the oxygen isotope ratio of spinosaurs is lower than that of other theropods living in the same area at the same time.

The lower spinosaur ratio is a closer match to that of fossilized crocodiles and turtles from the same area. This match suggests that spinosaurs spent most of their time in or around aquatic habitats, a niche not occupied by the tyrannosaurs.

Source: Science News March 13, 2010, p. 18

Amiot, R., et al., Geology February, 2010

The search for earliest life, continued

Identifying traces of life in very ancient rocks is understandably difficult, and more than one claim for the oldest evidence of life later has not withstood scrutiny after making its initial splash in the headlines or even after being incorporated into textbooks. Tiny structures initially identified as microfossils have been reinterpreted to be the result of inorganic rather than organic processes.

A recent discovery, however, offers convincing evidence for the presence of relatively large, organic-walled microfossils in rocks 3.2 billion years old from South Africa. The structures are interpreted as organic on the basis of their cell-like morphology and ultrastructure, the fact that they occur in large numbers, as would microfossils, and their presence in rocks that represent environments that would have been amenable to living organisms. Time will tell.

Source and photo credit: Javaux, E.J., et al., 2010. Organic-walled microfossils in 3.2-billion-year-old shallow-marine silicilastic deposits. Nature 463:934-938.

Snake v. dinosaur

It sounds like a B-movie plot, but paleontologist found a 67-million-year old fossilized snake lurking among fossilized sauropod dinosaur eggs in a posture that suggests the snake was preying on the hatchlings.

The 11-foot-long-snake was coiled around a broken eggshell with a fossil dinosaur hatchling nearby. The fossils were from a locality in India known for abundant dinosaur eggs that may have been a sauropod nesting ground.

The sauropods dinosaurs excavated a shallow depression and laid their clutch of 6 to 12 eggs, and probably covered the eggs with soil or vegetation and left the eggs to hatch, as do modern reptiles like sea turtles. Predators would be drawn to this bounty of prey, but in this case, both predator and prey were buried alive by a sudden avalanche of sediment. It’s a single moment, frozen in time.

“Predation upon Hatchling Dinosaurs by a New Snake from the Late Cretaceous of India,”/Jeffrey A. Wilson, Dhananjay M. Mohabey, Shanan E. Peters, Jason J. Head/Public Library of Science Biology, Mar. 2010, Vol. 8, Issue 3.

Triassic dinosaurs

The earliest dinosaurs are known from the Late Triassic Period of the Mesozoic Era, about 230 million years ago.

By the end of the Triassic Period, the three major groups of dinosaurs had appeared, the theropods, carnivorous dinosaurs that would later include T. rex; the sauropods, which would come to include the huge plant-eaters of the Jurassic Period, and the ornithischians, smaller, more lightly built dinosaurs.

The fossil record of Triassic dinosaurs is poor relative to the Jurassic and Cretaceous Periods, comprising largely fragmentary and incomplete material, so the discovery of several nearly complete skeletons of a new Late Triassic theropod dinosaur from New Mexico is an important contribution to understanding the early evolution of the dinosaurs and helps to clarify the relationships among other Triassic dinosaurs.

Sources:

http://www.nsf.gov/news/special_reports/tawa/index.jsp

http://www.universityofcalifornia.edu/everyday/pscience/dinosaurs.html

An egg-celent discovery

Every now and then an exceptionally preserved fossil sheds light on the biology of an extinct organism.

One such specimen was the remains of a dinosaur from Cretaceous sedimentary rocks in China. The pelvic area of the dinosaur contains two 17-cm long, potato shaped eggs that were ready to be laid when the dinosaur died.

The two eggs fill the pelvic cavity and are similar in size, suggesting that the dinosaur had two oviducts that simultaneously produced one egg each. Modern reptiles like sea turtles, have two oviducts, but produce multiple eggs; birds have single oviducts and produce only one egg at a time.

The egg-laying behavior of the Chinese combines elements seen in both these modern groups, evidence of a common ancestry in the geologic past.

Science, April 15, 2005. Tamaki Sato. Photo from the article

Archaeopteryx brain scan

Modern medical technology has made it possible to study old anatomies.

Computerized tomography, or CT scanning can be used on fossils to study their internal structure. CT scans of the brain case of an Archaeopteryx skull shows that this transitional form between reptiles and birds had a brain region associated with vision that made up almost 1/3 of the brain’s volume.

The lobes associated with hearing and muscle coordination were also well-developed. The ratio of brain volume to body mass is higher than that associated with modern reptiles but a bit less than that for modern birds, more evidence for the intermediate position Archaeopteryx occupies between birds and reptiles.

CT scans also showed that the structure of the inner ear of Archaeopteryx more closely resembles tat of modern birds than reptiles.

In sum, it appears that Archaeopteryx had well developed senses of hearing, balance, and sight, traits that support the hypothesis that Archaeopteryx was capable of flight.

The photo is from http://digimorph.org/specimens/Archaeopteryx_lithographica/ check it out to rotate it and examine the skull from other angles.

Sources:

Science News Aug. 7, 2004, p. 166

Timothy B. Rowe, Nature, August 5, 2004

Early bird hatchlings got their own worms

A 121-million-year-old fossilized bird embryo from China provides evidence that at some ancient chicks were able to care for themselves after hatching.

The China fossil bird is well-ossified, with nearly complete feathers and a large skull, indicating that the hatchling was able to walk and feed independently upon hatching.

Younger fossil bird embryos from 75 million-year old rocks in Argentina do not have feathers preserved. The difference between the China and Argentina embryos might indicate an evolutionary trend in hatchlings, from precocial to altricial in that 45 million year time span, or it may reflect preservation differences; Argentina embryos may have been at an earlier stage of development or had feathers that were not preserved.

It will take a few more discoveries of well-preserved fossil hatchlings to confirm the hypothesis.

Sources:

Science News 23 Oct. 2004, p. 166

Science Oct. 22, 2004 Zhonge Zhou and f.Zhang

Irish Elk, revisited

The Irish Elk has long stood in textbooks as an icon for ice-age extinction.

The giant deer with the massive 12-foot-wide rack was thought to be extinct by the end of the last ice age; the most recent fossils of the Irish Elk had been dated to 12,000 years ago, but new discoveries in Siberia show that the Irish Elk was living there until about 7,000 years ago….4,000 years later than previous fossil finds indicated.

This new information implies that the extinction of the Irish Elk was not as abrupt as previously thought, and will add to the ongoing discussion of the factors that may have caused the extinction of the animal, climate change, disease, hunting.

Science News 6 November 2004, p. 34

See Nature, Oct. 7, 2004, Anthony J. Stuart.

Discovering Dinosaurs

If it seems that a new species of dinosaur is announced every other week, you are correct.

In recent years new finds in China and Argentina have doubled the number of dinosaurs known from those two countries. Over a 14-year period China added 52 new genera to its list of dinosaurs.

At this rate, are we in danger of running out of new dinosaurs to discover? The experts say no, based on an analysis of the locations the finds are coming from. There are still plenty of strata to explore, and good news for aspiring paleontologists, we have probably only scratched the surface of dinosaur diversity.

Photo credit: http://www.indiaonrent.com/forwards/d/dinosaurs-evolution/res/hd3szn.jpg

Science News 10 Nov. 2004, p. 334

Cute factor: Baby living fossil

“Living fossil” refers to a species that is geologically long-lived and at least outwardly little changed through its history. Horseshoe crabs, sharks, and ginkos are examples of living fossils.

One of the more interesting cases of living fossils is the coelocanth, a fish with lobe-like fins that was thought to be extinct, known only from fossils from the Devonian Period, until 1938 when a dead coelocanth turned up in a fisherman’s net off the coast of South Africa. Since then there have been several live coelocanth sightings, but studying them is difficult because of their deep-water habit.

New technology helps: a robotic submersible filmed the first ever observed living baby coelocanth off Indonesia (photo)

You are what you poop

Not the most delicate way to put it, but true, as some paleontological sleuthing shows...

Scientists went prospecting along Alaska’s Yukon River, not for gold, but for soil samples in the permafrost looking for DNA from the urine and feces of ice-age mammals.

They struck it rich, and identified DNA from mammoth, bison, moose, horse, and snow shoe hare. The mammoth and horse DNA came from sedimentary layers about 10,000 years old—that is more recent than the youngest known fossil bones of these animals by at least 300 years.

The permafrost DNA implies that these species survived longer than originally presumed on the basis of the skeletal fossil remains, and indicates that the ice-age extinction of large mammals in North America was not a sudden event as previously thought.

Photo credit and more info: http://www.physorg.com/news180095166.html