Tuesday January 8, 2013 (Indirect Fossil Evidence; Index Fossils)

The Launch Pad Tuesday, 1/8/13 List the eight general types of fossils. Direct - teeth, bones, shells Direct - mummified fossils Direct - amber-preservation fossils Modified - petrified fossils Modified - replacement fossils Modified - mold and cast fossils Modified - carbonization fossils Modified - impression fossils

The Launch Pad Tuesday, 1/8/13 Which of the following are probably not fossils?

Announcements Happy Bubble Bath Day!

Announcements I will be available after school today until 4:45.

Assignment Currently Open Summative or Formative? Date IssuedDate Due Date Into GradeSpeed Final Day Quiz 14S412/12 12/191/16

Recent Events in Science First Fossil Bird With Teeth Specialized for Tough Diet Read All About It! 3/01/ htm Beak shape variation in Darwin's finches is a classic example of evolutionary adaptation, with beaks that vary widely in proportions and shape, reflecting a diversity of ecologies. While living birds have a beak to manipulate their food, their fossil bird ancestors had teeth. Now a new fossil discovery shows some fossil birds evolved teeth adapted for specialized diets. A study of the teeth of a new species of early bird, Sulcavis geeorum, published in the latest issue of theJournal of Vertebrate Paleontology, suggests this fossil bird had a durophagous diet, meaning the bird's teeth were capable of eating prey with hard exoskeletons like insects or crabs. The researchers believe the teeth of the new specimen greatly increase the known diversity of tooth shape in early birds, and hints at previously unrecognized ecological diversity. Photograph of Sulcavis geeorum skull, a fossil bird from the Early Cretaceous (120 million-years-ago) of Liaoning Province, China with scale bar in millimeters. (Credit: Photograph by Stephanie Abramowicz)

Certain conditions favor fossil preservation. Rapid burial by silt or organic matter Possession of hard parts Fossils - Evidence of Past Life

Indirect Fossil Evidence Tracks – animal footprints made in soft sediment that was later lithified.

Fossils - Evidence of Past Life Indirect Fossil Evidence Burrows

Fossils - Evidence of Past Life Indirect Fossil Evidence Coprolites – fossil dung and stomach contents

Figure 11.13F

Fossils - Evidence of Past Life Indirect Fossil Evidence Gastroliths – stomach stones used to grind food by some extinct reptiles

Fossils and Correlation The Principle of Fossil Succession was first proposed by William Smith in the late 1700s. This principle states that fossils succeed one another in a definite and determinable order. Fossils - Evidence of Past Life

Determining the Ages of Rocks Using Fossils Figure 11.14

Fossils and Correlation Index Fossils Index fossils are fossils used to define and identify geologic periods. They work on the premise that, although different sediments may look different depending on the conditions under which they were laid down, they may include the remains of the same species of fossil. Fossils - Evidence of Past Life

Fossils and Correlation Index Fossils If the species concerned were short-lived (in geological terms, lasting a few hundred thousand years), then it is certain that the sediments in question were deposited within that narrow time period. The shorter the lifespan of a species, the more precisely different sediments can be correlated, and so rapidly evolving types of fossils are particularly valuable. The best index fossils are common, easy-to-identify at species level, and have a broad distribution - otherwise the likelihood of finding and recognizing one in the two sediments is minor. Fossils - Evidence of Past Life

What is a Fossil? Crossword