2009 Fossil notes Div B

Transcription

1 The Objectives of this event are to: 2009 Fossil notes Div B 1. Create the motivation and interest in the pursuit of the earth sciences. 2. Understand the identity of fossils and the process of fossilization. 3. Practice the ability to observe! 4. Learn to respect the delicate nature of the fossils. Fossil Information: A Fossil is: the remains or traces of animals or plants preserved in the Earth s crust by natural causes. What you need to be a fossil: (1) Quick burial - retard decomposition by bacteria (mud, ash, resin, low temperature, dry air). (2) Hard parts. (3) Time. Best place to become a Fossil: (1) Continental Shelf. (2) Swamp. (3) Lake or Riverbed or shore. Marine animals have a better chance to become a fossil. Types of Fossils: Unaltered Soft Parts: hair, skin, etc. Trapped in Amber: fossil resin or tree sap Trapped in Tar: LaBrea Tar Pit, Insects to large Pleistocene mammals Frozen: Siberia, mammoths 10,000 Years ago Desiccated or Mummified: Dry areas, - mummies, Mongolia, China - Dinosaur eggs Unaltered Hard Parts: shells and sponges Calcite - coral, clam, scallop, etc. secrete shells of calcite Silica - opal, sponge spicules, flagellates radiolarian Chitin - shells of arthropods, graptolites Altered Hard Parts: Carbonization: Carbon thin film of plants, fish, graptolites, arthropods Permineralization: water deposits minerals in porous bones and shells Silicification: petrified wood Phosphatization: bones & teeth

2 Limestone Tomb Recrystllization: molecules rearranged in crystal aggregates by solution and precipitation - original structure distorted Replacement: Substitute one Ion for another Pyritization or Pyrite for Calcite Calcite for Silica Silica for Calcite Trace Fossils: Footprints - Dinosaurs Worm Burrows Coprolite - fossil feces Molds cavity- depressions made by shells, etc. Casts - the filling of a mold Since no two fossils are identical and they are the result of, heating, pressing, and Decaying a lot of imagination is necessary to identify fossils. Identification is not absolute and many fossils go through many name changes over the years. It is recommended that the best fossils available be presented in the competitions. Some of the fossils may be worth hundreds of dollars and we would appreciate the students understanding that they will be viewing and examining some rare specimens. We will limit the identification of life forms to those on the list. The identification of fossil forms will not be limited to those on the list. The identification of the dinosaurs will be from pictures, skeletal models, descriptions, and bone fragment fossils. Be aware of fossils in the NEWS! We expect students to be able to use the following tools (which will be supplied at the events), Hand Lens, Jewelers Loop, Magnifying Lens, and a simple Microscope to view Microfossils. The microscopes will be used to identify Diatoms and calcite exoskeletons. Students should be aware of the relationship of oxygen and carbon dioxide in plants vs. animals. We will be looking at the rock types that fossils can be found in. Four locations in North America dominate the collection of the author: Mazon Creek, IL an outcropping of Pennsylvanian Plants and Animals. The state of Maryland, an outcropping of Miocene Period Fossils. Arkona, Ontario, Canada The shale deposits of a receding glacier. Gateway Country, Alberta Canada Home of Dinosaur National Park. Coaching Resources:

3 Earth Science Educators Supply, (E.S.E.S.) P.O. Box 503, Lee s Summit, MO (816) offers CA14 a set of 30 fossils for $16 which is an inexpensive set to study from, for this event. It is recommended that event supervisors use a minimum of the CFD-25 Fossil Display Set for the actual event, also available from E.S.E.S. Three books can used to study for this event: Rhodes, Zim, and Shaffer, Fossils, A Golden Guide -- Excellent text in an easy to read format on fossils. Cyril Walker & David Ward, Smithsonian Handbook to fossils-- Excellent text in a format students like. Sample websites: * * * or Phylum: Arthropoda Class: Trilobita Common Name or Members: trilobites Periods of Existence: Lower Cambrian through Permian Description: Trilobites are named for the three longitudinal lobes of their bodies. A raised middle lobe begins at the head and runs down into the tail, and a flatter lobe is present at each side of the middle one. The trilobite body is also divided into three sections: the head, the thorax and the tail. Since it was not calcified, the underside of the trilobite skeleton was never preserved. Many trilobite fossils are internal molds of the dorsal skeleton. Cryptolithus

4 Phacops Elrathia Isotelus Phylum: Bryozoa Common Name or Members: moss Animals Periods of Existence: Ordovician to Recent: possibly also Upper Cambrian Description: All are colonial, but their colonies are usually small. Bryozoans may be encrusting, massive, branching, or sheet like.

5 Rhomboporia ARCHIMEDES Phylum: Brachiopoda Common Name or Members: brachiopods Habitat: All are marine Periods of Existence: Cambrian to Recent Description: All brachiopods have a shell with two valves. Each valve is a mirror image of the other. When the valves of a brachiopod are closed, its form is often eggshaped or flat. The ventral valve is usually larger than the dorsal valve and extends farther beyond the hinge. An articulate brachiopod is one with a moveable connection between its valves. An inarticulate brachiopod relies upon muscles to hold its valves together.

6 Lingula Atrypa Mucrospirifer

7 Platystrophia Rafinesquina Leptaena

8 Composita Juresania Phylum: Cnidaria Class: Anthozoa Subclass: Rugosa Common Name or Members: tetracorals, horn corals and cup corals Habitat: With few exceptions, cnidarians are marine. Periods of Existence: Ordovician through Permian Description: Rugosa are usually large and may be solitary or colonial with a solid external skeleton. Their basic shape is that of an inverted cone. Solitary rouge corals are curved or erect and can be short and wide or tall and cylindrical. Heliophyllus

9 Favosites Halysites Septastraea Hexagonara

10 Phylum: Cnidaria Class: Anthozoa Subclass: Tabulata Common name or Members: tabulate coral or honeycomb coral Periods of Existence: Ordovician through Permian Description: Tabulates are a strictly Paleozoic group. Tabulates are characterized by inconspicuous septa and well-developed horizontal platforms under the calices. The platforms are usually straight and complete. All tabulates are colonial. Their coralites are typically long, straight, slender tubes and may be elliptical, circular or polygonal in cross section. The walls of the tubes may have pores. Tabulata Phylum: Echinodermata Class: Blastoidea Common Name or members: blastoid Habitat: all were marine Periods of Existence: Silurian through Permian Description: Blastoids were small, stemmed echinoderms that lived attached to the sea floor. Their heads, or thecas, are covered by regularly arranged plates and are usually the only part of the creature that was preserved. An area containing a shape resembling five petals extends downward from the mouth located neat the center of the upper side of the theca. Blastoid Pentremites

11 Phylum: Echinodermata Class: Crinoidea Common Name or members: crinoid stems Habitat: all were marine Periods of Existence: Lower Ordovician to Recent Description: Most crinoid fossils are formed only from the stems of crinoids. These stems have been broken into discs, which are usually round but may be elliptical or five sided. The flat part of the disc is covered with radiating grooves and ridges that may extend from the hole to periphery or may cover only part of the surface. Stems Stem peices Cronid Fronds Phylum: Echinodermata Class: Echinoidea Common Name or members: sea urchins, sand dollars and heart urchins Habitat: all were marine. Periods of Existence: Ordovician to Recent Description: Echinoids are globular or disc-shaped. Primitive echinoids display fivepart symmetry. The shell consists of small, thin, interlocking plates that are polygonal

12 in shape. These plates are arranged in ten narrow bands radiating from the top of the shell around to the mouth on the bottom. Five of the bands contain plates with holes or slits from which the tube feet project. These may form a five-petalled flower pattern on top of the shell. Alternating bands contain plates without such holes. Sand dollars Heart urchins Sea urchins

13 Phylum: Mollusca Class: Bivalvia Common Name or members: clams cockles, mussels, oysters and scallops Habitat: Most are marine, but some are common in lakes and streams. Periods of Existence: Cambrian to Recent Description: Almost all bivalves have shells composed of two parts called valves. The dorsal side of the animal is at the hinge line, and the ventral side is down. This is Gryphaea typically thick and solid, and is composed either of aragonite or calcite, or a mixture of both. Pecten Gryphaea Exogyra

14 Pholadomya Phylum: Mollusca Class: Cephalopoda Common Name or members: squids, cuttlefish, octopods, and nautilus Periods of Existence: Upper Cambrian to Recent Description: The first fossil cephalopods had straight shells. Fossil cephalopods may have concentric ribs and longitudinal lines, ribs or bumps. Orthoceras Nautilus

15 Dactylioceras Baculites Belemnites Ammonite Phylum: Echinodermata Class: Asteroids Common Name or members: sea stars Habitat: all were marine. Periods of Existence: Ordovician to Recent

16 Description: Sea stars are radially symmetrical, and their arms are arranged around a central disk. Most species have five arms, however sun stars can have as many as 40 arms or more! Most sea stars are small usually measuring cm across, but there are some species that can be very small or very large. Phylum: Echinodermata Class: Ophiuroidea Common Name or members: brittle stars Habitat: all were marine. Periods of Existence: Ordovician to Recent Description: Sea stars are radially symmetrical, and their arms are arranged around a small central disk. Most species have five arms, brittle stars have long, flexible arms (hence the other common name for ophiuroids, "snake stars" and a central, armored, disk-shaped body that is clearly demarcated from the arms. The body and arms are also protected by calcium carbonate plates, and the arms generally bear delicate spines.

17 Phylum: Mollusca Class: Gastropoda Common Name or members: snails, nudibranchs, sea hares and garden slugs Periods of Existence: Cambrian to Recent Description: Many gastropod shells, especially from the Paleozoic, are preserved as internal or external molds, or as casts. The typical gastropod shell is a long, narrow cone coiled into a disc or, more often, a spire with an opening at the bottom. Each complete turn of the coil is called a whorl. Conus Turnitella Worthenia

18 Platyceras Cypraea Phylum: Porifera Common Name or members: sponges Habitat: Sponges are almost entirely marine, but may be found in sand and mud. Periods of Existence: Upper Proterzoic [of the Precambrian] to Recent Description: Sponges have an internal skeleton usually composed of needlelike, mineralized spicules and spongin, a fibrous, horny substance. The only sponges likely to be preserved are those whose spicules have been fused into a rigid framework. A few of these forms are fairly common in Paleozoic rocks. Hydnoceras

19 Astraeospongia Phylum: Foraminifera Common Name or members: Habitat: Sponges are almost entirely marine, but may be found in sand and mud. Periods of Existence: Upper Proterzoic [of the Precambrian] to Recent Description: Nummulites Fusulinid Triticites

20 Diatoms These algae hardly look like plants, but more like flying saucers, tiny canoes or cigars, lobed leaves, the undersides of mushroom caps, striated ribbons, or filigreed Christmas ornaments. Whatever their shape, all diatoms have shell-like, brittle cell walls made out of silica (glass) and pectin. The walls are two interlocking halves or shells that fit together like a pillbox. Because they depend on sunlight for photosynthesis, diatoms generally live in the upper 200 meters of oceans and bodies of fresh water. Phylum: Graptolithina Common Name or members: graptolite Periods of Existence: Cambrian to Carboni-ferous Description: Very intricate shapes are formed by these colonies of organisms. Very unique fossils. Ggraptolite

21 Phylum: Arthropoda Subphylum: Crustaca Common Name or members: Shrimp, Lobsters, Crabs, Barnacles Periods of Existence: Cambrian to Recent Description: A group united by their characteristic bilateral symmetry and segmented, hard outer skeleton (exoskeleton). Crustaceans which include shrimps, crabs and lobsters are members of a special group of arthropods called Decapoda. All have 5 pairs of legs with one or more pairs equipped with a Pincer Shrimp. Lobster Crab

22 Horseshoe crab Barnacles Balanus Trace Fossils Trails, Borings Trilobite Trails Borings

23 Tracks, Trackways Dinosaur Footprint Dinosaur Trackway Burrows Worn Burrow Cast

24 Coprolites Herbivore Carnivore Coprolites Other Fossils Trapped in amber Trapped in tar

25 Petrified wood Stromatolites Eurypterids Insects

26 Also see: trapped in amber & Trapped in tar Dragonfly