Historical Geology - Part II - Hooked on Fossils

Taxonomic Classification of Life on Earth

The hierarchy of taxonomic groups is

Kingdom : Phylum : Class : Order : Family : Genus : Species

Many biologists remember this by the sentence "King Philip cries out for great soup!"

Older classification system divided all things into five kingdoms:

1. Protista -- yellow-green and golden-brown algae and "protozoans"
2. Monera -- asexual unicellular microorganisms with no cell nucleus or other organelles
3. Fungi
4. Plants and
5. Animals.

I prefer an equally arbitrary system which proposes that all life be divided into three "domains" named

• Eubacteria -- "blue-green algae" cyanobacteria, purple sulfur bacteria and non-photosynthetic microbes.
• Archaebacteria -- thermophiles and methane-producing bacteria
• Eukaryota -- all other life forms.

From a historical geology perspective, we realize that not all groups are proportionally represented in the fossil record, so only some groups of living organisms are regularly used in historical geology. If you look up living organisms in biology books, you will find far more groups than are discussed in your text book.

The text admirably covers evolutionary concepts, paleogeography and other important topics, yet slights Kingdom Plantae and Domains Eubacteria and Archaebacteria. Visit the Virtual Museum "Bacteria Fossil Record" page for more information. Geochemists are probably the furthest along in their understanding of the influence of these two groups on earth. Some of these organisms may have contributed to the Earth's oxygen atmosphere. Cutting-edge work is being done in this area with applications to metals extraction and environmental remediation. Odd life forms like viruses are hardly even considered in the fossil record -- although we assume that they were equally common all the way back in time.

Abbreviated Classification of Life

1. Kingdom Plantae -- Botany Links
   If anything, plant taxonomy is more complicated than animal taxonomy. Here are just the highlights.
   • Cyanophyta -- blue-green algae
   • Chlorophyta -- green algae
   • Phaeophyta -- brown algae
   • Rhodophyta -- red algae
   • Bryophyta - liverworts, hornworts and mosses
   • Psilophyta - psilophytes
   • Lycopodophyta -- club mosses
   • Arthrophyta -- horsetails (Sphenopsida)
   • Pterophyta -- ferns (Filicineae)
   • Pteridospermophyta -- seed ferns
   • Spermatophyta -- seed bearers
     • Gymnosperms
       • Cycadophyta -- cycads
       • Ginkophyta -- ginkos
       • Coniferphyta -- conifers
     • Angiosperms - (Anthophyta) flowering plants
       • Class Dicotyledonae -- dicots
       • Class Monoctoyledonae -- monocots

2. Kingdom Animalia -- Fossil animal sites.
   • Phylum Protista -- single or groups of cells, forams, radiolarians, diatoms, coccolithophores and fusulinids
   • Phylum Porifera -- sponges
   • Phylum Archaeocyatha -- ancient reef builders, presumed extinct
   • Phylum Cnidaria -- corals (formerly Coelenterata), hydroids, sea anemones (Anthozoa) & jellyfish
   • Worms
     • Platyhelminthes -- flat worms
     • Nemertina -- ribbon worms
     • Trochelminthes -- rotifers and others
     • Annelida -- segmented worms
   • Phylum Brachiopoda -- brachiopods and lamp shells
   • Phylum Bryozoa -- moss animals
   • Phylum Echinodermata -- five-fold symmetry, starfish, brittle stars, sanddollars, echinoids, sea lilies, crinoids, blastoids, cystoids, sea cucumbers
   • Phylum Mollusca
     • Pelecypods - clams and oysters
     • Gastropods - snails, slugs
     • Scaphopods -- marine tube mollusks
     • Cephalopods - squid, octopus, nautiloids and ammonoids
   • Phylum Annelida - segmented worms and Scolecondonts
   • Phylum Arthropoda - segmented legs including insects, lobsters, crabs, trilobites, eurypterids
     • Trilobita -- trilobites
     • Crustacea -- crabs, lobsters, shrimp, crayfish, barnacles,
     • Arachnida -- spiders, mites, ticks, horseshoe "crab," eurypterids
     • Insecta -- insects and beetles
   • Phylum Problematica - Tullimonstrum, etc.
   • Phylum Hemichordata - acorn worms (graptolites)
   • Phylum Chordata - notochords and articulated backbones
     • Subphylum Unorchordata - tunicates and sea squirts
     • Subphylum Cephalochordates - amphioxus
     • Subphylum Vertebrata
       • Agnatha - hagfishes and lampreys
       • Placodermi -- extinct, fishlike with jaws
       • Chondrichthyes -- sharks, skates, rays, chimaeras and others with cartilage skeletons
       • Osteichthyes -- true bony fishes
         • Chondrosteans -- early bony fishes like sturgeons
         • Teleosts -- modern bony fishes
       • Amphibians - amphiuma, sirens, salamanders, frogs - Amphibian links.
       • Reptiles - lizards, snakes, turtles and crocodiles
       • Dinosaurs - ornithischia and saurischia -- Dinosaur links.
       • Birds
       • Mammals -- 33 orders/15 extinct (this is abbreviated)
         • Monotremes -- egg laying mammals -- duck-billed platypus
         • Multituberculates -- extinct in Eocene
         • Pantotheres -- shrew-like
         • Marsupials -- young suckle in pouch -- kangaroo, opossums
         • Placentals
           • Dermoptera -- bats
           • Primates -- lemurs, apes, monkeys, humans
           • Edentates -- ground sloths, armadillos, anteaters
           • Lagomorphs and rodents -- rabbits, rats, mice
           • Cetaceans -- whales, dolphins, porpoises
           • Carnivores -- dogs, cats, raccoons, weasels, civets, hyenas, bears
           • Ungulates -- cows, mammoths, mastodons, elephants, hippopotamuses, deer, giraffes, sheep, antelopes, sea cows, uintatheres (extinct)

Exercise:
Memorize, memorize, memorize!

Earthly Lifestyles

Lifestyles

• Autotrophs -- self-feeding
  • photosynthetic
  • thermophilic
  • chemical reactions
• Heterotrophs -- eat others
  • Omnivores -- eat all
  • Detrivores -- eat fallen material
  • Herbivores -- eat plants
  • Insectivores -- eat insects
  • Scavengers -- eat things previously dead
  • Carnivores -- kill/eat other animals

Exercise:
Play "match the lifestyle to the organism". Which pertain to plants, which to animals and within animals, be specific.

How to Become a Fossil - the process of Taphonomy

• Petrifaction of actual remains
  1. No alteration - frozen mammoths, La Brea tar pits, amber
  2. Chemical
     • permineralization -- precipitation into pores (Thornton Quarry)
     • recrystallization -- aragonite reverts to calcite, or changes in crystaline texture -- needs a microscope to see it
     • dissolution and replacement -- molecular exchange (Mazon Creek)
     • carbonization -- carbon films (graptolites, Green River Fish & Burgess Shale)
  3. Physical
     • molds -- external and internal ("steinkern")
     • casts -- mold void filled by minerals
  
  
• Petrifaction of Trace Fossils
  • tracks and trails must be filled quickly to be preserved
  • imprints can be made by wind blowing plant leaves or animals
  • gastroliths, "stomach-stones," are used by crocodiles, dinosaurs and birds (e.g. "canary grit")
  • bite marks and cut marks reveal the activity of one being on another
  • coprolites contain food items and microorganisms
  • bioturbation & burrows record feeding and resting
  • particular metal deposits (FeS2 crystals in chalk)

Agents of destruction and transport

• Biological agents -- scavengers and predators, bugs, beetles
• Mechanical agents -- wind, wave and ice
• Diagenesis and Discovery -- selective dissolution and metamorphosis, weathering, collecting for museums and private collections changes fossil composition

Areas of exceptional preservation include

• Upper Jurassic Solnhofen Limestone - Southern Germany - Archaeopteryx - specimens of "lithographic limestone" in our rock boxes are this type of material
• Pennsylvanian Mazon Creek Beds - Braidwood, IL - Please see the hallway cases and the scrap rock heap for specimens of this form of soft bodied preservation. Meet Andrew Hay, Christopher Ledvina and Charles Shabica of ESCI are all excellent resources for information on Mazon Creek siderite nodules.
• Middle Cambrian Burgess Shale, British Columbia, Canada - unique and bizarre fauna trapped in a turbidity current. Steven Jay Gould's book Wonderful Life and a rebuttal by Simon Conway-Morris, Crucible of Creation address evolutionary questions about the Burgess fauna.

Exercise:
Use the casting kit and casting cement, create carbonate fossil casts from "Skulduggery" or similar latex molds. Use casting cement, real fossils or trace fossils, and clear cello-wrap to create your own casts and molds. Walk through the sand tray and analyse your own trace fossils. Use plastic dinosaurs to create trackways in the sand tray. Describe the formation of siderite and how Mazon concretions may have formed.

Exercise 2:
Enter any more specific examples of taphonomic preservation in the table during the semester. Where did we see which type of preservation? And/or which type of preservation is found in famous fossil localities? Examples given include some from Mazon Creek and one from the Burgess Shale.

This section included the major field trip to downstate and western Illinois.

Visit my Homepage ©2008 by Ellin Beltz -- January 10, 2008