Paleontology is the study of fossils, which are defined as the remains or other
evidence of the life of past geologic ages. Fossils are found in sedimentary rocks
that occur in layers. Since newer layers are laid down on top of older ones, the layered rocks
can be used to establish a scale of geologic time. Strata from different locations can
be judged to be contemporaneous if they contain many similar fossils (correlation by fossils).
The study of fossilization as a process is called taphonomy.
The scientific study of classifications is called Taxonomy. Taxonomists often
use Cladistics to draw up family trees (phylogenies) first and then base classifications
on them. A group is considered monophyletic is it contains a common ancestor and all of its
descendents. The Phylum Chordata is a monophyletic group containing organisms that share a
notochord, a dorsal, hollow nerve cord, and a series of gill slits. The
Vertebrata are a subphylum of chordates in which the notochord is functionally replaced in
adult animals by a backbone or vertebral column.
- Paleontology: The study of Fossils
Fossils are the remains (or other evidence) of life
of past geologic ages.
Types of fossil preservation
- Sedimentary rocks
- Geologic time
Geologic time
- Vertebrate history through time
- Phylum Chordata:
- Embryological similarities to Echinoderms (starfishes, crinoids, etc.)
- Acorn worms and pterobranchs (Hemichordata)
- Subphylum Urochordata: Sea squirts
- Subphylum Cephalochordata: Amphioxus; Pikaia
- Subphylum Vertebrata
Illustrations
- Bones, cartilage, and teeth
- About classification (taxonomy) and cladistics
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