Download presentation
Presentation is loading. Please wait.
1
What’s a fossil and how are they formed?
Fossilization What’s a fossil and how are they formed?
2
I. Fossilization A. The four types of fossils
1. mold fossils=a fossilized impression made in the substrate - a negative image of the organism.
3
2. cast fossils =formed when a mold is filled in.
4
3. trace fossils = fossilized nests,
gastroliths, burrows, footprints, etc. 1. Signs that a living thing was present 4. true form fossils = fossils of the actual animal or an animal part
5
B. True form and trace fossils
1. True form fossils a. Commonly come from hard parts of the body b. Bones-The fossilized bones of a tremendous number of species of dinosaurs have been found since 1818, when the first dinosaur bone was discovered.
6
c. Teeth and Claws- a broken tooth of a carnivore is found with another dinosaur's bones, especially those of herbivores. Lots of fossilized teeth have been found, including those of Albertosaurus and Iguanodon
7
d. Eggs Embryos and Nests-
1. first found in France in 1869 2. over 200 sites 3. nests and clutches of eggs tells much about dinosaurs' nurturing behavior
8
e. Skin 1. had thick, bumpy skin 2. A 12-year-old girl discovered a T. rex's bumpy skin imprint f. Muscles, Tendons, Organs, Blood Vessels 1. dinosaur "mummies", fossilized imprints of dinosaur skin and other features 2. extremely rare because these soft tissues usually decay
9
2. Trace Fossils a. Trackways (sets of footprints) - usually made in mud or fine sand sites
10
Fossil footprints have yielded information about:
* Speed and length of stride * two or four legs * stalking behavior * existence of dinosaur herds and stampedes * how the tail is carried
11
b. Toothmarks=generally appear on
bones c. Gizzard Rocks = Gastroliths - swallowed stones to help grind their food - Coprolite = fossilized feces * up to 40 cm (16 inches) in diameter
12
d. Burrows and Nests - considered trace fossils of the animal that laid them
Similar presentations
© 2025 SlidePlayer.com Inc.
All rights reserved.