Fossils and fossilization by Muhammad Sohail Riaz Hashmi
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This document discusses fossils and the fossilization process. It begins by defining fossils as the remains or traces of ancient plants and animals preserved in rock. There are different types of fossils including body fossils, trace fossils, imprints, and chemofossils. The document then explains how fossils are formed through burial and replacement of organic materials with minerals over millions of years. Finally, it describes the key steps in fossilization including decay, transport, burial, and alteration of remains, which is dependent on environmental factors.
Fossils and fossilization by Muhammad Sohail Riaz Hashmi
- 2. Presented by: Muhammad Sohail Riaz Presented to: Miss Roha Ramash
- 3. Table of Contents Fossils Fossils What are the fossil types? What Things Become Fossils? How are Fossils Made? What are the modes of fossil preservation for body fossils? Turning to Stone When Did They Live? Fossilization Fossilization Taphonomy What are some factors that can affect fossilization How fossilization dependent upon the environment
- 4. Fossils The term “fossil” is used for any trace of past life Fossils are the remains of plants and animals that lived a very long time ago They are usually found in rock and stone Fossils are important because they tell us a story about things that lived on the earth before us
- 5. What are the fossil types?
- 6. Body fossils: Actual parts of an organism, unaltered or altered bones, shells, leaf imprints Body fossils of plants and animals almost always consist only of the skeletonized or toughened parts because soft tissues are destroyed by decay or by scavengers Many species of plant and animal fossils are known only from their fragments
- 8. Trace fossils: Also called ichno fossils Evidence of life that is not a body fossil tracks, burrows, casts OR fossil which consist of the marks left behind by the organism while it was alive They are very important because they represent both the anatomy of the maker in some way as well as its behavior
- 9. Cont…… The majority of these trace fossils were made by infaunal (living in sediment) animals, especially deposit feeders like worms Bird tracks at some locations in the Green River Shales of Wyoming and Utah are also common
- 11. Imprints Imprints are simply the external molds of very thin organisms, such as leaves and trilobites They are often found in rocks such as sandstone and volcanic ash Trilobites of the Marjum Formation in Utah are often found as impressions
- 13. Chemo fossils Chemo fossils or biomarkers Past life leaves some markers that cannot be seen but can be detected in the form of biochemical signals These are known as chemo fossils or biomarkers
- 15. Altered Permineralization Pores in tissue are filled by minerals Replacement Replacement of tissue with minerals Altered Carbonization Tissue material is decomposed or reduced to a film of carbon
- 17. What Things Become Fossils? Animals and plants become fossils So do nests, eggs, footprints and even animal droppings
- 18. How are Fossils Made? Fossils are made from the hard parts of plants and animals, such as: - Bark Seed cases Bones Teeth These parts do not easily rot away after plants and animals die Fossils take millions of years to form
- 21. What are the modes of fossil preservation for body fossils?
- 22. Unaltered Original Material: Original, unaltered material from the living organism unaltered bone or shell Encrustations or entombments: Material is trapped inside coating such as amber
- 23. Amber Amber is a natural tree resin That had hardened through various chemical changes Sometimes this sap surrounds an insect, preserve it with perfect details & look like stone Amber may trap foreign objects, which are called inclusions
- 25. Freezing Freezing is a type of preservation in which an animal falls into a crevasse or pit and remains frozen Such ideal remains are rare and almost always never very old Animals have been restricted to ice age rhinoceros and hairy mammoth These remains have preserved bone, skin, muscle, hair and even internal organs
- 27. Drying or Dessication Remains of animals that have been found thoroughly dried include camel, ground sloth and even marsupial wolf These remains were found in caves in arid and semi-arid areas of the Southwestern United States, South America, New Zealand and Australia The dried dung of cave dwelling giant ground sloths have also been found in caves
- 29. Turning to Stone For example: - A starfish dies The soft parts of its body rot away quickly The harder parts slowly get covered by mud After millions of years, the starfish is deep in the ground
- 30. Cont…. The mud around it is crushed by the land on top and turned to stone So are the remains of the starfish Millions of years later, the stone gets worn away and the fossil can be seen
- 32. From the Sea The first creatures on the earth lived in the sea Some sea creatures made good fossils because they had hard shells and hard bones
- 34. Plants At first, there were only living things in the sea Slowly, over millions of years, plants began to grow on the land Some of these plants have left fossils in the rock
- 35. Green river
- 36. Animals Animal fossils are often bones that have been turned to rock Sometimes part of the flesh is preserved, but most of the time only skeletons remain Because of this, it is more difficult to find fossils of invertebrates. (Invertebrates are animals that don’t have bones.)
- 37. Cont…. We have discovered several types of animal fossils: bones, skin, teeth, claws, eggs, nests, muscles, and organs We have also found lots of fossils of footprints, which tell us how much animals and dinosaurs weighed and how they might have walked
- 39. When Did They Live? First Fish: 570 million years ago First plants on land: 440 million years ago First insects and amphibians: 400 million years ago First reptiles: 360 million years ago First dinosaurs: 245 million years ago First birds: 210 million years ago
- 40. Fossilization Fossilization is the process by which a plant & animals becomes a fossil This process is extremely rare & only a small fraction of the plants & animals that have lived in the past 600 million years are preserved as fossils Those plants & animals that do become fossils generally undergo, with some exceptions, serial key steps First, the soft tissue that exists during life decays leaving behind only the "Hard parts" (bone, shell, teeth)
- 41. Cont….. Second, hard parts may be transported & broken This causes the fossilized remains to be incomplete representation of the living animal It is much more common to find a fragment of shell or bone then it is to find a complete skeleton Third & most important, hard tissues become buried & altered
- 42. Cont…. In most cases this involves destroying the original material from which the hard parts were made as minerals are slowly dissolved & replaced by new ones often times a hard part is dissolved without being replaced by new material , leaving behind only an impression or mold of the original animal If this mold is filled with sediment that is later cemented into rock it will make a cast of the original animal
- 43. Taphonomy The process of fossilization is called taphonomy First, there is the death of the organism There are certain processes that can happen to the organism before it is buried Processes can include body decay
- 44. What are some factors that can affect fossilization Body construction Environment Predators
- 45. How fossilization dependent upon the environment The environment plays a crucial role The best scenario Area with high rate of sediment deposition The environment can also affect where the fossil is found Drier environments, lead to erosion