Bell work Pick a science word and write the definition. Chapter 7 or the glossary

Title of Notes: Fossils Pgs. 18, 19 & 20 RS Goal for the lesson: I can describe a fossil.

I’ll know I’ve got it when… Learning target I can describe a fossil. Today I am… learning about fossils and the geological time scale. So that I’ll be able to… Explain what characterizes a fossil and understand how they are dated. I’ll know I’ve got it when… I can describe what fossils are.

Preserved remains of any living thing. Fossils Preserved remains of any living thing.

Requirements of a fossil…. For remains to be considered fossils, scientists have decided they have to be over 10,000 years old.

Carbon-14 has an approximate half life of 5,700 years. Radiocarbon dating A chemical analysis used to determine the age of organic materials based on their content of the carbon-14. Carbon-14 has an approximate half life of 5,700 years. All organic material has decaying Carbon-14 in it. However, plants and animals that are still alive constantly replace the supply of carbon in their systems and so the amount of Carbon-14 in the system stays almost constant. Once a plant or animal dies the Carbon is no longer being regenerated and so the Carbon-14 starts to decay. In this way, by measuring the amount of Carbon-14 in the body of a prehistoric animal or plant, a scientist can deduce when the plant or animal died.

Death Left: A fish during its life. Right: The fish dies and shortly after sinks to the seafloor.

Decay and burial Left: After several weeks the soft body tissues have mostly decayed. Right: Tectonic activity causes nearby sediment to bury the fish.

Sediment accumulation and permineralization Left: Several months pass and all that remains of the buried fish is its skeleton. Right: As times passes more sediment accumulates above the fish and the skeleton is gradually compressed and permineralized.

Uplift and exposure Left: Over time the rock is distorted and uplifted by geological forces associated with continental movement, raising it above sea level. Right: The uplifted rock is exposed to weathering and gradually erodes away, eventually exposing the tip of the fish's skull at the surface.

Discovery and extraction Left: A paleontologist recognizes the fish by the small area of skull exposed and begins to carefully extract the specimen. Right: A Pomognathus fish from the Houghton Quarry - the skull is clearly visible, and what parts of the skeleton remain are buried.

Geological Time Scale The first geologic time scale was proposed in 1913 by the British geologist Arthur Holmes (1890 - 1965). This was soon after the discovery of radioactivity. Holmes estimated that the Earth was about 4 billion years old.

Period Tens of millions of years. Geological Time Scale Era Two or more geological periods comprise an era (Hundreds of millions of years in duration.) Period Tens of millions of years. Epoch The smallest division of geologic time, lasting several million years. Age An age is a unit of geological time which is distinguished by some feature (like an Ice Age).

Eon Era Period Millions of years ago (MYA) Phanerozoic Cenozoic Quaternary 1.8   Tertiary 65 Mesozoic Cretaceous 144 Jurassic 206 Triassic 248 Paleozoic Permian 290 Pennsylvanian 323 Mississippian 354 Devonian 417 Silurian 443 Ordovician 490 Cambrian 540 Proterozoic 2500 Archean 3800 Hadean 4600

Biggest fossil This gigantic plant-muncher (named after Argentina, where its remains were found) measured about 120 feet from head to tail and may have weighed over 100 tons (200,000 lbs). Just one vertebra of Argentinosaurus is over four feet thick! Set of bones that extend from the spinal column. 2,000 lbs = 1 ton

Tertiary Cretaceous Jurassic Triassic Permian Carboniferous Devonian Quaternary Tertiary Cretaceous Jurassic Triassic Permian Carboniferous Devonian Silurian Ordovician Cambrian Precambrian

Emily Baldry with the toy shovel she was using when she found her fossil.  When the fossil was first dug up, it looked like a large clump of hard mud.  A fossil expert removed the hardened mud to reveal the fossil pictured above.

Cast fossil These are formed with a mold is filled in Types of fossils Mold fossil When an animal or plant dies, it may fall into mud or soft sand and make an impression or mark in the dirt. The body is then covered by another layer of mud or sand Cast fossil These are formed with a mold is filled in Compression fossil Plants/animals become trapped between layers of sediment and get smashed flat. Trace Fossils The remains of tracks, burrows, eggs, nests, and fossil coprolites (poop).

Resin fossil Plants, mostly trees, secrete sticky stuff called resin. Sometimes insects, other small animals, or bits of plants get stuck in the sticky resin. The resin hardens overtime and is preserved in rock making a fossil.

Notebook activity pg. 18 LS Create a geological time scale. Draw a picture to represent each Era. Pg. 152 - 155