250 likes | 444 Views
Paleontology Test Review. What is a Paleontologist?. A person who studies past life (fossils). How do scientists date material older than 50,000 years? Younger than 50,000 years?. Older than 50,000 years – uranium-lead method Younger than 50,000 years – carbon-14. What are fossils?.
E N D
What is a Paleontologist? • A person who studies past life (fossils)
How do scientists date material older than 50,000 years? Younger than 50,000 years? • Older than 50,000 years – uranium-lead method • Younger than 50,000 years – carbon-14
What are fossils? • Any trace or remains of organisms that lived in the past.
What type of rock are most fossils found in? • sedimentary
Why are fossils not found in igneous rocks? • Igneous rocks are made from magma or lava. The rock would be to hot for fossils to form. They would melt in the hot rock.
What can fossils tell us about an area’s history? • What the land looked like? • What type of climate? • What type of organisms lived there?
What can scientist learn from studying fossil? • How life has changed over time • Age of rocks
What type of conditions slow down an organism’s decay? • Cold and/or dry
Are fossil records complete or incomplete? Why? • Incomplete because most organisms do not fossilize
How are fossils formed? • Organism dies • Buried fast • Mineral replaces tissues • Mineral harden and form a rock of that organism
What do fossil records tell us about organisms? • What the organism ate? • How they lived? • How organism changed over time? • That organisms have become more complex over time.
What does the fossil record tell us about climate change? • Fossils can tell us what the climate of an area might have been like in the past • Example – Fern(topical plant) found in Northern Canada might suggest that the climate of this region was much warmer and tropical than it is today.
What does the law of superposition state? • Oldest rock is below younger rock
What era are we in right now? • Cenozoic Era
What is petrifaction? • When minerals replace soft tissues of dead organisms and form a rock
How old is the Earth’s history date back to? • 4.6 Billion years old
What is the difference between and index and trace fossil? Give examples of each. • Index fossil – fossil from one geologic time period that is used to date rock • Trace fossil – fossil that shows activity of an organism. Ex: footprints, nest, trail
What is relative age and how do you find the relative age of an object? • Relative age – age compared to other objects using the Law of Superposition
What is absolute age and how do you find the absolute age of an object? • Absolute age – method of measuring the age of an event or object in years using radioactive decay • Radioactive decay • Carbon-14 – living things less than 50,000 years old • Uranium-Lead method for rocks
What is uniformitarianism? • Uniformitarianism – Principle that states geologic processes that occurred in the past occur today and happen gradually
What is original horizontality? • Original horizontality – sediments are deposited in horizontal layers
How is the geologic time scale broken down? And what does it record? • Era - Periods – Epoch (Manageable parts) • It records how life has changed overtime. • It records climate change • When major events (asteroid impacts, mass extinctions) • How old rocks are
What is a catastrophic event? Give examples. • Big event that happens fast. Examples: Earthquakes, landslides, mudslides, floods
How does most geologic change happen? • Gradually (slowly)