1. Fossils
Remains of living things that have been buried by sediment. Sediment hardens preserving shape of organism.

2. Paleontologist
A smart guy/gal who studies fossils!

3. Sedimentary rock Rock made from hardened sediment (broken pieces).
Often found near water (lakes, oceans, mud bogs…) where sediment tends to build up.
Bones, teeth, shells, seeds, stems are often left behind.

4. Types of fossils
1) Petrified – remains turned to stone by being replaced by minerals

5. Types of fossils 2) Molds and casts- Most common fossil
Mold- imprint/shape is preserved, hollow
Cast- copy of the shape of the organism

6. Types of fossils 3) Carbon film- Thin coating of carbon on a rock
Gasses escape from organism leaving carbon behind

7. Types of fossils 4) Trace fossils Evidence of activity of organism
Feces, footprint, trails
How did it live?

8. Why study fossils?
Fossils can indicate what life was like in the past…climate, geology, landforms, geography…
Fossils can tell us how organisms have changed over time (evolved)

9. Like fossils?

10. “Rocks of Ages” Relative Age vs. Absolute Age
Relative Age- “age of rock” in relation to others surrounding it
Absolute Age- # of years since the rock formed (difficult to get an EXACT date)

11. Position of rock layers
1) Law of Superposition – lower layers older than upper layers (they’ve been there longer)

12. Position of rock layers
2) Extrusion– lava hardens on surface (so newer.) AKA volcano
3) Intrusion- younger than rocks below.

13. Position of rock layers
4) Fault- younger than the rock it cuts through

14. Index fossils
Fossil that was only around for a brief time. Gives relative age of rock around it.
Ex-Trilobites

15. Geologic Time Let’s review… Absolute vs. Relative time
Methods to identify how old a rock is

16. Time is always relative…

17. Precambrian time 544 million years ago to 4.6 billion years
88% of Earth’s history
Formation of Earth, molten…then water planet…formation of primary atmosphere…

18. Eras Three major eras since Precambrian time
1- Paleozoic – (oldest) 544 million years -245 million years
2- Mesozoic 245 million years – 66.4 million years
3- Cenozoic (current) 66.4 million years- present

19. Periods Smaller units within eras Millions of years
Examples: Jurassic, Triassic, Cretaceous periods

20. How the Earth was Made Part II
On a piece of notebook paper down the following time periods.
As the video comes to each of these time periods write down 2 facts about that time period on your paper.
3.4 billion years ago (bya)
2.5 bya
1.5 bya
1.0 bya
700 million years ago (mya)
550 mya
300 mya

21. Paleozoic era 544-245 mya “Explosion of life”- Cambrian explosion
Marine life
Trilobites, Brachiopods
Jawless fish
Vertebrates (organisms with a backbone)
Plants
Insects
Amphibians- lives part of life on land, part in water
Reptiles- scaly skin and lay eggs with leathery shells

22. And then… Mass extinction 95% of life in the oceans disappeared
Fish, reptiles survived
“Permian extinction”

23. Mesozoic era Triassic, Jurassic and Cretaceous periods Conifers
Triassic, Jurassic and Cretaceous periods
Conifers
“Age of reptiles”
Mammals
Archaeopteryx “ancient winged thing”
Flowering plants
Fruits/seeds

24. And then…
Mass extinction
65 mya
Asteroid
K/T boundary

25. Cenozoic era
Mammals thrived
Grasses
Ice ages
Humans