Fossils! Key Point #1: Fossils are the remains or imprints of an organism that lived long ago. Preserved tissue, shell or skeleton turned into stone, imprints left in the Earth.

Rock Layers The further you dig, the further back in time you are traveling.

Out loud questions Surface of the earth 1. Which species is oldest? Species A Species B and A Species B Species C 2. Which species is youngest?

A little bit harder 1. Sedimentary Rocks stack on top of each other horizontally. They form over MILLIONS of years

A little bit harder Intrusion layer: Rocks that were liquid (maybe magma from a volcano) and cut across stacked rocks. INTRUSION LAYERS ARE ALWAYS YOUNGER THAN THE STACKED ROCKS!!!

KEY POINT #2 There are two ways to find out how old a fossil is Radioactive dating Relative dating

1. Radioactive Dating Uses the breakdown of radioactive elements (remember you learned what an element was in physical science!) to date fossils. Gives an actual age in years for a fossil!

How you might be tested on this If there is 1200 lbs of Stronitium left, how old is the sample fossil you are examining?

2. Relative dating Shows whether a fossil is older or younger than other fossils by comparing the same fossils found in different locations

The most important tool for relative dating is INDEX FOSSILS Index fossil: a fossil is used to find the age of a group of rocks. An index fossil must have these four characteristics: Must be easy to identify Must be very common Must have lived for a short period of time Must have existed all across the world

If index fossils are found in one group of rocks, then the rocks with these same fossils must be the same age EVEN IF THEY ARE FOUND REALLY FAR APART FROM EACH OTHER Index fossils Index fossils

If index fossils are found in one group of rocks, then the rocks with these same fossils must be the same age EVEN IF THEY ARE FOUND REALLY FAR APART FROM EACH OTHER

Out loud: What is older, 4 or 5? Why?

Key Point #3 Fossils provide evidence for evolution in two ways: General trends Transitional forms

1. General Trends Fossils show that life on earth has changed dramatically over time! Important: The further you dig, the more simple the creatures are.

2. Transitional Forms Transitional form: an organism that has traits somewhere in between its ancient ancestors and organisms that came after it.

Famous fossil record Transitional forms have some characteristics of the old, some of the new. They show change over time!

DNA The more DNA 2 organisms share the more closely related they are.

DNA Human: ATTACTGAC Chimp: ATTACTGAG Deer: AAAACTGCG Chimps and humans are more closely related than humans and deer

DNA DNA provides proof of evolution by showing that organisms that are more closely related have MORE DNA in common.

Which one is the cow? cat cow horse human

Embryology Embryos are eukaryotic organisms in their earliest stages of development.

Embryology

Embryology All embryos look almost identical in the early stages of development—that’s not a coincidence! The similarities in this stage represents a common ancestor that all the organisms evolved from.

The fact that all animal embryos are so similar shows that ALL animals evolved from the SAME common ancestor

Embryology Embryos will be most similar in early stages/different in latest stages.

BINGO!!!!! Fill in your board and let’s play  Best guided practice EVER!

Rules You need bingo in any direction to win We are going over EVERY OTHER problem Do not say the answer to the one we are not going over in class If you do, you cant win!

What is older, fossil 1 or fossil 8?

What is older, A or B? B A

Organism B is known as a ______________________ CAN BITE BUT HAS NO TEETH CAN BITE, CHEWS PREY WITH TEETH B CAN BITE, HAS TEETH BUT SWALLOWS PREY WHOLE Organism B is known as a ______________________

An imprint of an organism

A type of rock that is formed as horizontal layers over millions of years

What is YOUNGER, 3 or 6?

What is older, 1 or 6?

What is older, M or F? F M

This fossil is found in two areas thousands of miles away from each other, it helps scientists date the two sets of rocks. It is called a _______ fossil F M

Which layer is the oldest? Fossil #1 Fossil #2 Fossil #3 ROCK LAYER A ROCK LAYER B ROCK LAYER C

Which fossil is the youngest? ROCK LAYER A ROCK LAYER B ROCK LAYER C

Which fossil is least complex? ROCK LAYER A ROCK LAYER B ROCK LAYER C

Where would you look for a transitional form between Fossil #2 and Fossil #3 in the picture below? ROCK LAYER A ROCK LAYER B ROCK LAYER C

What is older, C or D?

Which is older, D or E?

Which rock layer is the youngest?

The technique where scientists use elements present in rocks to find out how old they are

Which is older, K or F? J F K G

Intrusion rocks are always _________ than the sedimentary rocks they cut through

Work on the worksheet!

In your folder Grade sheet Exit Slip Daily Quiz Independent Practice Homework: Worksheet