Clues about Evolution - Fossils

1. Define the 5 types of fossilsO Mineralized Fossils – minerals can replace

wood or bone to create a piece of petrified wood or mineralized bone fossil.

O Imprint Fossil – a leaf, feather, bone or entire body of an organism can leave an imprint on sediment that will harden into a rock.

O Frozen Fossil – the remains of organisms can be trapped in ice that remains frozen for 1000’s of years

O Cast Fossil – minerals can fill in the hollows of animal tracks or other parts of an organism to create a cast.

O Amber Fossil – when the sticky resin of certain cone-bearing plants hardens over time, amber forms. It can contain the remains of organism.

2. What is a fossil?

OThe remains, an imprint, or a trace of a prehistoric organism.

3. What type of rock will you find most fossils located in? What are 3 examples of this type of rock?OSedimentary

OLimestoneOSandstoneOShale

What type of sedimentary rock will you find the most

fossils?

OLimestone

What does the fossil record give us?

OInformation about organisms that lived in the past.

What are the two basic methods of determining a

fossil’s age?

ORelative DatingORadiometric Dating

Explain relative dating.

OUses the ages of the layers of sedimentary rocks

OEx – a fossil found between 30,000 year old and 50,000 year old rocks make a fossil to be between 30,000-50,000 years old.

Explain radiometric dating.

O Uses radioactive elements (gives off radiation)

O The amount of radioactive element compared to the amount of nonradioactive element in the rock that the fossil is found in will tell how old the fossil is.

Where will you find younger layers of rocks?

OCloser to the top of the ground

Where will you find older layers of rocks?

OFarther underground

Does relative dating produce an approximate or estimate age of the

fossil?

OEstimate

Which method is more accurate – relative dating or radiometric

dating?

ORadiometric Dating

Why are there gaps in the fossil record?

OMost organisms do not become fossils.

What provides indirect evidence that evolution has

occurred?

OFossils

What is embryology?

OThe study of embryos and their development. O look on page. 167

OFish/Chicken/Rabbit embryos

Explain what homologous structures are? Give 4

examples.

OStructures made up of the same kind of bones.

OHomologous – body parts that are similar in origin and structureOPorpoise flipperOFrog forelimbOHuman armOBat wing

What are vestigial structures?

OStructures that don’t seem to have a function.OEx: snakes no longer have

back legs, but have a pelvic bone

How does DNA help with the theory of evolution?

ODNA can be compared from living organisms to identify similarities among species.

OAncient DNA shows evidence of how species evolved from their extinct ancestors.

ODetermine how closely related organisms are.O Dogs and Bears