Bellwork: Copy the bolded words and your answer choice

• The concept of gene flow is demonstrated when a cow is driven off from its herd, joins another herd, and reproduces. When the cow contributes to the gene pool of the new herd, which of these most likely increases?

A. Natural selection B. Genetic variation

C. Environmental fitnessD. Reproductive mutations

Science Fact of the Day:The Giant Kelp algae (Macrocystis pyrifera) is the

fastest growing organism on earth and can grow at a rate of 70cm (two feet) a day.

Science Fact of the Day:Rafflesia Arnoldii is the largest flower in world,

and can grow as big as an umbrella.

Evidence of Evolution

Fossil Record

EmbryonicMolecularAnatomical

Homologies Biogeography

Fossil Record

Fossil: The evidence in rock of the presence of a plant or an animal from an earlier geological period

*further down = older (usually)*carbon dating can help determine age*transitional fossils can show evolutionary changes*incomplete

Types of Fossils

How Fossils form

The picture to the right shows a series of major Biological Events that have taken place over the last 488 Million Years!

Biologists were able to piece these events together based on evidence collected from fossils.

Take notice of the extinctions. What happened immediately after each one?

Carbon Dating is a method widely used to date fossils to find out where they lie on the evolutionary timeline.

Take a look at the graph. It shows how the percent of carbon-14 remaining in a sample indicates the age of the sample.

What would the age of a bone be if it contained only 10% of Carbon-14?

What percent of Carbon-14 would you expect to find in a sample that is 7580 years old?

• According to the table, if ¼ of the original radioactive carbon is present in a fossil, what is the fossil’s age?

• Which Isotope would be best for measuring the age of a rock layer estimated to be about one million years old?

Homework tonight: Cladograms by Bozeman Science

Cornell Notes plus you MUST draw the cladogram

Cladograms = diagrams that we use to show phylogenies

A phylogeny = evolutionary history*show relationships

*use evidences of evolution*can be changed with new data

How do you build a cladogram?

Step 1: Create a table listing all the characteristics of the organisms

Hair Bipedal Tail Foot flexibility

Written Language

Human

Ape

Mouse

Monkey

Step 2: put an X in the boxes that have the trait (for each organism)

Hair Bipedal Tail Foot Flexibility

Written Language

Human X X X

Ape X X X

Mouse X X

Monkey X X X X

Step 3: count up the Xs. The more Xs the older the trait.

Hair Bipedal Tail Foot Flexibility

Written Language

Human X X X

Ape X X X

Mouse X X

Monkey X X X X

Total 4 3 2 2 1

Step 4: Draw a diagonal line to represent time. Each point will represent a common

ancestor. Each branch is a new species. Traits are written on the main line.

hair

Mouse

Step 5: Continue until the cladogram is complete

hair

Mouse

bipedal

Monkey

Tail

Ape

Written language

Human

You try…

Characteristic Sponge Jellyfish Flatworm Earthworm

Cells with flagella X X X X

Body Symmetry X X X

Bilateral Symmetry X X

Segmented body X