Station 10

Scientific Evidence of

Common Ancestry

Reporting Category 3Biological Evolution and

Classification

Essential Question – Bell Ringer

What information can be gained by examining the fossil remains of the ancestors of modern organisms?

By studying fossil remains, scientists can determine how closely related fossil organisms are to modern species. Fossil remains also give scientists insight into what environmental conditions were like where the fossil organisms lived.

Information about past life, including the structure of organisms, what they ate, what ate them, their environment, and the order in which they lived can be determined using….

A. VestigiologyB. The fossil recordC. StratologyD. Ecology

Pre-Review Question

What does this diagram represent?

Fossil Record

Pre-Review Question

Pre-Review Question• Based on DNA sequencing, which

organisms are more closely related?

A. AAC GCA TTA GCC

B. GAC GCA TTA GCA

C. AAC AAT CCA GCA

A and B

A. AAC GCA TTA GCC

B. GAC GCA TTA GCA

What type of homology does this represent?

A. MolecularB. AnatomicalC. Developmental

Why did you choose A and B as your answer to the previous question?

Pre Review Question

Because they have the fewest DNA sequence differences.

A. Molecular

Pre-Review Question

These two cladograms represent the same information.

Based on the graphic, which two organisms are most closely related?

Lab Activities

• You will now go to the lab and complete the activities for today’s topics.

Draw this chart in your journal and fill in the name of the organism and the DNA sequencing from the lab activity.

Check your work

Examine this diagram to answer the following questions in your journal.

How has the anatomy of the horse changed over time?

Skull?

Legs?

All parts of the horse’s anatomy have become larger.

The face is longer, and the cheek teeth have changed in number and size (longer and less sharp).

The lower legs and feet havechanged, and the number of toes has been reduced from four smaller toes to onelarge toe that we now call the hoof.

More Specifically The number of toes these horses have decreases in number:

•The oldest fossil has four toes; oligohippus has three; mercyhippus also has three but two are not fully formed; pliohippus has one toe but remnants of two additional ones near the knee. The modern horse, equus, has only one toe, which has evolved into a hoof while the toes have decreased in number, the skulls have increased in size.

I need to remember……..I need to remember . . .

•DNA sequences are used to determine how closely related organisms are to one another. •Examining fossil remains enables scientists to understand how modern organisms developed over time.

What do thesestructures represent?

Vestigial structuresAnalogous structuresHomologous structuresRadiant structures

Post Review Question

Post Review Question

If two different species have homologous structures, what does this tell you about their evolutionary history?

A.They share a common ancestor.

B.They do not share a common ancestor

The process by which unrelated organisms independently evolve similarities when adapting to similar environments.

A. Convergent Evolution

B. Divergent Evolution

C. Adaptive Radiation

D. Symbiosis

Post Review Question

What does the

circled structure

represent?

Vestigial structure

Analogous structure

Homologous structure

Radiant structure

Post Review Question