Act. 91: Fossilized Footprints Challenge How can fossil footprints be used to study the behavior of animals that were alive millions of years ago? Key Vocabulary: Hypothesis Inference Observation

Key Vocabulary Hypothesis – an educated guess about a solution to a problem that can be tested Observation – An objective description of one or more pieces of evidence Inference – A conclusion drawn from observed evidence.

Activity 91: Fossilized Footprints Image from: http://www.newark.osu.edu/facultystaff/personal/jstjohn/Documents/Cool-fossils/Trace-fossils.htm These dinosaur tracks were found in a geologic formation known as Dakota Sandstone. Scientists have concluded that these tracks are from the Lower Cretaceous Period (circa 145-66 million years ago). They were found on the eastern side of Dinosaur Ridge in Colorado.

Dinosaur Ridge, Colorado

A Quick Review… What is a fossil? What can fossils tell us about past life? What can they NOT tell us? Why is studying fossils important?

What is the difference between an inference and an observation? Observation: an objective description of one or more pieces of evidence Inference: a conclusion drawn from observed evidence Write this Down!!

What's a Hypothesis? A Hypothesis is an educated guess about something. To be scientific is needs to be testable.

Doing the Activity… Let’s Read the Introduction on Page 12. Glue in SS 91.1 “Footprint Analysis” Follow the Procedure on pages 13- 14 for Part A Answer Analysis #1-2 in your notebooks with your groups. Continue following the procedure for Part B. Answer the questions in complete Sentences in your notebooks.

Fossil Footprint Card 1

Fossil Footprint Card 2 Observations: Inferences:

Fossil Footprint Card 3

Analysis Question 1 Your hypothesis should have changed as new evidence was introduced. It is important to keep observations and inferences as separate as possible because inferences can restrict how open one’s mind is to both the possible implications of new evidence and the need to re-interpret old evidence

Analysis Question 2- Page F-15

Part B 10a) The increased depth of the larger footprints in Card 3 provides evidence that the weight of the larger animal may have increased. This supports the hypothesis that the larger animal picked up a baby, carried off the smaller animal, or ate a carcass

10b) It remains unclear whether it was carrying an infant or a dead prey animal, either in its mouth or in its stomach.

11a) Table 2 suggests that the larger animal did not become substantially heavier, although the slight increase in depth of the footprints may indicate the residue of a meal. This would support the hypothesis that the larger animal ate part of the smaller animal.

11b) It cannot be interred whether the larger animal attacked and killed the smaller animal or came upon the smaller animal after it had died. Also, it is possible that the larger animal carried off the smaller one or ate all of it. The weight of the smaller animal might been so much less than that of the larger one that the added weight made little difference in track depth.

11c) Increased footprint depth between cards 1 and 2 may indicate that the animals were striking the ground more powerfully as they struggled. However, even the drastic increase in depth of the larger footprints in card 3 of Table 1 may have occurred simply because the soil was softer in that area.