Daily Warm-Up Exercises Day 36 On your 4.5-meter geological timeline, about where would trilobites first appear? (You may use your books and notes to answer this.) Trilobites appeared toward the beginning of the Cambrian period, which was at the start of the Paleozoic era. They would be near the heavy line between the Paleozoic era and Precambrian time, on the today side of the line. Use the 45-meter class timeline and one of the 4.5-meter timelines to show students when trilobites first appeared. Daily Warm-Up Exercises Daily Warm-Up Exercises 1

Relative Scale and Magnification Exercise 7.1 Exercise 7.1 Image comprehension focus: Relative Scale and magnification Goal: Practice determining the scale of images using scale legends Module Images: Resources book p. 41 (modified), transparency #33 (p. 319)/Lab notebook p.51, and p. 85 Type of Activity: Student Activity: Objective: This activity should be done prior to the fossil index activity in Part 1, section 5. The purpose of this activity is to provide an opportunity for students to use what they have learned so far about issues of scale to analyze images used in this investigation. Activity one procedure: Students will use what they have learned so far about issues of scale to analyze and critique two images in this investigation. >>>next slide<<<

CaSE Book Student Resources Book, page 51 Procedure: Show the students the modified image from p. 41 (this slide), and have them find the corresponding image in their book. Ask them to use what they know about scale legends (the markers that indicate the magnification used in the image) to determine which is wider at its widest point, the Composita trilobata or the Ovatia (Linoproductus). Guide the students in a discussion in which they should explain the logic behind their answer and how they approached the problem. [The Composita trilobata is larger. Even though the Ovatia is larger as drawn, it is at a higher level of magnification as indicated by the fact that a smaller distance (.5 cm vs. 1 cm) is represented on the scale legend. In the case of the Ovatia, the scale indicating 0.5 cm is 1 cm long. The Ovatia is approximately 3.5 cm wide so if each 1 cm represents 0.5 cm, it is actually approximately 1.75 cm wide (3.5 * 0.5). In the case of the Composita trilobata, the scale indicating 1 cm is approximately 1 cm long. The Composita trilobata is approximately 2.5 cm wide so if each 1 cm represents 1 cm, it is approximately 2.5 cm wide (2.5 *1).] Note the potential problem using different scale markers in adjacent pictures creates since in this case the visual gives the wrong idea of the relative size of the two. >>>next slide<<<

CaSE Book Student Resource Book, pp. 52-53 and Lab Notebook, p. 51 Procedure: Show this slide containing images from Resources, p. 85 and Lab Notebook, p. 51. This upper chart is part of the reading (step #12) so you can introduce it as such: “We are going to further investigate the importance of scale by looking at an image from your reading.” Explain that this image illustrates when various species of animals and plants appeared, and note that there is a problem with the image. If one wasn’t careful appearance of the image could lead to a wrong assumption about the length of time certain species have existed on the Earth. Ask the students to use the information about the length of various periods from the lower chart (which they have seen in Investigation 6) to identify the problem with the image on p. 85. [The problem is that the periods are shown as if they were the same size when in reality they are not (e.g., the quaternary period is 1.6 million years while the tertiary period is over 65 million years)] Both of these visuals are misleading since they represent very different amounts of time with similar visual units (e.g., the actual difference in time of existence between animals with shells and birds is much greater than appears to be indicated in the image). Conclude the activity reinforcing the idea that one needs to be careful not to make assumptions based on how an image appears. >>>end of exercise<<<

Identify Index Fossils (Part 1, steps 2-9) Investigation 7 Fossils and Time

Fossils Fossils are the remains or traces of organisms that have been preserved in Earth's crust. They provide geologists with important evidence about prehistoric environments. Some fossils also provide evidence of the age of rock layers. These fossils are called index fossils. Daily Warm-Up Exercises 6

Index Fossils Not all fossils are Index Fossils. Index fossils are fossils of organisms that lived for only a short time, but in many places around the world. Which would be a better index fossil: a fern that lived for 300 million years or a trilobite that lived in many areas for a few million years? The trilobite, because it lived for a short time over much of the Earth. Daily Warm-Up Exercises 7

Index Fossil Key Daily Warm-Up Exercises 8

Index Fossil Key The Index Fossil Key shows the period in which the organism lived and whether it lived early, middle, or late in the period. Early means toward the beginning of the period. Late means toward the end. For example, early Permian rocks are older than late Permian rocks. Daily Warm-Up Exercises 9

Index Fossil Identification Write the name of the Index fossil Write the age of the Index fossil Remember: Not all fossils are index fossils Daily Warm-Up Exercises 10

Bryce & Zion Canyon Fossils Identify the index fossils and their ages. Daily Warm-Up Exercises 11