Introduction: One of the most difficult things for the human brain to comprehend is the depth of geologic time because it is challenging to visualize the magnitude of numbers like a million or billion. This lab explores concepts in relative dating, absolute age dating, and fossil succession to explore how geologists structure Earth’s vast history.
PART 1: Understanding Geologic Time:
Use the https://ucmp.berkeley.edu/education/explorations/tours/geotime/gtpage1.html webpage to answer the following questions:
⦁ How many pages would be in the “A History of the Earth” book if each page represented 10,000 years of Earth history?
⦁ For the events listed below, fill in how many years ago the event happened, and what page it would be on in the “A History of the Earth” book.
Event Years ago Page # in book
Formation of the Earth and Moon
Earliest life appears
Early land plants
Largest mass extinction
Dinosaur extinction
Early hominid “Lucy”
⦁ What is the difference between relative date and absolute date? (Use the U.S. history timeline you create to help answer this question.)
⦁ What is the Law of Superposition (what does it tell us)?
⦁ Fill in the following information for the fossils shown in step 7 of the activity.
Fossil Fact about the organism Date the fossil:
Trilobite
First appeared:
Brachiopods
Height of diversity:
Eurypterids
Went extinct:
Ammonites
Went extinct:
⦁ Which of the fossils is the earliest (oldest)?
⦁ What is radiometric dating, and what does it tell us?
⦁ Based on the data from the radiometric dating of the volcanic ash layers, what is the age range for the layer of rock the ammonite fossils are found in?
⦁ The geologic time scales starts with the formation of the Earth. When did the Earth form?
⦁ Fill in the following information for the eons and eras in the geologic time scale.
Time Period Fact Millions of years ago
Eons Phanerozoic
Proterozoic
Archean
Pre-archean
Eras Cenozoic
Mesozoic
Paleozoic
⦁ Use the information from the geologic timeline to identify what period each of the following events occurred in.
⦁ Animals first appear in the fossil record: _____________________________________
⦁ Evidence of life on land: ____________________________________
⦁ First trees and forests appear: ________________________________
⦁ Pangaea forms: _______________________________________
⦁ Largest mass extinction occurs: _____________________________
⦁ Dinosaurs roam the earth:__________________________________
⦁ Dinosaurs go extinct:_______________________________________
⦁ Mammoths, saber-toothed cats, giant sloths, humans, and ice ages
(aka, when the movie “Ice Age” takes place): ___________________________
PART 2: Life Has A History
The point of this exercise is to introduce you to life history and to gain an understanding of how long life has been on the planet. You will also see how life has evolved through time and how we can determine the relationship of one species to another or the relationships between groups of species at higher taxonomic levels.
For this portion of the exercise you will be using the following website:
https://ucmp.berkeley.edu/education/explorations/tours/intro/Intro5to12/tour1nav.php
Read the instructions and work your way through the module. You will need to click on the answers and get them correct before advancing. For some portions you must simply click on a word or two. Please read through the questions first then work through the module.
On the second page of the module you will find a link to “definitions to scientific terms”, click on this link and using the definitions as a guide, put the following definitions in your own words so that you understand what they mean (DO NOT CUT AND PASTE):
Geologic time:
Fossils:
Natural selection:
Biodiversity:
Cladogram:
Evolution:
Speciation:
Evolutionary relationships:
Paleontologist:
Taxon:
Working through the module, answer the following questions:
1. Of the 30 million species of living things estimated to exist today, how many of them are not animals?
2. Find the timeline. How many millions of years did dinosaurs exist on Earth before they became
extinct? (this is the length of time from when they first appear until their extinction)
3. Name at least five things other than bones that can be preserved as fossils.
4. Explain what divergence is.
5. What types of evidence are used to determine evolutionary relationships?
6. In your own words, explain how Geospiza Fortis is a good example of natural selection.
7. Describe two other mechanisms for evolution in addition to natural selection.
8. Give an example of an animal that has gone extinct because of human influence and explain what happened.
PART 3: What did T.Rex taste like?
In this exercise you will learn how we use evidence from both the modern and fossil record to determine the relationships between organisms both past and present. We can also make some inferences about some characteristics we don’t have direct evidence for. As with part 2, please read the questions then work your way through the module to answer the questions. Although there is an additional assignment at the end of the module, we are not doing that one and you are done with the module when you have the answer to the questions.
Go to this website to begin:
https://ucmp.berkeley.edu/education/explorations/tours/Trex/navigation.html
Questions:
1. Who did Max inherit dimples from?
2. What is a “common ancestor”?
3. In the quiz, which is the best definition for lineage? Circle one: A B C
4. Which feature do humans, hares, caimans, and parrots share that the other three lineages did not inherit?
5. When did the skull opening in front of the eye develop? Before the human/hare or between human/hare and the caiman/parrot?
6. What did Dinosaurs likely taste like?
PART 4: Welcome to the geologic time scale.
In this portion of the exercise you will become even more familiar with the current geologic time scale by filling in a table and dates in millions of years before present. Go to this website to view the time scale. If you like you can download and/or print it for your reference: https://www.geosociety.org/GSA/Education_Careers/Geologic_Time_Scale/GSA/timescale/home.aspx?hkey=8668fe3f-c0a8-4dd8-aaca-13603b24c9e0
Geologic Time Scale
Place the age range of each time unit next to it using the Geologic Time Scale. Use the “Body Ages (Ma)” and “Picks (Ma)” ages. Ma = mega annum = millions of years before present. No dates are to be placed where it says “None”. Some dates are filled in for you in order to help keep you on track. Please be sure to read the tiny print at the bottom of the GSA time scale, it has information helpful to filling in portions of the table in this exercise.
Eons Eras Periods
Hadean – 4600 – 4000 None None
————————————————————————————————————————————————————————————-
Archean – 4000 – 2500 Eoarchean – 4000 – 3600 None
Paleoarchean – None
Mesoarchean – None
Neoarchean – None
————————————————————————————————————————————————————————————-
Proterozoic – Paleoproterozoic – Siderian – 2500 – 2300
Rhyacian –
Orosirian
Statherian –
Mesoproterozoic – Calymimian –
Ectasian –
Stenian –
Neoproterozoic – 1000 – 541 Tonian –
Cryogenian –
Ediacaran –
————————————————————————————————————————————————————————————-
Phanerozoic – Paleozoic – Cambrian – 541.0 – 485.4
Ordovician –
Silurian –
Devonian –
Mississippian –
Pennsylvanian –
Permian –
Mesozoic – Triassic –
Jurassic –
Cretaceous –
Cenozoic – Tertiary – Paleogene –
Neogene –
Quaternary – 2.58 – today
