Time Scale
What is the name of the chart scientists use to show Earth's history from oldest to newest, including major chunks of time like eras and periods?
Geologic time scale
What is the name for the preserved remains or traces of living things from the past?
Fossils
What name do scientists give to the supercontinent that included most of Earth's land about 250 million years ago? What does it mean?
Pangaea = all lands
Which type of fossils is not an actual part of an organism, but evidence it existed, like footprints, nests, or eggs?
trace fossils
Name one major era in the geologic time scale (for example, an era that occurred before humans).
Paleozoic, Mesozoic, Cenozoic
Which type of dating tells us the order in which rocks and events happened, but not how many years ago they happened?
Relative dating
What kind of fossil is made when an organism's hard parts are replaced by minerals, leaving a rock copy?
Petrified fossil (permineralization)
Name one of the mountain ranges that were connected during Pangaea?
Appalachian Mountains, Greenland Mountains, Caledonian Mountains, Atlas Mountains
What major event ended the Mesozoic Era and caused many species, including most dinosaurs, to disappear?
large asteroid impact, lower climate temperatures, large volcanic activity
Which era is often called the "Age of Dinosaurs"?
Mesozoic
Which type of dating gives a numerical age for a rock or fossil (for example, 65 million years)?
Absolute (radiometric) dating
How can finding the same fossil species in rock layers on different continents help scientists? (One-sentence answer)
It suggests those places were once connected or had similar environments; helps correlate rock layers across continents.
What is the name of the "C" shaped sea between Laurasia and Gondwana?
Tethys Sea
Using the Geologic Time Scale in your notes (or homework assignment) put the following time periods in order oldest to youngest.
Jurassic, Permian, Cretaceous, Triassic, Cambrian
Cambrian, Permian, Triassic, Jurassic, Cretaceous
Which era do we live in now? (Name the era)
Cenozoic
What is the principal called that states in an undisturbed sequence of sedimentary rock, the oldest layers are on the bottom and the youngest are on top?
Law of superposition
What is an index fossil and why is it useful for telling the relative age of rock layers?
An index fossil is from a species that lived for a short time but was widespread; it helps identify and match rock layers of the same relative age.
What were the landmasses that were originally part of Gondwana?
South America, Africa, India, Australia, Antarctica
What major event ended the Mesozoic Era and caused many species, including most dinosaurs, to disappear?
The asteroid impact at the end of the Cretaceous (K–Pg) plus associated volcanic activity and climate change
Give one key life or Earth-surface change that happened during the Paleozoic Era.
Paleozoic saw the rise of many marine animals, the first land plants and animals, and the formation of large coal beds.
Explain briefly how scientists combine relative dating from rock layers with absolute dating to build the geologic time scale. (Short answer; 1–2 sentences)
Scientists use relative dating (like superposition and fossils) to order events and use absolute dating (radiometric ages) to assign numbers of years; combining both places events on the geologic time scale
Scientists find a sequence of fossils in rock layers that shows simple marine organisms in lower layers and more complex land plants in higher layers. What does this pattern tell us about life through time? (Short explanation)
It indicates life started in the oceans and became more complex and later moved onto land; shows evolution over time and environmental change.
What are the 4 pieces of evidence for Pangaea?
fit of continents, fossil evidence, geologic evidence, and paleoclimate (glacier deposits in warm areas)
A scientist finds two rock layers with different fossils. The bottom layer has ammonites, and the top layer has trilobites. What can you conclude about when each fossil organism lived? What law states this?
Ammonites are older than trilobites. The Law of Superposition
What is the Cenozoic era known for?
Age of mammals and development of modern ecosystems.