Chapter 14 TEST Flashcards
True or False
Earth is thought to have formed about 4.6 billion years ago
True
True or False
The conditions on primitive earth were very suitable for life
False
True or False
Geological events on Earth set up conditions that would play a major role in the evolution of life on earth
True
True or False
By the end of the mesozoic, the continents took on their modern shape
True
True or False
The first organisms appeared on land between 3.9 to 3.4 billion years ago
True
Trace fossil
A foot print, trail or burrow, providing evidence of animal activity
Amber-Preserved
A fossil embedded in tree sap, valuable because the organism is preserved intact
Petrified Fossil
An exact stone copy of an original organism, the hard parts of which have been penetrated and replaced by minerals
Fossil
Any evidence of an organism that lived long ago
Imprint
The fossil of a thin object (leaf of feather) that falls into sediments and leaves an outline when the sediments harden
Mold
The empty space left in rock, showing the exact shape of the organisms that were buried and decayed there
Cast
An object formed when a mold is filled by minerals from the surrounding rock
Explain how relative dating works
Scientists look at rock layers and come to a realization that the bottom layers are older and the top layers are younger
What is the limitation of relative dating
You cannot determine the actual age in years
What dating technique is often used by paleontologists to determine the specific age of a fossil
Radiometric dating
How do scientist use radiometric dating to determine the ages of rocks or fossils
Scientists compare the amount of radioactive isotopes and the new isotope it decayed into
Whe did the first stromatolite occur
Pre-Cambrian
When did primates evolve and diversify
Cenozoic era
What era is divided into the Triassic, Jurassic, and Cretaceous periods
Mesozoic era
What era saw an explosion of life (invertebrates and the plant phyla)
Paleozoic
What era did mammals appear in
Mesozoic
What era did flowering plants occur
Mesozoic
What era did amphibians and reptiles appear in
Paleozoic
Early scientists believed that life arose from____ through a process called_____
Non living Matter; Spontaneous eneration
For how long did animals like pterosaurs, mosasaurs and other dinosaurs dominate the planet?
1 hundred million years
What are scientist trying to figure out?
Why they (pterosaurs, mosasaurs and other dinosaurs) disappeared
What were the tiny shelled sea creatures called in the limestone layers
Forams
What mysterious find did Cr. Alvarez notice in the rock layers
Forams suddenly disappeared
What was the gray band called that separated the two layers
The K-T boundary
What is the correct order of eras
(Pre-Cambrian) Paleozoic, Mesozoic, Cenozoic
What two periods does the K-T boundary separate?
Mesozoic, Cretaceous
Was there a GRADUAL change in forams as the rock layers approached the K-T boundary
NO
What was a difference in the forams above the boundary and below it
size
What rare element is found on earth that is found in meteorites
Iridium
How much more of Iridium was there, compared to the surrounding rock?
30%
If a supernova was the cause of the element being found on earth there would there have also been another isotope present. What was it an was it found
Plutonium-244, no
What was Louis Alvarez’s hypothesis about an asteroid strike
It would be found all over the earth
How many nukes would an asteroid strike be equivalent to
100 million nukes
What important biological process would have stopped because of the debris in the atmosphere
Photosynthesis
True or false
The asteroid impact hypothesis was immediately accepted by the scientific community
False
Without finding a crater, scientists had to rely on other evidence to support the asteroid impact hypothesis. What were some of those pieces of evidence
Glass beads “Spherules” found in the K-T layer and shocked quarts
What could displace various types of rock from the ocean onto land
Tsunamis from asteroid impact
Where was the crater eventually found
Yucatan Peninsula, Gulf of Mexico
Which would have the fossils of dinosaurs, the layers above or below the K-T boundary in the Hells Creek formation of Montana, North Dakota, and South Dakota
Below
What was the fate of dinosaurs within 1000km of the impact site
Broiled alive
If they were further away there demise was probably linked to…….
Sulphurous gas poisonings
After the impact how many of all plant species died
60%
What plant was the first to replace flowering plants on barren landscapes
Ferns
What animals seemed to survive the post impact world
Small, burrowing animals
