Earth’s Biological History – Flashcards
Unlock all answers in this set
Unlock answersquestion
The ______ parts of organisms are most likely to become fossils.
answer
Hard
question
Preserved animal tracks are called ______ fossils.
answer
Trace
question
A ______ may tell a geologist when, where, and how an organism lived.
answer
Fossil
question
A ______ is the cavity left behind in the rock after an organism's hard part has dissolved.
answer
Mold
question
Fossils are the ______, imprints, or traces of once-living organisms preserved in rock.
answer
remains
question
fossil formed when an outline of the original organism is formed from left-over carbon
answer
carbonaceous film
question
made when sediments fill in a cavity made when an object decayed and the sediments harden into rock
answer
cast
question
the order of events and the relative age of rocks is determined by examining the position of rocks in a
sequence using this method
answer
relative dating
question
fossils of species that lived on Earth for short periods of time and were abundant and were widespread
geographically
answer
index fossils
question
states that for undisturbed rocks, the oldest rocks are on the bottom and the rocks become younger and
younger toward the top
answer
principle of superposition
question
hollow place in rock made when an organism dies and is buried and holes in the rock let air or water reach it
and dissolve the organism.
answer
mold
question
List the types of catastrophic events have contributed to extinctions.
answer
Impacts from asteroids or comets
Climatic changes
Volcanic/seismic activity
question
Geologic time is divided into units based upon types of
answer
organisms
question
A limestone bed containing fossils that are 550 million years old is ______ than a bed of sandstone containing
fossils that are 400 million years old.
answer
older
question
If a species can evolve or _______to a changing environment, its descendants will survive.
answer
change
question
Life-forms that existed during the Paleozoic Era included
answer
Fish, early reptiles, trilobites
question
Humans first appeared during the _________ Era.
answer
Cenozoic
question
The Appalachian Mountains formed during the __________ era.
answer
Paleozoic
question
List the life-forms of the Cenozoic Era.
answer
Humans, flowering plants, insects, reptiles, marine mammals
question
Why do we know so little about the Precambrian Era?
answer
Precambrian rocks and fossils have been deeply buried,
and most of the rocks have been changed by the heat and pressure deep within the earth. Also, since
most of the life forms were 'soft' organisms without hard parts, few fossils were formed.
question
What natural factors which can cause extinctions?
answer
Climate changes, volcanoes, global warming, natural
extinctions, changes in oxygen levels in the sea, massive impacts from comets and asteroids
question
A life-form that evolved during the _________ Era was the dinosaur.
answer
Mesozoic
question
Sponges and jellyfish arose near the end of the ___________ era.
answer
Precambrian
question
Why are trilobites such good index fossils?
answer
existed for a relatively short
time
• lived over large areas of the
world
• exhibit specific characteristics
(physical traits)
question
The Rocky Mountains formed during the ________ era.
answer
Mesozoic
question
The division of Earth's history into smaller units is called the_________________________.
answer
Geologic Time Scale
question
In a series of undisturbed rock layers where shale lies between sandstone below and limestone above, what is the
order of the rock layers from oldest to youngest?
answer
Sandstone (one on the bottom is oldest), Shale,
Limestone
question
Man-made factors that have caused extinctions include what activities?
answer
Rainforest clearing, over-harvesting,
pollution, habitat destruction
question
Pangaea formed during the ___________ era.
answer
Paleozoic
question
What were the life forms of the Precambrian era?
answer
Early sea life, sponges, jellyfish, algae, fungi, cells
question
What is relative dating? What is relative age?
answer
Relative Age is the age of something in comparison to the ages of
other things. The use of relative ages to date other rock layers or fossils is called Relative Dating.
question
What were the life forms of the Paleozoic Era?
answer
Reptiles, flowering plants, fish. Remember this was the Age of
Fish!
question
What are the conditions that MUST be met for fossil formation to occur?
answer
The organism must be buried quickly,
preserved from decomposers and scavengers, and must contain hard parts which can be more easily
preserved.
question
The ______________ states that each rock layer is older than the one above it.
answer
law of superposition
question
Which life forms existed during the Mesozoic Era?
answer
Reptiles, dinosaurs, snakes, amphibians
question
What event signaled the end of the Paleozoic Era?
answer
Mass extinctions of invertebrates
question
How are the time periods determined on the Geologic Time Scale?
answer
Based on the organisms/life forms present and
extinctions
question
If a layer of sandstone lies on top of a layer of limestone in which a 300-million-year-old fossil is found, and there are
no unconformities, the layer of sandstone must be _____________.
answer
younger
question
When did Pangaea break apart?
answer
Mesozoic Era
question
Both the hard and soft parts of organisms are encased in amber, ice, or tar to form __________ fossils
answer
preserved
question
Trilobites existed during which era?
answer
paleozoic
question
If the same types of fossils are found in two separate rock layers, what does this tell us about the age of the rocks and
when they formed?
answer
Formed at the same time = same age
question
When did the Himalayas form?
answer
Cenozoic
question
What is Natural Selection?
answer
Natural Selection is the process that explains how species can change over time, as
traits that increase chances of survival and reproductive success persist and are passed down, while
those that aren't go away (because the organisms don't survive to pass the traits on...)
question
How do each of the following types of fossils form: Trace, permineralized, cast, preserved?
answer
Trace fossils are the footprints, trails or burrows of organisms.
• A mold fossil is the cavity left behind in the rock after an organism's hard parts have dissolved.
• A cast fossil forms when a mold of an organism fills with sediment and is compacted into a rock that
holds the shape of the original organism.
• Permineralized or petrified fossils form when an organism's remains are exposed to mineral-rich water,
and mineral replacement occurs, turning the remains to rock.
question
Changes among species of similar species which do not aid in survival are called ________.
answer
variations
question
What life forms persist in the Cenozoic Era?
answer
Humans, plants, insects, reptiles, marine mammals
question
What event(s) led to the extinction of Dinosaurs? How?
answer
BIG COMET or ASTEROID... flames and smoke
caused destruction and climatic changes...
