The Solid Earth - Chapter 9: Life of the Geologic Past Flashcards
When did life evolve?
During the Precambrian
Why was the life evolved during the Precambrian not recorded in fossils?
Simple and soft bodied
Although fossils from that time are rare, well preserved remains of minute organisms such as bacteria and blue green algae called _____ have been discovered that extend the record of life back nearly 3.5 billion years
cyanobacteria
The fossil record of animals dates from the late Precambrian and includes distinctive ________ believed to have been created by elongate wormlike animals
trails and burrows
True or false: the fossil record demonstrates the existence of a diverse group of multi-celled organisms as the Precambrian ended
True
The Paleozoic era (the longest - encompasses 325 million years) is marked by the appearance of life forms that possessed ____
hard parts
Life in early Paleozoic time was restricted to the ___
seas
Life in early Paleozoic time consisted of ____ groups
invertebrate
Give 5 examples of Paleozoic invertebrate groups
Trilobites Graptolites Brachiopods Bryozoans Mollusks
What period is the golden age of trilobites?
Cambrian
What was introduced by Ordovician times?
Small marine invertebrates called brachiopods started to outnumber the trilobites. The adults were attached to the floor, but the larvae were SWIMMING which meant they were more well spread. This time also marked the appearance of cephalopods
What are cephalopods?
Highly developed mollusks that were mobile and became the major predators of the Ordovician… their descendants include octopus, squid. These could reach nearly 30 feet.
As the Silurian gave way to the Devonian, some 400 million years ago, plants that had adapted to survival at the water’s edge began to ____
move inland
By the end of the Devonian, the fossil record indicates the existence of forests with trees _____ high
tens of meters
Ordovician fishes with armor plates evolved during the ____ to include primitive sharks and bony fishes
Devonian
Age of the fishes
Devonian
Two groups of bony fishes in late Devonian time
lungfish
lobe-finned fish
By late Devonian time, what started to invade the land?
Air breathing amphibians with fishlike heads and tails
The conditions during the remainder of the Paleozoic were ideal for ______ to the land
amphibians
What was abundant for amphibians to snack on?
Plants and insects
True or false: the amphibians wildly diversified during the Paleozoic
False
Where did the coal deposits associated with the industrial revolution originate?
Vast swamps that extended across North America, Europe, and Siberia in the Pennsylvanian period
The Paleozoic ended with the ___ period
Permian
Describe the Permian period (big ol’ event)
A time when the earth’s major landmasses joined to form the supercontinent Pangaea
By the close of the Permian, ____ percent of the amphibian families had disappeared and plants declined both in number and variety
75
Why did animals like trilobites go extinct?
Because they could not adapt to the circumstances of the Permian (like the climate change associated with Pangea and the mass extinction)
What is the nickname for Mesozoic era?
Age of dinosaurs
What separates the Paleozoic and Mesozoic?
A profound difference in the fossils in Permian strata and those in younger Triassic rocks
The life forms at the dawn of the Mesozoic era were those that had ____
survived the great Permian extinctions
Conditions in the Mesozoic favored those groups able to adapt to ____
drier climates
What was a member of the plant kingdom that survived the Permian extinction?
gymnosperms
Dinosaurs became dominant and remained unchallenged for ________ years
100 million
Why were gymnosperms important evolutionarily?
They were seed spreading and didn’t need water to bound them
Name three examples of gymnosperms
cycads
conifers
ginkfoes
What were the largest plants in the Mesozoic forests?
Conifers
What are modern descendants of conifers?
Pines
Firs
Junipers
The reptiles are the first true ____ life forms
Terrestrial
How do reptiles reproduce?
Shell covered eggs that can be laid on land
Some dinosaurs were carnivorous. What is the obvious example?
Tyrannosaurus
Brontosaurus is (herbivorous/carnivorous)
herbivorous
True or false: some dinosaurs were warm blooded
True
Which group of dinosaurs took to the air and are called “dragons of the sky”?
Pterosaurs
Of the large number of Mesozoic reptiles, only a few survived to recent times. Name four of these.
Turtles
Snakes
Crocodiles
Lizards
The demise of the great reptiles is attributed generally to ____
their inability to this group to adapt to some radical change in environmental conditions
What is a nickname for Cenozoic era?
Era of recent life
What time span does the Cenozoic envelop?
66 million years
What type of plants came from the Cenozoic era?
Angiosperms (flowering plants with covered seeds)
What is another term for gastropod
snail
What are the fossils that are one of the most studied because they help correlate Tertiary sediments?
foraminifers
The strata of foraminifers are valuable because …
They yield more oil than rocks of other ages
What is another animal centric nickname for the Cenozoic
age of mammals
When did primitive mammals evolve?
late Triasssic
What are some distinct qualities of mammals?
Born live
Maintain body temperature (warm blooded)
Body hair
Efficient heart and lungs
What two groups of mammals evolved and expanded to dominate the Cenozoic?
marsupials
placentals
