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
