Middle & Late Cambrian Flashcards
When did the Middle and Late Cambrian occur?
509-485 million years ago
What are some Middle Cambrian fauna?
What group do they belong to?
How are they preserved?
Belong to the BURGESS SHALE FAUNA
Anomalocaris, Opabina, and Hallucigenia
Most are SOFT-BODIED animals that have been fossilized through carbonization
Where can the BURGESS SHALE FAUNA be located? Where did they live?
British Columbia Canada
LIVED ALONG THE WESTERN EDGE OF NORTH AMERICA CONTINENT
How was the BURGESS SHALE FAUNA preserved?
These creatures were buried quickly beneath SUBMARINE LANDSLIDES
Since they lived at the base of a steep reef escarpment that shed material on top of them
DIDN’T HAVE TIME FOR THEIR SOFT TISSUES TO ROT AWAY
Where can this steep reef escarpment be seen? (Place)
Can be clearly seen in the cliffs of YOHO NATIONAL PARK, BRITISH COLUMBIA, CANADA
What is a Pikaia? What is so special about them? What group was it a member of?
NOTABLE BURGESS SHALE MEMBER
Considered to be the earliest chordate based upon its notochord (backbone)
What is a notable thing about the Burgess Shale fauna that modern-day fauna does not have?
Have body plans and features that DO NOT exist in animals today
What is a body plan? What order of species are they?
SET OF MORPHOLOGICAL FEATURES COMMON TO MANY MEMBERS OF A PHYLUM OF ANIMALS
What did early animals show during the Cambrian explosion? What happened to them?
Early animals show the BROADEST RANGE of body plans and forms in ALL of Earth’s history
Many of these early experiments (body plans) went extinct
What is this evolutionary behavior that Cambrian animals showed?
This evolutionary behavior (of having a broad range of body plans) is called EARLY EXPERIMENTATION, LATER STANDARDIZATION
Takes time for animals to refine their bodies
What are the different continents during the time of the Paleozoic before Pangea?
LAURENTIA: North America-Greenland (moves freely until Pangea)
BALTICA: NW Europe (another isolated landmass that moves freely, will interact with Laurentia soon enough
SIBERIA: Russia (third isolated landmass that moves freely, will remain independent for quite a while)
GONDWANALAND: Supercontinent
What is Gondwanaland and what does it comprise itself of?
SUPERCONTINENT
Antarctica, South America, Africa, Australia, and India
WILL STAY INTACT THROUGH THE FORMATION OF PANGEA
Where are the old landmasses from the Paleozoic aka Laurentia, Baltica, Siberia, and Gondwana located today?
When did the Earth’s sea level rise during the Paleozoic? Why? (Early Paleozoic)
Sea levels began to rise at the START of the Cambrian
Began to rise as the ice melted from SNOWBALL EARTH
What happened to Laurentia when the sea level rose?
Much of Laurentia was submerged throughout the Cambrian
What is WALTHER’S LAW?
Environments that occur next to each other will stack atop each other as sedimentary rock layers
A deep ocean can not just go to a swash zone, needs transitioning layers of sediment
What does the rise and fall of sea levels do to the surrounding environment?
The rise and fall of sea level moves the beach and all associated environments
What is the term for sea level RISING? How does this occur? What would the trend of sediment be?
TRANSGRESSION
Occur when deep ocean environments stack ATOP coastal environments
RISE IN SEA LEVEL OVER TIME
SANDSTONE —> MUDSTONE —> CHALK
Shallow—————————————->Deep
What is the term for sea level FALLING? How does this occur?
REGRESSION
Occur when coastal environments stack atop deep ocean environments
Where in the Grand Canyon records evidence that sea level rose? (Rocks)
TAPEATS SANDSTONE, BRIGHT ANGEL SHALE, and MUAV LIMESTONE record TRANSGRESSION
Sandstone —> mudstone —> limestone
