Precambrian (End of the Proterozoic) Flashcards
What happens after the Snowball Earth?
Diverse multicellular life emerges almost immediately following the end of snowball earth
New exotic forms of life
What are the most earliest evidence for multicellular life? When?
Belongs to a group called the Ediacaran organisms
Appeared near the end of the Proterozoic
What are Ediacaran organisms?
Were soft-bodied, had no mouths, and lived a stationary lifestyle
THEIR RELATION TO PLANTS AND ANIMALS REMAIN UNCLEAR
How did Ediacaran organisms live? How did they eat?
Must have regulated their cells through a process of diffusion
Diffusion evens out inequalities of concentration
How did Ediacaran organisms eat?
Used diffusion to suck in food (higher concentration outside the cell) and pulled out waste (waste is higher in the cell)
How did Ediacaran organisms get preserved?
Their preservation is exceptional since soft tissue decays rapidly
EVEN SO, THE PRESENCE OF MICROBIAL MATS AIDED PRESERVATION
How did microbial mats form fossils?
Microbes within the mat bind sediment together, transforming the seafloor into something moldable
A body pressed into the mat leaves a mold like memory foam
What is the process of making a mold from a microbial mat?
When sand buries a creature, their impression is molded into the microbial mat
After decay, sand fills the mold to form a CAST
What is the significance of the preservation of Ediacaran life?
All Ediacaran life is preserved as sandstone casts formed within the microbial mat enhanced molds
Without these mats, we’d have nothing
What coincides with the rise of Ediacaran organisms?
Coincides with the rise in ATMOSPHERIC OXYGEN
What is NECCESARY for multicellular life?
OXYGEN O2
What are sponges?
Simple cells held together by a common animal protein called COLLAGEN
What is needed to form collagen?
Collagen needs atmospheric O2
Collagen can not form without atmospheric O2
