Lecture 20 - Cambrian

Cambrian Explosion

Rapid diversification of life around 541 million years ago.

Precambrian Time

Era from 4,500 to 543 million years ago.

Phanerozoic Eon

Current eon, spanning from 543 million years ago to present.

Hadean

Earliest geological eon, 4,500 to 4,000 million years ago.

Archean

Eon from 4,000 to 2,500 million years ago.

Proterozoic Era

Era from 2,500 to 543 million years ago.

Paleozoic Era

Era from 543 to 248 million years ago.

Mesozoic Era

Era from 248 to 65 million years ago.

Cenozoic Era

Current era, from 65 million years ago to present.

Small Shelly Fauna

Early Cambrian fossils with hard shells, indicating preservation.

Cloudina

Enigmatic organism showing signs of predation in fossils.

Archaeocyatha

Ancient cup-like organisms, early reef builders, extinct quickly.

Lingula anatina

Modern inarticulate brachiopod, similar to Cambrian fossils.

Trilobites

Extinct arthropods, significant in Cambrian fossil record.

Burgess Shale

Fossil site preserving soft-bodied organisms from 505 million years ago.

Charles Walcott

Paleontologist who discovered the Burgess Shale in 1909.

Soft Tissue Preservation

Burgess Shale's unique ability to preserve delicate structures.

Ediacaran

Period preceding the Cambrian, known for soft-bodied organisms.

Helcionellid Mollusks

Small shelly fossils, part of Cambrian fauna.

Inarticulate Brachiopods

Group of brachiopods still existing today, dating back to Cambrian.

Mud Slides

Rapid burial process that preserved soft tissues in fossils.

Fine Grained Sediments

Sediments that enhance preservation of delicate fossil structures.

Mobile Predators

Organisms indicated by boring marks in fossils.

Cambrian Fossils

Fossils from the Cambrian period, showcasing early life forms.

Small Shelly Fossils

Fossils that represent early hard-shelled organisms.

Tomopteris sp.

Modern polychaete worm representative from the Cambrian.

Canadia spinosa

Polychaete worm fossil from the Burgess Shale.

Ottoia tricuspida

Fossil priapulid worm from the Burgess Shale.

Priapulus caudatus

Modern priapulid worm related to ancient fossils.

Oryctocephalus bugessensis

Trilobite fossil from the Burgess Shale.

Olenoides serratus

Burgess Shale trilobite used for dating formations.

Marrella splendens

Most common Burgess Shale fossil, ~15,000 specimens.

Hallucigenia

An enigmatic Cambrian organism, morphology debated.

Anomalocaris

Large Cambrian predator with uncertain classification.

Chengjiang Locality

Fossil site in China, 525 to 510 million years ago.

Naraoia spinosa

Arthropod fossil found in the Burgess Shale.

Microdictyon sinicum

Cambrian fossil from Chengjiang, China.

Haikouella

Early chordate fossil from the Lower Cambrian.

Phylum Onychophora

Group including modern velvet worms.

Lobopodia

Group of soft-bodied organisms with uncertain segmentation.

Soft-body preservation

Fossilization method preserving delicate structures.

Specimen volume

Over 50,000 specimens from Walcott Quarry.