Evo Bio Test 1: Diversification of plants and animals

% marine species fossilized

2-4% (marine most likely to fossilize)

Phyla

monophyletic biological groups that share distinct body plans

First Multicellular Animals

Neoproterozoic

Earliest Large Organisms

Ediacara Forms found in Ediacaran period

Lack shells or hard parts

Appearance of Shells

early Cambrian

big for fossil record

Cambrian Explosion

when all major body plans originate

organisms were swept up in a cloud of suspended mud and buried, sediment is low in oxygen → everyone got preserved

Porifera

sponges with differentiated cells but no organs

Lobopodia

Soft-bodied aquatic worm-like fossils

Nematodes

Round worms or eel worms

Arthropods

insects 80% of

Brachiopods

Have hard shells

Generally lophophore bearing

Annelids

trochophore larvae

Segmented worms

Molluscs

trochophore larvae

Major clades are cephalopods and gastropods

End-Permian extinction

60 % of families and 90% of organisms died out

Climate change was the main culprit

biggest

• Driven by volcanic activity and possibly meteor activity.

End Cretaceous (K-T) extinction

60-70% of species went extinct

most recent

meteor

modern extinction cause

changes in land and sea use