Life and Death

Naturally preserved remains/traces of animals/plants Is actually quite rare but reasonable ampunt has been preserved

Low energy environments eg deep ocean, lake eg not mountain stream Sedimentary rocks

• Burial soon after death • Environmental conditions with little exposure to O2, light and minimal bacterial decay • Organism made of geoliogicall stable materilas Sub 0 temps and low O2 also sometimes allow fossilization of soft bodied animals

Trace fossils are the REMAINS OF ACTIVITY, so anything made/produces by the animal: burrow, footprints, poop… Body fossils are fossilized PARTS OF THE ORGANISM: teeth, leaves, bark, bone…

Mold: An imprint has been made into the sediment/rock and this imprint has been preserved Cast: Stencil/mould has been filled up so the shape of the original organism is recreated and has been preserved

Rocks containing both soft and hard bodied animals

Organism squashed by layers of sediment/rock so after its decay, all thats left is a thin layer of carbon imprints because the rest of the organis materila has decayed,

Mostly simple organisms, disc shaped, but since they didnt have shells, preservation potential small

Animals with shells

Evolution of reptiles/ complex forms of life

Mammals

Composed of water, carbon dioxide, carbon monoxide, methane, nitrogen and sulphur Building blocks of life

Earliest fossils (though a bit controversial) Stromatolites are rocks with a very fine layering of carbonate made by cyanobacteria (excreted O2) trapping and binding sediment particles.

Presence of light isotope of carbon in minerals in rocks dated from 3500 million years ago C12 is preferred by living organisms (>C13, C14) eg during photosynthesis, so presence of C12 is evdience for bacterila photosynthesis

1) Oxygen produced by cyanobacteria reacts with dissolved iron in water to produce iron oxide –> banded iron formations 2) around 2400 million years ago, tipping point is reached where oxygen is no longer just reacting with iron to produce iron oxide in oceans, it is gathering in the atmosphere–> concentrations remained low until about 580 million years ago, allowign complex life to develop

-Disc shaped organisms with radial ridges -Preserved as impressions (no shells, because no such thing as predators yet) -Produce cholesterol so animal rather than plant

-replace ediacran fauna –> much more diverse -complex body parts (eyes, brain, shell, skeleton…)

Rocks that contain fossils of plants and animals that are rarely preserved, usually because they are soft bodied

is a fossil-bearing deposit exposed in the Canadian Rockies of British Columbia, Canada. It is famous for the exceptional preservation of the soft parts of its fossils. At 508 million years old, it is one of the earliest fossil beds containing soft-part imprints.

-Oxygen poor sea floor preventing bacterial decay and scavenging -flattened and preserved as thin films of carbon

Some animals were predators (as can be seen in fossil remains in which gut and last meal have been preserved), so animals needed to evolve strategies to avoid being eaten

Some animals in the burgess shale are unlike any others in the paleozoic era and even the modern day. Burgess shale almost like an evolutionary experiment–> animals experimenting with the types of forms they can take on and only the best adapted niches continued to develop

-Micro fossil -Eel like predator

-particularly abundant prior to Permian/Great Dying) -Mode of life: filter feeding–> water comes in, goes through LOPHOPHORE (feeding FILTER) where nutrients are absorbed and rest is shot out of organism. PEDICLE (stalk like structure) allows brachiopod to attach itself to rocks, corals and seafloor Plane of symmetry: cuts through two shells rather than between shells -