Fossil
records
Fossil
record is the information we get from fossils, it is arranged in chronological
order, and it helps us to study the history of life on earth.
Cambrian
explosion
It
was a period 535 million years ago and was the time when there was a rapid
increase in the diversity of multicellular life, and it was characterized by
hardened body parts that we see today such as shells or bones.
All
living things on earth originated from a single celled prokaryote that existed
around 3.8 billion years ago, this prokaryote had offspring with the ability to
photosynthesise; this oxygenated the atmosphere allowing eukaryotes to survive
which eventually led to Cambrian explosion.
Extinction is
the end of a species on a global or regional level and the most common example
of this is the extinction of dinosaurs around 65 million years ago.
Fossil is the preserved body of a dead organism and the process by which these fossils form is known as fossilisation, and the process of fossilisation occurs when the organism is not exposed to oxygen, which means it should be covered by a sediment (tiny pieces of naturally occurring solids such as earth and rock that settle at the bottom of a liquid), overtime sediment layers build upon each other in a compact way forming a sedimentary rock, and within this rock the fossilised remains can take various forms such as mould or cast fossil.