The Cambrian Explosion Flashcards
when was the Cambrian Period
the cambrian explosion was approximately 485- 540 mya
what is the most common type of fossil
Sedimentary Fossils
what are the types of eyes?
pit eyes, lensed, eye and the compound eye
how does fossilisation occur
fossilisation will only happen if the organism is quickly removed from any oxygen, as this would allow micro-organisms to decompose it
what are the functions of the lens?
to focus light on the retina
what does the retina do
turns light waves into nerve impulses
what are fossils
fossils are the preserved remains of animals and plants
what are the two main types of fossils
body fossils and trace fossils
what are trace fossils
they are footprints or other imprints of organisms that have been preserved.
how are fossils formed
by perminerallisation
what is process of permineralisation
over a very long period of time particles are deposited on top of the organism and, slowly, the hard organic matter (bones, shells etc) is replaced by inorganic minerals.
how could the complex lensed eye evolve
in gradual steps from the simple ancestral eyes
