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LIFE ON EARTH FOSSILS
- MAJOR STAGES OF EVOLUTION OF LIVING THINGS
- 4 bya – Organic molecules – amino acids, proteins, carbon
compounds, etc
- 4-3.5 bya – Membranes – made of lipids and
proteins
- 3.5-2.5 bya – Procaryotic heterotrophic cells – cells without membrane-bound organelles, obtained
energy from organic molecules that existed in the primitive environment
- 2.5-2 bya – Procaryotic autotrophic cells – cells without membrane-bound organelles, obtained
energy by making their own compounds (food)
- 1.5 bya – Eucaryotic cells – These cells have membrane bound
organelles
- 1.5 bya – Colonial Organisms – Individual cells start to work together (not as 1
organism)
- 1-0.5 bya – Multicellular Organisms - Specialised cells which are dependant on each other in the
colony (as one organism)
- 1-0.5 bya – Multicellular Organisms - Specialised cells which are dependant on each other in the
colony (as one organism)
- 1.5 bya – Colonial Organisms – Individual cells start to work together (not as 1
organism)
- 1.5 bya – Eucaryotic cells – These cells have membrane bound
organelles
- 2.5-2 bya – Procaryotic autotrophic cells – cells without membrane-bound organelles, obtained
energy by making their own compounds (food)
- 3.5-2.5 bya – Procaryotic heterotrophic cells – cells without membrane-bound organelles, obtained
energy from organic molecules that existed in the primitive environment
- 4-3.5 bya – Membranes – made of lipids and
proteins
- 4 bya – Organic molecules – amino acids, proteins, carbon
compounds, etc
- EVIDENCE THAT SUGGEST WHEN LIFE BEGAN ON EARTH
- GEOLOGICAL
- Banded iron formations in rocks –rings/ layers of rusted iron Fe
(II) ions + O2 ions (from photosynthesis) Fe3O4 (sinks to sea
floor) Proves that oxygen was present in the oceans, therefore
oxygen is present at the time when the layers are red Oxygen
cant escape into the atmosphere until all the iron in the water
has been rusted and sunk to the bottom Can be found between 4
and 2 bya (mostly) Red Beds – iron rich rocks that are terrestrial
(formed on land) and generally age 2 bya (no older) They prove
that oxygen was present in the atmosphere at that time
- Banded iron formations in rocks –rings/ layers of rusted iron Fe
(II) ions + O2 ions (from photosynthesis) Fe3O4 (sinks to sea
floor) Proves that oxygen was present in the oceans, therefore
oxygen is present at the time when the layers are red Oxygen
cant escape into the atmosphere until all the iron in the water
has been rusted and sunk to the bottom Can be found between 4
and 2 bya (mostly) Red Beds – iron rich rocks that are terrestrial
(formed on land) and generally age 2 bya (no older) They prove
that oxygen was present in the atmosphere at that time
- PALEANTOLOGICAL
- Schopf claimed to find fossils dating back to
3.5 bya used 3D X rays to prove that it wasn’t just
a flaw in the rock Cyanobacteria and
heterotrophic bacteria found from at least 850
mya Stromatalites (colonial bacteria) – formed
by cyanobacteria
- Schopf claimed to find fossils dating back to
3.5 bya used 3D X rays to prove that it wasn’t just
a flaw in the rock Cyanobacteria and
heterotrophic bacteria found from at least 850
mya Stromatalites (colonial bacteria) – formed
by cyanobacteria
- GEOLOGICAL
- OXIC AND ANOXIC ATMOSPHERES
- As oxygen levels rose,
photosynthetic organisms became
more abundant, while the anaerobic
organisms were inhibited due to the
presence of oxygen.
- The formation of the ozone layer protects the Earth from UV
radiation
- The formation of the ozone layer protects the Earth from UV
radiation
- Explosion of diverse forms of plants and
animals
- The evolution of photosynthesis and
respiration
- As oxygen levels rose,
photosynthetic organisms became
more abundant, while the anaerobic
organisms were inhibited due to the
presence of oxygen.
- INVESTIGATION OF FOSSILS
- 1. Examine and classify (according to
type)
- 3. Construct a table to
summarise results
- 2. Make a labelled sketch (include size, shape and
colour information)
- 1. Examine and classify (according to
type)
- DIFFERENT TYPES OF FOSSILS
- - imprints (carbon imprints)
- - mould
- - petrified fossils (shells or
skeletons replaced by minerals)
- CAST
- - preserved remains
- - imprints (carbon imprints)
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