2.1 identify the major stages in the evolution of living things, including the formation of:
- organic molecules
- membranes
- prokaryotic heterotrophic cells
- prokaryotic autotrophic cells
- eukaryotic cells
- colonial organisms
- multicellular organisms
2.5 process and analyse information to construct a timeline of the main events that occurred during the evolution of life on earth
Identify: recognise and name construct: put together
The Formation of organic molecules: Complex organic molecules formed in water on Early Earth. The first of these were probably amino acids, nucleotides and simple carbohydrates.
The formation of Membranes: Thought to be the precursor of cells. May have formed when hydrophobic regions of molecules clustered together to form a boundary around them.
The formation of heterotrophic prokaryotic cells: May have been the first cells on earth. No membrane-bound organelles or nuclei, and they rely on organic molecules as an energy source.
The formation of autotrophic prokaryotic cells: The ozone layer began to form and due to this cells may have developed the pathway to make their own food (photosynthesis). There is evidence of cyanobacteria in stromalites. No membrane-bound nucleus or organelles.
Eukaryotic Cells: DNA of these cells are organised into chromosomes within a membrane-bound nucleus, and they posses membrane-bound organelles such as mitochondria and chloroplasts.
Colonial Cells: Composed of groups of similar cells clustered together, which may include bacteria, algae and slime moulds.
Multicellular organisms: These organisms represent the most advanced of life forms; where cells in the body show differentiation to carry out specific functions as a coordinated unit, for examples humans. Evolved around 750 million years ago.
Timeline of Events: 3.8 billion years ago | Organic molecules | 3.5 billion years ago |