Cell
Multi-cellular
- First cell to evolve was prokaryote (3.5 billion years ago)
- Prokaryotes started to evolve when the number of prokaryotes
increased to the point there was limited resources (food).
- Prokaryotes evolved into eukaryotes – How?
Current theory is called the Symbiotic (Big Gulp) Theory.
1) Prokaryote (A) can’t make food but is large
2) Prokaryote (B) can make food but is small and can’t protect
itself
3) Prokaryote (B) starts to live inside of (A)
4) Prokaryote (A) protects (B) and (B) makes food for (A)
5) Prokaryotes (A & B) now can survive better then other cells
6) Over time (millions of years) prokaryote (B) becomes a
permanent part of prokaryote (A).
7) Over time – prokaryote (B) will not need certain structures due
to prokaryote (A) will do the functions for prokaryote (B).
Ex: structures for moving, processing, etc.
8) Prokaryote (A) now has a membrane-bound organelle and now
becomes a eukaryote
- Eukaryotes evolved into colonial organisms (genetically identical
cells living together in group).
- Colonial organisms evolved into multi-cellular organisms when the
cells in the colonial organisms started to differentiate.
Ex: The outer cells would do only movement with cilia and the
cells inside would lose their cilia and produce more energy for
themselves and the outer cells.