1. Eukaryotic Evolution
XYU

2. 2.3 - Eukaryotic Evolution
Initially, there were only prokaryotes on Earth
Eukaryotic evolution can be explained by a theory called endosymbiosis
ENDOSYMBIOSIS: a symbiotic relationship between two or more prokaryotic cells
1) one cell engulfs (host cell) a different type
2) engulfed cell (endosymbioont) survives and becomes an integral part of the engulfing cell

3. Possible “engulfed” components
1) Chloroplast
2) Mitochondrion
They have remained because they are both essential

4. Mitochondrion Most likely was an aerobic bacterium
It was engulfed by a prokaryote
It did not get destroyed
Provided a means to extract energy from sugar

5. Chloroplast Most likely was a cyanobacterium
It was engulfed by a prokaryote
It did not get destroyed
Provided a means to convert solar energy into sugar

6. Evidence to support this theory
Mitochondria and Chloroplastas have the following in common with prokaryotes:
1) it has its own circular DNA!
–Chloroplasts have very similar genes to cyanobacteria
2) it has a membrane similar to the structure of prokaryotes, since the membrane remained after the prokaryotic cell engulfed it.
3) undergoes binary fission to replicate organelles

8. ENDOSYMBIOSIS

9. HWK
Pg. 71 # 4, 8,11,