1. EUKARYOTIC EVOLUTION AND DIVERSITY

2. ENDOSYMBIOSIS A theory to explain the origin of eukaryotic organisms - Eukaryotic cells represent the merger of two or more simpler cells (possibly prokaryotic ones) - One cell (host) engulfs a different cell (endosymbiont) and the engulfed cell survives and becomes part of the engulfing cell

3. ENDOSYMBIOSIS

4. Eukaryotic organelles originated from ancestors of free-living prokaryotes ** Evidence for endosymbiosis found in the mitochondrion and chloroplast

5. CHLOROPLASTS AND MITOCHONDRIA Chloroplasts were once free-living prokaryotes later engulfed by other larger cells This arrangement benefited the host by making it more energy efficient - Converting solar energy into sugar - Extracting energy stored in sugar so cell can do work

6. CHLOROPLASTS AND MITOCHONDRIA Evidence: - Membranes of chloroplasts and mitochondria are similar to prokaryotes - Ribosomes are similar to prokaryotic ribosomes - Reproduce by binary fission - Contain a circular chromosome with gene sequences matching prokaryotes

7. CHLOROPLASTS AND MITOCHONDRIA

9. MULTICELLULARITY Cells in prokaryotic aggregations carry out the same function, without specialization - A colony, not one individual First multicellular organisms existed 1.2 to 1.5 billion years ago, half as long as unicellular organisms - Created from colonies of dividing individual cells where some specialized and increased in specialization

10. MULTICELLULARITY

11. LIFE CYCLES AND REPRODUCTION PROKARYOTES: asexual reproduction UNICELLULAR EUKARYOTES: asexual reproduction, complex asexual reproduction, sexual reproduction

12. LIFE CYLES AND REPRODUCTION HUMAN REPRODUCTION - Two individuals make haploid gametes (eggs and sperm) - Gametes fuse to form a diploid zygote - Zygote undergoes mutiple cellular divisions

13. LIFE CYCLES AND REPRODUCTION