1. Development of multicellularity

2. Advantages of size Being big prevents others from eating you
Being big allows you to eat others
Change in ratio of surface area to volume as size increases.
Metabolic rate is somewhat size dependent

3. Disadvantages of size
Total energy requirements go up with increasing size
In air and water, big causes more rapid sinking if not compensated for extensions of body or changes in specific gravity
Diffusion becomes a problem

4. There must be an overall advantage
Life as it evolved has become bigger (in bigger packages)
Proximate and ultimate causes/effects

5. How does it happen Divisions Multinucleation
Nuclear divisions--mitosis
Cytoplasmic divisions--cytokinesis
Multinucleation
Syncitial--multinucleate, but no cell membranes. (fungi--saphrophytic/zoic
Multicellularity--multiple mitoses and cytokineses

6. Cellular adhesion
Glue--cell cement
Physical structures

7. Advantages of multicellularity
Increase size
Division of labor
Specialized cells

8. Disadvantages of multicellularity
Total volume of food goes up
Diffusion distances increase making the physical process of diffusion less functional

9. Volvocine method Volvox is a colonial algae Not much division of labor
Hollow sphere with cells in outside layer
colony

10. Protosponge approach
Collar cells