Multicellular life Flashcards
Significance of 02 levels
low levels cells would not be possible as the cells would asphyxiate
High levels of O2
led to evolution of giant insects that lacked a circulatory system
Who are our close relatives
Choanoflagellates
What are choanoflagellates
unicellular eukaryotes that form colonies during part of their life cycle
What are the simplest animals
Sponges
What supports the evolutionary link between choanoflagellates and animals
the close resemblance of choanocytes in sponges with choanoflagellates
What supports the evolutionary link between choanoflagellates and animals
the close resemblance of choanocytes in sponges with choanoflagellates
Colony formation
cells able to stick together
True multicellular organism
- selective cell adhesion
- cells have different properties; division of labour
- composed of genetically identical cells
Driving force for colony formation
Alga chlorella vulgaris
it develops into stable colonies within less than 100 generations in the presence ochromonas vallescia
downside to colony life
genetic conflict
what is genetic conflict in colonies
not all cells are genetically identical in colonies
this allows cheater cells to exploit the altruism to others
what is volvocaceae
resemble the unicellular eukaryote chlamydomonas
simple species of volvocacae
e.g gonium
each cell can divide to produce a new organism
volvox
species of volvocacae
they become differentiated into cell types
