BIOL108 Lecture Notes - Lecture 20: Hermaphrodite, Microvillus, Cambrian Explosion

• School: University of Alberta
• Department: Biology (Biological Sciences)
• Course: BIOL108
• Professor: Lien Luong

Document Summary

Biol 108 - lecture #20 - animalia pt. Common ancestor of animals: resembled choanaflagellates: sister taxa to animals. Cell morphology was very similar to sponges (porifera) Make up the inside of the organism. Evolution of multicellularity: the hypothesis was that a ball shaped of choanoflagellates may have evolved into a simple animal with ecto and endodermal layers. Multicellularity evolved many times - in fungi, independently in plants, etc. What may have happened was that the choanaflagellates started to stick together - If they were genetically compatible with each other, they stayed together. Looking at the development of organisms (how they develop their body) gives you insight about their evolutionary history. If aggregations of cells are able to cooperate (grow as a colony) and thus survive better and produce more of their own kind, they have higher. Meant that all evolutionary pathways described could be possible: selective advantages. Could avoid being eaten by other larger organisms.