Daily Newsletter March 29, 2012
Today's Topic: Protozoa
Suggested Reading: Introduction to Protozoology
The Kingdom Protista (Protoktista) is currently undergoing massive restructuring based upon genetic analysis. New classification schemes are being proposed and debated. These schemes break up the algae (protophyta) into different phylla, and even rearrange some families and genera. The same is occurring for the non-photosynthetic unicellular eukaryotes commonly referred to as the Protozoa ('proto' meaning earliest form of, and 'zoa' meaning animal).
The award winning evolutionary biologist Thomas Cavalier-Smith has been at the forefront of the changes in taxonomic structure for over twenty years. His reclassification of the protozoa is now well regarded among parasitologists and evolutionary biologists. Below is a 'Tree of Life' commonly used by parasitologists, and is based on the work of Cavalier-Smith.
Note that animals, plants and fungi are reclassified as Kingdom Opisthokont. This is due to the idea that animals, plants and fungi have genetic and metabolic commonalities that separate them from all other life (they are a monophyletic group).
Do you see how the genetic revolution has altered our appreciation of the diversity of life?
Why is it important for scientists to create a tree of life that is really based on genetic and metabolic relatedness?
While it is critical to recognize that the classification of protists is being rethought, it is important to understand some of the main protozoal groups. The proposed kingdoms most linked to Protozoa are:
- Rhizaria
- Excavata
- Amoebozoa
- Aveolates (not listed in above chart)
Daily Challenge:Take one of these protozoal groups and write about them. What are some of the species now held in this new grouping? Why are they now being considered related to each other, but different from other protists? Are there any species that are relevant to medicine, industry, food?
No comments:
Post a Comment