The+origins+of+New+Eukaryotic+Diversity

Later in Time....

The origins of New Eukaryotic Diversity
The majority of today's organisms that inhabit the Earth are classified as eukaryotic. Their cells are much more complex when compared to prokaryotic cells. They contain cytoplasmic organelles that help the cells to carry out metabolic activities. To most biologists, the determining feature between the two cells is the presence of a nucleus. Many students tend to associate eukaryotic cells with only animal and plant cells, but there was a much larger class of organisms that originated from the early prokaryotes**__//-those are the protists.//__** (Surprised?)

The "Protists"
Protists are microscopic organisms that are usually unicellular. However, "protist" is just an informal name for the many organisms that fit these simple criteria. Many of these organisms differ from each other,varying from one another. These inaccurate classifications have led to a crumbling the taxonomic system that is thought to be beyond repair. Many are just placed here because they are not animals, fungi, or true plants. They carry out aerobic respiration using mitochondria, but some even lack mitochondria to begin with! (Did you catch that?) They are mainly photoautotrophs that contain chloroplasts and heterotrophs. Euglena is an example of mixotrophs which combine heterotrophic nutrition and photosynthetic reactions. The following link shows a diagram of the parts of the //Euglena viridis//. [| http://biocab.org/files/Euglena_Eng.jpg]