Lab 02 Algal Protists.08

Lab 02 Algal Protists.08 - Exercise 2: Survey of Protists I...

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1 Exercise 2: Survey of Protists I – The Algae BIOL 108: Week of January 21, 2008 I. Historical Perspective of Protist Taxonomy The Kingdom Protista was a taxonomic group first established by Ernst Haeckel in 1890. Prior to that time, organisms were either classified as ‘plant’ or ‘animal.’ Haeckel wanted to separate out the simpler, mainly unicellular organisms that he did not think were true plants or animals. Haeckel’s Kingdom Protista included bacteria, fungi, protozoans, algae and even the sponges. In Haeckel’s time, the fundamental difference between prokaryotic and eukaryotic cells was not fully understood. It wasn’t until 1938 that the bacteria (originally called ‘anucleates’) were removed and placed in their own Kingdom Monera. Remember that eukaryotic cells have membrane-bound organelles such as nuclei, mitochondria and chloroplasts. In 1959, the fungi were removed from the Protista and placed in their own Kingdom Fungi. This created a total of four kingdoms of eukaryotic organisms (the Animalia, Plantae, Protista and Fungi) thus establishing the five-kingdom system that was used for many years. Recent phylogenetic analysis of molecular data has resulted in a revision of the 5-kingdom system in favor of a 3-domain system . A domain is a relatively new taxonomic rank, higher than the kingdom level. On the basis of molecular data, the single prokaryotic Kingdom Monera has been split into two domains; the Archaea and the Bacteria. Within each of these domains microbiologists now recognize multiple kingdoms (see Fig. 27.12 in textbook). All eukaryotic organisms are currently classified under the Domain Eukarya . The limits of the eukaryotic kingdoms are the subject of much debate. The Animalia, Plantae and Fungi are relatively well-defined and appear to be monophyletic (‘one-lineage’) groups. The characteristics that distinguish most members of these groups are listed below: A. Kingdom Animalia : Animals are multicellular; they ingest their food, store excess carbohydrate as glycogen, have no cell walls, and pass through a blastula phase during embryological development. Their sexual life cycle is characterized as diploid-dominant. B. Kingdom Fungi: Fungi are generally multicellular, they absorb their food, store excess carbohydrate as glycogen, have cell walls made mostly of chitin, and reproduce by asexual and/or sexual spores. Their sexual life cycle is characterized as haploid-dominant. Key Objectives After completing this lab exercise, you should be able to… Define the term “protist” and explain why the original ‘Kingdom Protista’ is no longer considered monophyletic. List and describe the features that unite the informal group we call ‘algae’. Describe the major economic and ecological contributions of algae.
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This note was uploaded on 04/17/2008 for the course BIOL 108 taught by Professor Mchale during the Spring '08 term at Truman State.

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Lab 02 Algal Protists.08 - Exercise 2: Survey of Protists I...

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