Download Chapter 18 Protists Kingdom Protista Protist

Chapter 18
Protists
Kingdom Protista
Protist - unicellular eukaryotic organism.
• Classification of unicellular organisms has been difficult
o Because some organisms have characteristics common with more than a kingdom
Evolution of protests
• Lynn Margulis –said the first protests were formed by a symbiosis among several
prokaryotes
• Margulis noted that some organelles in eukaryotic cells were similar to structures in
prokaryotic cells
o ex: mitochondria & chloroplasts from bacteria or blue-green bacteria
o ex: flagella & cilia from many eukaryotic cells were similar to bacteria known as
spiroketes
The Endosymbiont Hypothesis
o prokaryotes lived within other monerans as endosymbionts
o they formed an efficient team
o eventually they lost their independence
o and became unable to live without one another
o the result was new organelles
Classification of Protists
o there are 3 types of protests groups.
o 1. Animal-like protests
o 2. Plant-like protests
o 3. Fungi-like protests
Animal-like Protists
4 phyla
1. Ciliaphora - have to have cilia
o a.k.a ciliates
o they can live solitary or in colonies
o ex: paramecium
p. 385
o Read and know all of the organelles and their functions
o Reproduction
o mostly asexual –binary fission
o “sexual” conjugation
o the macronucleus disintegrates.
o the micronucleus divides into four haploid nuclei (half genetic material).
o three of the four haploid nuclei disintegrates.
o remaining haploid nuclei divides again.
(result: 2 haploid micro-nuclei)
o two paramecia join and exchange a micronuclei
o two micro-nuclei fuse together, then split to form the macro-nucleus
2. Zoomastigina - have flagella
o known as flagellates
o ex: trypanasoma–causes African sleeping disease
3. Sporozoa - are non-motile = don’t move
o are all parasitic
o ex: plasmodium-protist that causes malaria
o reproduce asexually
4. Sarcodina - move by pseudopods. “false feet”
o ex: ameba p. 389
o ex: antemoeba-causes amebic dysentery
o -reproduce asexually
Harmful Relationships of Animal-like Protists
o most cause diseases
Useful relationships
o in the intestine of termites and/or roaches aid in digestion of cellulose (symbiotic
relationship)
o animal like protests are a major source of food for higher organisms (zooplankton)
o marine
o freshwater
p. 386