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Pr otists BIO101 Fall 2011 Key Terms: Algae Protozoa Flagellate Ciliate Life Cycle Alteration of Generations Phytoplankton Gamete Mitosis Meiosis Cyst Algal Bloom Dinoflagellate Key Questions: • • • • Why are many algae not green? How are zygotic and gametic and sporic life cycles different from each other? How are they similar? What are some mechanisms that protists use to defend themselves? What are some helpful and harmful ways that protists impact humans? Lecture Outline: As a group, protists are hard to define; eukaryotic, usually microscopic, usually aquatic/marine not plant, not animal, not fungus Diploid and Haploid parts of the life cycle Mitosis: diploid diploid or haploid haploid Meiosis: diploid haploid Fusion: two haploids one diploid A Few of my Favorite Protists Chlamydomonas – classed as a Flagellate due to 2 flagella Life Cycle: Haploid cells develop into gametes Diploid zygote is dormant. Meiosis to make 4 mature cells Diatoms – usually unicelluar, photosynthetic highly abundant, espcially in the ocean as phytoplankton Life Cycle: Gametes formed by meisos fuse to make a zygote that grows by mitosis Red and Brown Algae – typically multicellular. Photosynthetic. How can they be photosynthetic and not green? Sporic Life Cycle (‘Alteration of Generations’) Mature seaweed makes haploid spores male and female gametophytes grow. eventually release gametes gametes fuse to get sporophyte – grows to make mature seaweed Paramecium – freshwater ciliates. Heterotrophic two distinct types of nuclei in ciliates -- micronuclei and macronuclei micronuclei are diploid; macronuclei are roughly polyploid (but copy varies by gene) micronuclei don’t express genes; macronuclei do typically reproduce asexually but can do a pseudosexual mating Cryptosporidium parvum infects humans via a diploid cyst Pfiesteria – heterotrophic flagellate. Dinoflagellate (flagella and two armor plates) associated with harmful algal blooms. Primarly caused by fertilizer runoff appears to make a toxin that injures or kills fish major outbreaks in 1990s in Chesapeake Bay impact on humans? unclear Plasmodium falciparum – one of four species in the Plasmodium genus that cause malaria depdenent upon Anopheles mosquitoes drug treatment and resistance Trypanosomes – causes sleeping sickness in humans. Antigenic variation (bait and switch) to evade the immune system of the host
