D Kingdom Protista Part 1

Kingdom Protista Evolution • Found ≈ 2 billion years ago • Hypothesised that they arose from endosymbiosis Classification 1. Unicellular or Multicellular o Unicellular  Can be colonial  several cells joined in a larger body with a diversion of labour o Multicellular  Has specialized regions for reproduction, photosynthesis; lacks tissue/organ differentiation 2. Nutrition o Autotrophic o Heterotrophic 3. Locomotion o Phylum Sarcodina: Pseudopodia o Phylum Ciliophora: cilia o Phylum Sarcomastigophora (Zoomastigina): flagella o Phylum Apicomplexa (Sporozoa): non-motile & parasitic Reproduction 1. Asexual o Binary fission o Some use multiple fission: produces more than 2 identical offspring 2. Sexual o Conjugation: forms bridge between 2 protists and exchange genetic material; cells then divide to produce 4 different offspring Phylums Phylum Sarcodina • Fresh water, marine environments, soil • Movement: pseudopodia: cytoplasmic extensions that reach out & pull forward • Cytoplasm has 2 parts o Ectoplasm: cytoplasm inside the cell membrane o Endoplasm: cytoplasm inside the cell • Eats by phagocytosis: engulfing the organism • Reproduces by binary fission • Cyst: hard shell for protection when conditions are poor

Phylum Ciliophora • Ponds, slow-moving streams containing plants & dead organic material • Structures & Functions o Pellicle: elastic protein protective layer surrounding the membrane o Oral Groove: tunnel lined with cilia to sweep food in o Mouth Pore: where food enters at the end of the tunnel o Gullet: forms food vacuole that goes towards enzymes & is digested o Macronucleus: large nucleus controls multiple copies of DNA for cell metabolism & growth o Micronucleus: small nucleus; exchange of genetic materials occur during conjugation • Asexual Reproduction o Binary fission o Micronucleus divides by mitosis to make 2 smaller nuclei o Macronucleus elongates and divides in half • Sexual Reproduction o Conjugation: form the bridge & exchanges genetic material 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

2 cells join forming a bridge macronucleus disintegrates micronucleus undergoes meiosis from a 2n (diploid) nucleus into 4 n (haploid) nuclei 3 of the 4 nuclei dissolve the remaining nucleus duplicates via mitosis to form a 2 nuclei 1 nucleus from each cell is exchanged old & new nucleus fuse to become a 2n nucleus cells separate 2n nucleus undergoes mitosis to form a micro and macro nucleus goes through asexual reproduction to form 2 identical offspring

Phylum Sarcomastigophora (Zoomastigina) • lakes, ponds • heterotrophic • some parasitic 1. Genus Trypanosoma o Blood of fish, amphibians, reptiles, birds, mammals o Carried from host to host by blood sucking insects 2. Genus Leishmania o Carried by sand flies in tropical/subtropical regions 3. Genus Giardia o Animal carriers contaminate water with their feces o Not fatal Phylum Apicomplexa (Sporozoa)

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Non-motile Carried through bodily fluids Absorb nutrients through blood Apical complex: organelles specialized for entering host cells & tissues Genus Toxoplasma Genus Plasmodium o Causes malaria o Life cycle: 1. 2. 3. 4. 5. 6. 7.

infected mosquito bites sporozoites enter blood stream & infect liver new cells emerge from liver called merozoites & infect red blood cells merozoites burst red blood cells releasing toxins merozoites form gametocytes another mosquito bites and ingests gametocytes gametocytes form gametes which fuses to form adult sporozoites