Lecture 13.1. Eukaryote traitsa. multicellularity: flexibility for environment: allow differentiation of cell type: adjustment to new environment. b. Sexual reproduction: increase speed of adaptation and genetic diversity.c. Compartmentalization: eukaryotic cell have organelles, andeach organelles have different role. - Membrane infolding of prokaryotic cell: more space(surface area) without increasing volume (size)- Engulfing other cell and hijacking their function- 1 stage; loss of the rigid cell wall leads to internal structure: allows much more plasma membrane. creates more surface within a cell without increasing size. Easier to exchange gases and nutrients exchange with thiner wall; endocytosis: bring things from outside to inside.- Ex) Nucleus, Endoplasmic reticulum (ER)2. Endosymbiosis- Aerobic bacterium insert to the ancestral eukaryotic cell,and it turns into mitochondria. - Photosynthetic bacterium (cyanobacteria) insert to it, and turns into chloroplast.- Examples of lateral transfer; horizontal transfer, which isnot usual for eukaryotes, but mitochondria and chloroplast.3. How are the protists profoundly paraphyletic?- The origin of eukaryotes begins with an ancestral protest.- Some protists are closed related to fungi, and some are closed to plant: don’t know where to put protists in the tree.- Protists are sometimes referred to as “microbial eukaryotes” to indicate that this is not a monophyletic group but a broader group of eukaryotes.4. Protist traitsa. Locomotion cilia: - Short flagella, wave water current. - Flagella: rotation of their body.- Pseudopods (bacteria)b. Cell surfaces- Plasma membrane- Extracellular material deposited on the membrane: protect protists from negative aspects of environment.c. Nutrition- Chemoautotrophy, photoheterotrophy- Photosynthesis:(1)Primary endosymbiosis: cynobacterium and ancestor of green and red algae.(2)Secondary endosymbiosis: Dinoflagellates or brown algae are offspring of the ancestor engulfing red or green algae. Thus, they are photosynthetic.d. Reproduction- Sexual- Asexual; binary fission5. Multicellularity.- Eukaryotic cells begin living in close association. Assoiation become colonies Individuals in colony take on different roles. Colony begins to function as an individual. Specialization of cell types Significant diversity6. SARA. Alveolates: stacks of vesicle, alveoli below their plasma membrane(1)Dinoflagellates- Unicellular marine organisms that usually can photosynthesize; secondary endosymbiosis, engulfing green algae.- Endosymbionts of corals: mutualistic- Luminous: twinkling effect in ocean at night.- Two flagella, long and short, within two groove, equatorial and longitudinal. Longer flagella propel and dinoflagellates move forward.- Plates of armor- It causes red tide, because of explosion of gymnopodium (dinofliagellates)(2)Apicomplexans- Spore forming parasitic found in animal- Apical complex: allow them to invade cell of the host.- Ex) Plasmodium-> malaria- Ex) Falciparum(3)Ciliates- Characterized by their movement; large number of cilia make water current, waving.- All heterotrophic- Ex) Paramecium sp.B. Stramenopiles: fine hairs extending from two flagella.(1)Brwon algaes- All multicellular- Due to this, protists are referred to as “microbial eukaryotes.”- Grow in relatively shallow water- Represent unique ecosystem: provide shelter and environment.- One of the largest photosynthetic “protists”- Ex) Giant Kelp(2)Diatoms- Sister taxa of brown algae; giant kelp- All unicellular, photosynthetic, unique double shell of silica: different from dinoflagellate.- Asexual and sexual reproduction- No flagella, except for male gamete.- Producers of energy- No luminous(3)Oomycetes- water molds: filamentous in from, non-motile- resemble fungi, but not truly fungi- parasites- Heterotrophic: external digestion: excrete digestive enzyme wait until food is digested pull in the digested food; suck- decomposerC. Rhizarians- All unicellular and aquatic- Long, thin, almost rigid, pseudopodia(1)Foraminiferans- Unicellular marine protists covered with the shell which are made of organic material. variety of species easily fossilized complexity of shell can make them look like multicellular, but the shell is really tiny.7. Excavates: A. Diplomonads and Parabasalids- diverse group - some groups do not have mitochondria; we consider it as thrive trait. - Most basal (ancestral) group in protists.- Eukaryote can live without mitochondria.- Giardia lives all natural water, need to filter it to drink water.B. Euglenids- unicellular- unique single flagella- have mitochondria- binary fission - loss of ability of sexual reproduction- heterotrophs or photoautotrophs: depend on the existence of sunlight: lifestyle flexibility.- Photosynthetic euglenids are thought to be risen from engulfing green algae; endosymbiosis.8. Archaeplastida; Plantae: Lecture 14.9. Amoebozoans (slime molds-> moving masses of living slime)- Lobe shape pseudopodia: locomotion; cytoplasmic streaming (flowing extension of cytoplasm); controlled by actin and myosin, and eatingA. Loboseans: classic amoebas- all unicellular- unlike slime molds, do not aggregate- live in the bottom of lake or stream- HeterotrophicB. Plasmodial slime molds/ Cellular slime molds- All multicellular- Plasmodial: huge single cell with multi-nuclei (no separation)- During vegetative state: only eating not reproducing- Individulas but highly colony- Combine and differentiate-> different structure- Early form of multicellularity- Grow slowly, and as long as there is enough food- If not enough food, resting state like dormant or reproductive.10. OpisthikontsA. Choanoflagellates- Its ancestral; ancestor to entire animal lineage- Ancestor branched off to fungi- Colonial choanoflagellates: Greatly resemble modern spongies from animals: Chanoflagellates and sponge aremohologous traits.B. AnimalsC.
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