Bio 201 F11 Lect 13 (True) v3nr

Bio 201 F11 Lect 13 (True) v3nr - Biology in the News[see...

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Unformatted text preview: Biology in the News [see folder on BB] •  •  •  •  •  •  •  •  behavioral biologists are studying copying behavior in orangutans to understand similar behaviors in humans (and other primates) and their rela=onships to sociality and intelligence orangutans are classified as "solitary but social" ‐ meaning that they only spend very liAle of their lives associated with other individuals aBer the mother‐offspring rela=onship is completed 13 orangutans living in cap=vity were studied as to how informa=on was transferred from one individual to the next a box with a reward was presented; the reward could be accessed by two different means (slide or liB doors) a mother figured out one way and was observed by her son, but she prevented him from touching the box; example of general finding that orangutans were very good at observing/copying but generally, it has been found in this and other studies, that they will only copy when it serves a purpose (i.e. in this case the orangutans could always figure out the other way and get a treat; there was no reason to do it by copying others) in humans, on the other hand, copying can be an important aspect of our social behavior, which is much more advanced than orangutans ‐ humans will copy even if it unnecessary, as long as it has social value ("belonging") "intelligence" hence has two different defini=ons, depending on sociality hAp://www.nsf.gov/news/special_reports/ science_na=on/copycats.jsp?WT.mc_id=USNSF_196 0‐5 6‐10 11‐15 16‐20 21‐25 26‐30 31‐35 36‐40 41‐45 46‐50 51‐55 56‐60 61‐65 66‐70 71‐75 76‐80 81‐85 86‐90 91‐95 96‐100 # of students Bio 201 Fall 2011 mid term 1 90 80 70 60 50 40 30 20 10 0 score average = st. dev. = median = 69.36 16.34 71.57 bonus ques=ons •  worth 1 pt (out of 35) each •  e.g. if you got 25 right on the main test (1st 35 ques=ons) and all 3 bonus ques=ons right, your score would be (25+3)/35 = 28/35 = 80% –  we are checking and recalcula=ng the scores to make sure we got this right for exam 1 (see BB and lecture on Friday) Endosymbio=c theory hAp://en.wikipedia.org/wiki/Image:Merezhkovsky_K_S.jpg •  Mitochondria evolved from ancient bacteria •  Chloroplasts evolved from ancient photosynthe=c bacteria or photosynthe=c eukaryotes •  Originated by Konstan=n Mereschkowski in 1905 •  Revived and inves=gated by Lynn Margulis in the 1960s‐1970s •  Was once thought to be a strange idea •  Ini=al evidence was structural •  DNA evidence sealed it hAp://en.wikipedia.org/wiki/Image:Lynn_Margulis.jpg hAp://porpax.bio.miami.edu/~cmallery/255/255hist/mcb1.15.cytoskeleton.jpg cytoskeleton •  made of monomers that can rapidly polymerize and depolymerize –  ac=n, tubulin, intermediate filament (IF) proteins •  Important for: –  Mo=lity •  Pseudopodia, cilia, flagella –  Chromosome movement during mitosis and meiosis hAp://fig.cox.miami.edu/~cmallery/150/life/meiosis.pics.jpg Cytoskeleton components have been discovered in prokaryotes: i.e. prokaryotes have their own form of cytoskeleton in the last decade it has been discovered that bacteria and archaea have homologs to actin, tubulin, and intermediate filament (IF) proteins (not shown) bacteria also have a unique group of proteins: MinD and Soj that are not present in eukaryotes (bacterial cytoskeleton is more wellknown than achaea cytoskeleton, currrently) Thanks to Jared Postoia for the reference! how do bacteria use their cytoskeleton? •  in bacteria, cell wall is known to be the primary determinant of cell shape –  cytoskeletal elements may help regulate the forma=on of cell wall structures into par=cular shapes (e.g. rods, helices) •  bacterial cytoskeleton also plays a role in: –  cell polarity –  par==oning of the circular “chromosome” (genome) during binary fission http://www.international.inra.fr/research/ some_examples/ internal_skeleton_determines_bacterial_sh ape therefore we need to rethink the role of the cytoskeleton in eukaryo=c evolu=on •  common ancestor of all 3 domains had ac=n and tubulin –  would be useful to find out more about cytoskeleton in archaea •  eukaryo=c cytoskeleton func=ons in force genera=on in mul=cellular =ssues (e.g. muscle) and interacts with molecular motors; the interac=ng components (kinesin, dynamin, myosin) have not yet been found in prokaryotes •  loss of the prokaryo=c cell wall involved evolu=onary opportuni=es for more diverse func=ons of the cytoskeleton in ancestral eukaryotes??? Bacterial vs. Eukarote flagella hAp://en.wikipedia.org/wiki/Image:Flagellum_base_diagram.svg •  Bacterial flagellum –  Single “fibril” composed of flagellin (protein) –  Hook and basal body drive mo=on •  Eukaryote flagellum –  Independently evolved –  Enclosed by plasma membrane –  9 pairs of microtubules surround 2 microtubules in the center hAp://fig.cox.miami.edu/Faculty/Dana/flagellum.jpg a brief review •  Diploid and haploid •  Mitosis: diploid parental cell duplicates its DNA (chromosome(s)) and divides once to yield two iden=cal daughter cells –  Haploid cells can also duplicate via mitosis •  Meiosis: diploid parental cell duplicates its DNA (chromosome(s)) and then goes through two divisions to yield four non‐iden=cal haploid progeny cells (gametes) Eukaryote reproduc=ve diversity: conjugaBon •  One group that does this: Paramecia see LIFE 9th ed. Fig. 27.12 Macronucleus ‐ used for running the cell Micronucleus ‐ used for meiosis, reproduc=on Mul=cellular eukaryote reproduc=ve diversity: alterna=on of genera=ons between haploid and diploids •  One group that does this: land plants and many other mul=cellular photosynthe=c eukaryotes gametophyte sporophyte see LIFE 9th ed. Fig. 27.13 Eukaryote reproduc=ve diversity: alterna=on of genera=ons: isomorphic life cycle •  One group that does this: many chlorophytes such as the sea leAuce Ulva lactuca Isogamy: Isogamy: gamete cells look the same in shape and form. Angiogamy: gamete cells differ in size and form. The male gamete is smaller, and the female gamete is larger. see LIFE 9th ed. Fig. 27.14 male and female gametes are not different (this is the case for U. lactuca but not all isomorphic species; some have Anisogamy) Eukaryote reproduc=ve diversity: alterna=on of genera=ons: haplon=c life cycle •  One group that does this: many chlorophytes such as Ulothrix see LIFE 9 ed. Fig. 27.15 th hAp://bo=t.botany.wisc.edu/images/130/ Chlorophyta/Ulothrix_130_.jpg Eukaryote reproduc=ve diversity: what are we? •  Diplon=c life cycle hAp://en.wikipedia.org/wiki/Image:Game=c_meiosis.png Now let’s… •  Examine what is known about the evolu=onary rela=onships of major eukaryote groups •  Map two important characters onto this phylogeny –  photosynthesis/endosymbiont events –  mul=cellularity •  Point out some important organisms Chromalveolates Cryptophyte clade not shown 3˚ 2˚ EndosymbioBc events leading to chloroplasts (probably not all of them) 2˚ Plantae Excavates Unikonts Rhizaria Opisthokonts Amoebozoans 2˚ 1˚ see LIFE 9th ed. Fig. 27.1 EndosymbioBc event leading to mitochondria MulBcellularity Unikonts Chromalveolates see LIFE 9th ed. Fig. 27.1 Plantae Excavates Rhizaria Opisthokonts Amoebozoans two strange terms •  unikonts – “one” + “pole” flagellum – Consists of the opisthokonts plus the amoebazoans •  opisthokonts (“behind”+”pole”[flagellum]) –  i.e. suggests that the flagellum is used for propulsion Diatoms Chromalveolates Plantae Excavates Rhizaria Unikonts Opisthokonts Amoebozoans see LIFE 9th ed. Fig. 27.1 Abundant in the oceans, and fresh water Cell walls contain silicon, preserve well as fossils Foraminiferans Chromalveolates Plantae Excavates Rhizaria Unikonts Opisthokonts Amoebozoans see LIFE 9th ed. Fig. 27.1 Calcium carbonate shells Abundant in oceans Cause of limestone deposits in Earth’s crust Dinoflagellates Chromalveolates Plantae Excavates Rhizaria Unikonts Opisthokonts Amoebozoans see LIFE 9th ed. Fig. 27.1 Photosynthesizers, vital primary producers in the oceans Unicellular, with two flagella, one in each groove Some are symbionts of corals Trypanosomes Chromalveolates Plantae Excavates Rhizaria Unikonts Opisthokonts Amoebozoans see LIFE 9th ed. Fig. 27.1 see LIFE 9th ed. Table 27.2 Plasmodium, the malaria parasite Chromalveolates Plantae Excavates Rhizaria Unikonts Opisthokonts Amoebozoans meiosis Figure 27.9 Life Cycle of the Malarial Parasite (A) Like many parasitic species, the apicomplexan Plasmodium falciparum has a complex life cycle, part of which is spent in mosquitoes of the genus Anopheles and part in humans. The sexual phase (gamete fusion) of this life cycle takes place in the insect, and the zygote is the only diploid stage. (B) Encysted Plasmodium zygotes (artificially colored blue) cover the stomach wall of a mosquito. Invasive sporozoites will hatch from the cysts and be transmitted to a human, in whom the parasite causes malaria. • Zygote (in mosquito) ‐ very brief diploid stage • Sporozoites ‐ haploid • Gametocytes (in human), get transferred to the mosquito and develop into gametes, undergo fusion to form the zygote Fungi Chromalveolates Plantae Excavates Rhizaria Unikonts Opisthokonts Amoebozoans Lae1porus see LIFE 9th ed. Fig. 27.1 Fungal mutualism: two major modes •  Mutualism is a symbio=c rela=onship that benefits both partners –  (by itself, symbiosis means a close, long‐term associa=on) •  Lichens –  Fungal associa=on with a photosynthe=c microbial organism (a unicellular green alga or cyanobacterium) •  Mycorrhizae (pl., sing.=mycorrhiza) –  Associa=ons between fungi and plant roots Lichens can survive in many harsh environments •  Fungal component ‐ most are from the ascomycete clade (a clade is a monophyle=c group) •  Most grow very slowly Anatomy of a foliose lichen; soredia •  Many species (>15,000) (sing. soredium) have both components and disperse via wind. –  Poorly understood A crustose lichen A foliose lichen A frui=cose lichen Reproduc=on also occurs by fragmenta=on Micorrhizal fungal associa=ons with plants are ubiquitous •  Fungi help plant roots absorb water and nutrients (minerals) –  Greatly adds to surface area –  Vital for most plants •  Fungus obtains organic compounds from the plant •  Two types –  Ectomycorrhizae •  Fungi wraps around root –  Arbuscular mycorrhizae •  Hyphae enter root cells (like haustoria of fungal parasites) Endophy=c fungi (endophytes) •  Live on plants above the ground •  Provide many benefits to plants (e.g. resistance compounds) but some are pathogens •  Some live within the leaves and other =ssues Taxomyces andreanae, an endophyte found in the bark of the Pacific Yew tree, was the original source of the an=cancer drug, taxol. ...
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This note was uploaded on 12/16/2011 for the course BIO 201 taught by Professor True during the Fall '08 term at SUNY Stony Brook.

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