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101 Cards in this Set
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- Back
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Domain archaea |
Prokaryotic - structurally, biochemically, molecularly, adaptively different from typical bacteria: - withstand harsher, more unusual conditions than bacteria - external cell wall lacks peptidoglycan (main diff. From bacteria) Examples: methanogens - aerobic - produce methane gas (methanococcus) - live in peat bogs, guts of herbivores and termites Halophiles: salt tolerant (halobacterium) - live in great salt lake, and dead sea |
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Domain bacteria |
Have external wall composed of peptidoglycan (chains of sugars connected by amino acids; form sheets) outside cell membrane - protects cell from outside environment, breaking apart when it takes on water, and maintains cell shape (coccus: round or rod: e coli) |
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External cell wall patterns in bacteria |
Gram positive bacteria: have a thick peptidoglycan external cell wall (several layers) - cell wall stains blue during gram staining Gram negative bacteria: have a thing peptidoglycan external cell wall (one layer) - cell wall stains pink during gram staining |
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Capsule |
Structure outside the external cell wall (gram positive) or outer membrane (gram negative) Capsule functions: - protects against phagocytosis: engulf mentioned by white blood cells - allows bacteria to stick to surfaces - provides bacteria with ability to cause disease: virulence |
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Flagella, fimbriae, pili |
Many bacteria have appendeges on cell surface Flagella: organelles of motion; move cell toward or away from stimulus Fimbriae (pili): allow bacteria to stick to surfaces and each other Sex pili: connects 2 bacteria; 1 bacterium tansfers DNA to the other - not reproduction but gene transfer |
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Cell membrane |
protects cytoplasm, regulates material transport, responds to stimuli - composed of phospholipid bilayer and proteins - no cholesterol in prokaryote cell membrane |
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Cytoplasm |
fluid inside cell containing DNA and ribosomes - nucleoid: location of single, circular, double stranded pieces of DNA * no nuclear membrane surrounding prokaryotic DNA - some bacteria have plasmids: small pieces of DNA outside of nucleoid *plasmid genes can provide resistance to antibiotics or produce toxins - ribosomes: site of protein synthesis in all cells * similar to eukaryotic ribosomes - smaller |
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Endospores - Bacillus |
thick walled - endospore forms when environment becomes harsh or stressful - survive heat, drying, toxins, low nutrients - endospores released into the environment - germinate when conditions improve - endospores are the most resilient structure in nature - found in amber (fossil resin) and pyramids |
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Bacteria have 3 patterns of symbiotic relationships with eukaryotes |
Commensalism: commensal species benefit from relationship but do not harm host - EX: normal flora - species grow on the body at all times; Staphylococcus aureus on skin Mutualism: both species benefit EX: normal flora contribute to digestion - E. coli synthesize vitamin K, some B vitamins inhibit competitors in large intestine Parasitism: parasitic species harm the host; cause disease |
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10 factors contributing to the spread of disease |
Antibiotic resistance in bacteria: due to genetic mutations and overuse of antibiotics - MRSA Fecal contaminated water - cholera, typhoid Undercooked food - salmonella causes food poisoning Lack of or improper hand washing Increase in animal species maintaining disease agent in nature: Reservoir - birds, mammals (rodents), insects - ill humans function as reservoirs - asymptomatic carriers: people are infected but do not show symptoms of illness Increase in species transmitting disease agent from host to host - vector - fleas, ticks, lice, mosquitos, flies - ticks spread bacteria causing Lyme disease, Rocky Mountain spotted fever - overuse of pesticides has increased resistance in many insect groups Unsafe sex - chlamydia: intracellular parasite; most common bacteria STD in US Biological Weapons: anthrax, endospores Global Warming: may increase survival and distribution of reservoirs and vectors away from tropics Pet Kisses |
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Life Cycles |
Sexually reproducing organisms have 2 stages during their life - haploid and diploid - Haploid phase (n): 1 copy of each chromosome - haploid spores or gametes (sperm or egg) form by meiosis - Diploid phase (2n): 2 copies of each chromosome - 2 haploid gametes fuse to form a zygote - 1st diploid cell - diploid phase divides by meiosis to form haploid spores or gametes 3 life cycle patterns in sexually reproducing organisms: zygotic, sporic, gametic |
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Zygotic life cylce |
Dominant haploid phase Zygote is the only diploid phase in life cycle - zygote divides by meiosis to form haploid cells and gametes Characteristic of fungi and chlamydomonas - considered to be most primitive life cycle |
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Gametic life cycle |
Dominant diploid phase Gametes (sperm and egg) only haploid phase - 2 haploid gametes fuse to form zygote - zygote divides by mitosis to form multicellular diploid body Gametic life cycle considered to be the most advanced life cycle - characteristic of animals |
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Sporic life cylce
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all plants and most algae Characterized by 2 alternating, multicellular forms during life cycle - gametophyte and sporophyte - gametophyte: haploid; produces gametes by mitosis * gametes fuse from zygote * zygote develops into diploid sporophyte - sporophyte: produces haploid spores by meiosis * spore develop into haploid gametophytes |
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2 life cycle patterns of the sporic life cycle |
Some are isomorphic: sporophyte and gametophyte stages look identical ( ULVA) Most are heteromorphic: sporophyte and gametophyte stages look very different - one is the dominant stage: larger, longer lived, more visible - other is the reduced stage: smaller, shorter lived, less visible - some have dominant gametophyte, reduced sporophyte (mosses, Porphyra) - Others have dominant sporophyte, reduced gametophyte ( most plants, Sargassum) |
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Mitosis |
- does not change chromosome number - haploid cell forms 2 haploid cells - diploid cell forms 2 diploid cells |
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Meiosis |
divides chromosome number in half - diploid cell forms haploid cells |
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Starr arranges the original Kingdom Protista into 7 groups in the Domain Eukarya |
- excavates - rhizaria - alveolates - stramenopiles - red algae - green algae - amoebozoans |
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Protists |
- Protists are eukaryotic and mostly unicellular: cannot be characterized as true animals, plants or fungi - group relationship based on molecular and morphological evidence |
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Animal Protists |
- Animal protists are unicellular and heterotrophic: usually referred to as protozoans * distinguished by organelles of motion (flagella, cilia or pseudopodia) * change form during life cycle: many have more than 1 host (cyst: infective stage; ingested by host) |
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Plant protists |
photosynthetic - probably derived by secondary endosymbiosis - primary endosymbiosis: photosynthetic cyanobacterium engulfed by heterotrophic eukaryote * evolve into eukaryotic photosynthetic red and green algae - secondary endosymbiosis: red and green algae engulfed by other heterotrophic eukaryotes * forms dinoflagellates, diatoms, brown algae, euglenoids - each distinguished by photosynthetic pigments, storage products, external cell wall |
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Fungus protists |
resemble higher fungi - some parasitic - characterized by hyphae filaments and sporangia |
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Slime Molds |
included with amoebas but not directly related to any animal or fungus group - animal like because it moves through environment - fungus like because it produces sporangia and spores |
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Excavates - group one |
Characterized by flagella and bilateral symmetry - Giardia - Euglena - Trypanosoma |
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Giardia |
Excavate Adapted to live in the animal intestinal tract - heart shaped cell with 2 nuclei and several flagella * cysts transmitted host to host by fecal contaminated water, food or personal contract (cause of hiker's diarrhea) |
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Euglena |
Excavate Derived by secondary endosymbiosis with green algae - exhibits plant and animal characteristics * plant like: chloroplasts; photosynthetic in light * animal like: heterotrophic with flagella; ingests prey; survives in dark - red eyespot: directs Euglena to or away from light |
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Trypanosoma |
Excavate Flagellated - Causes african sleeping sickness in humans and domesticated animals (cattle) * lion, hyena, antelope are natural reservoirs - other wild animals unaffected (spread host to host by tse tse fly: vector) - trypanosoma releases neurotoxins into blood: eventually affects CNS * causes sleep disorders (sleep day, awake at night), paralysis, death |
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charophytes - chara |
living form considered to be most closely related to green plants share characteristics with both green algae and green plants |
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Amoebozoans |
amoeba, slime molds |
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amoebozoans - protozoans, amoeba, chaos |
group most closely related to true fungi and true animals - molecular evidence have pseudopodia for movement and feeling |
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Slime molds |
no direct relationships to any other groups including fungi Plasmodial (true) slime molds - physarum - plasmodium: growth form; large, multinucleate cell without cross walls - plasmodium moves around environment when conditions are favorable * plasmodium ingests bacteria, yeast and fungal spores * cytoplasmic streaming distributes nutrients throughout mass - plasmodium reproduces sexually when environment becomes unfavorable * forms stalked sporangia and produces spores * spores reform large multinucleate plasmodium - resumes feeding |
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Kingdom fungi, choanoflagellates, kingdom animalia |
choanoflagellates - living group considered to be the most closely related to kingdom animalia |
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Charophytes - chara |
Living form considered to be most closely related to green plants. - share characteristics with both green algae and green plants |
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Amoebozoans |
Protozoans - amoeba, chaos - group most closely related to true fungi and true animals: molecular evidence * have pseudopodia for movement and feeding |
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Slime molds |
Amoebozoans group No direct relationships to any other groups including fungi - plasmodial (true slime mold): physarium * Plasmodium - growth form; large, multinucleate cell with out cross walls - Plasmodium moves around environment when conditions are favorable * Plasmodium ingests bacteria, yeast and fungal spores: cytoplasmic streaming distributes nutrients through mass - Plasmodium reproduces sexually when environment becomes unfavorable: forms stalked sporangia and produces spores * spores reform large multinucleate Plasmodium - resumes feeding |
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Kingdom fungi, choanoflagellates, kingdom animalia |
Choanoflagellates - living group considered to be the most closely related to kingdom animalia |
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Primary endosymbiosis |
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Fungi |
Molecular evidence shows fungi more closely related to animals than plants or protists - animals and fungi thought to have diverged about 1.5 bya (oldest fossil fungus about 460 million years old) - amillaria: tree fungus; reported to be the largest organism on earth * filaments extend more than 1500 acres (estimated to be 1900 years old) |
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Secondary endosymbiosis |
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Characteristics of fungi |
Heterotrophic - don't ingest food directly - secrete enzymes that break down substances outside of cell: nutrients absorbed into cell * saporophytes - break down dead organisms, decaying organic matter * parasites - infect and feed on host cells - 2 primary growth forms: Hyphae and yeast * 3 forms of hyphae - hyphae cell walls composed of chitin: nitrogen containing polysaccharides also found in insect exoskeletons |
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Hyphae growth form in fungi |
Mycelium - mass of hyphae (filaments) - composed of lower and higher fungi - 3 forms of hyphae: stolons, rhizoids, vertical hyphae |
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Lower fungi |
Hyphae have no intercellular cross walls - forms 2 multinucleate, haploid cell * cytoplasm continuous throughout mycelium - phylum zygomycota - rhizopus |
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Higher fungi |
Have cross walls with pores - hyphae appear multicellular, but are not * 1 nucleus in each compartment - phylum ascomycota, phylum basdiomycota |
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3 types of hyphae |
Stolons: Hyphae that grow horizontally along surface Rhizoids: hyphae that anchor to substrate and absorb nutrients Vertical hyphae produce sporangia or conidia: produce asexual spores - sporangia: produce enclosed spores (phylum zygomycota) - conidia: produce exposed spores (phylum ascomycota, phylum basidiomycota) |
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Yeast growth form |
Single cells that normally do not form hyphae - reproduce by budding (mitosis): 1 cell divides to form 2 cells |
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3 phases to sexual reproduction in fungi |
Cytoplasms from 2 different hyphae (individuals) fuse - new hypha contains 2 different haploid nuclei from each individual Haploid nuclei fuse to form zygote - only diploid phase; zygotic life cycle Zygote divides by meiosis to form haploid spores - zygomycota: zygospore forms spores; rhizopus - asomycota: zygote forms 8 ascospores in ascus; cup fungi - basidiomycota: zygote forms 4 basidiospores in basidium; mushrooms |
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Fungi groups characterized as lower fungi, higher fungi or deutermycota
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Lower fungi - chytrids, zygomycota (primitive) Higher Fungi - clomeromycota, asomycota and basidiomycota Deutermycota - imperfect fungi; species known only from asexual forms - cannot be placed in a phylum without sexual reproduction haracteristics *histoplasma - only produces yeast form |
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chytrids |
considered to be the oldest fungus group - only fungus that produces flagellated spores and gametes - chytrids: implicated in decline of frog populations * may represent new disease for frogs - no immunity in frogs |
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Zygomycota |
Conjugation fungi; rhizopus; black bread mold - asexual reproduction by sporangia: produce enclosed spores - sexual reproduction: conjugation * different individuals and nuclei combine - forms diploid zygospore *zygospore divides by meiosis to form haploid spores * haploid spores form new haploid hyphae |
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Glomeromycota |
Mycorrhizal fungi - form mutualistic, symbiotic associations with plant rocks * plants provide organic nutrients for fungi * fungi enhance ion, mineral, water uptake into plant roots - 2 forms of mychorrhizae * endomycorrhizae ((arbuscular) - hyphae grow into root cells - form arbuscules (hyphae branches) inside root cells * entomycorrhizal fungi - cover surface of root and grow between by not into root cells |
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Azcomycota |
Sac (cup) fungi; yeasts, mildews, molds, morels and truffles - asexual reproduction by conidia: produce exposed spores - sexual reproduction: ascus formation *zygote forms 8 haploid ascospores in each ascus - yeasts: single celled; reproduce by budding * saccharomyces cerevisiae - bakers (brewers) yeast *ferments glucose to ethanol and CO2 - used to make bread, beer and wine * candida albicans: part of normal flora of skin, vagina and mouth in humans * opportunistic fungi - overgrowth leads to yeast infection (vaginitis), oral thrus * infections result from broad spectrum antibiotics, tight pants - molds: * penicillium - source of penicillin antibiotic (discovered by alexander fleming) *aspergillis - produces aflatoxins on poorly stored peanuts and cereal grains (may cause liver disease in humans and domesticated animals) |
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Phylum basidiomycota |
club fungi; mushrooms, toadstools - asexual reproduction by conidia: produce exposed spores - sexual reproduction: basidium formation * zygote forms 4 haploid basidiospores - mushroom: fruiting body; composed of cap with gills and stalk * agaricus - edible, store mushroom * amanita - orange/ red cap with white spots; poisonous |
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Role of Fungi in ecosystem |
Commensalistic, mutualistic or parasitic with other organisms - Decomposers - Lichens |
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Decomposing fungi |
saprophytic; mutualistic - breakdown organic matter and recycle nutrients back to soil |
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Lichens |
Mutualistic between fungi and photosynthetic green alga or cyanobacterium - lichen form - green algae or cyanobacteria benefits fungus - fungi benefit green algae or cyanobacteria - lichens mostly reproduce asexually * Form soredia - clumps of hyphae with algae or cyanobacteria |
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Lichen form |
Crustose: crust like Foliose: leaf like Fruticose: shrub like |
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Green algae or cyanobacteria benefits fungus |
- Produce organic compounds by photosynthesis - cyanobacteria also fix atmospheric nitrogen |
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Fungi benefit green algae or cyanobacteria |
- Fungi produce toxic compounds that deter herbivores - fungi retain water and minerals - fungi secrete enzymes to absorb nutrients |
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Some fungi form mutualistic relationships with animals |
Leaf cutter ants prepare fungus farms in nest - ants bring leaves to fungi - fungi break down leaves to form used by ants - ants protect fungi - fungi obtain nutrients from leaves |
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Fungi mostly parasitic on plants |
Produce parasitic hyphae; haustoria - chestnut blight: introduced around 1900 from Asia; wind disperses spores - oak wilt disease: hill country |
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Some fungi parasitic on humans |
Dermatophytes: ring worms - cause skin infections: athletes foot, jock itch, scalp itch * epidermophyton causes most ringworm infections (90% cases in men - spread by direct contact; women resistant) * athletes foot results from wearing shoes, not cleaning and drying feet (does not occur when people go barefoot) Respiratory infections: - histoplasma: causes histoplasmosis; most common fungus respiratory infection * fungus grows in soils contaminated with bird fecal matter - inhaled spores (symptoms resemble TB) - Histoplasma deuteromycota; known only from asexual form |
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Land plants |
Multicellular, photosynthetic, terrestrial - 290,000 living species - oldest fossil vascular plants - Rhynia and Cooksonia; 450 million years old * branching photosynthetic stems - true leaves or true roots * seedless - produce spores in sporangia * cylinder of conducting tissue in stem moves water and substances throughout plant |
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Charophyta - chara; green algae |
Multicellular group thought to be the closest living, photosynthetic relative of land plants - evidence based on chloroplast and nulcear DNA, morphology and biochemistry Charophyta share characteristics with both land plants and green algae - photosynthetic with chlorophyll a and b - starch storage product - cellulose external cell walls Charophyta exhibits characteristics found in land plants but are NOT found in green algae - cell plate: support new cell wall that forms between 2 new cells during cell division - plasmodesmata: connects cytoplasms of adjacent cells through cellulose walls |
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Land plants characterized by 6 adaptations for living on land |
These do NOT occur in charophyta - vascular tissue - specialized meristems - multicellular haploid and diploid alteration of generations in life cycle - leaves with stomata and waxy cuticle - specialized leaves from sporagnia that produce spores - true roots |
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Vascular tissue |
Conducts water and nutrients throughout plant - xylem: conducts water and minerals up from roots to leaves - phloem: conducts sugars, other nutrients from leaves throughout plant |
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Specialized meristems |
Cells that divide by mitosis to increase lenth and diameter of plant body - apical meristems: increase length of plant body and shoot tips and root tips - lateral meristems: increase diameter of plant body |
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Multicellular halpoid and diploid alternation of generations in life cycle - 2 stages |
Haploid gametophyte (male and/or female) produces gametes (sperm and/or egg) by mitosis - male produces sperm in antheridium * sperm moves to egg by flagella, wind of animals - female produces large non motile egg in archaegonium * sperm fertilizes egg in archaegonium - forms diploid zygote - zygote forms embryo: embryo forms multicellular diploid sporophyte Diploid sporophyte produces sporangia that produce haploid spores by meiosis - haploid spores form haploid gametophytes |
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Leaves with stomata and waxy cuticle |
Leaves capture sun energy for photosynthesis - stomata: pores through epidermis and cuticle * stomata open and close to allow gas exchange and control water loss - waxy cuticle: protects exposed surfaces from dehydration and herbivores - leaves characterized as microphylls or true leaves |
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Michrofylls |
Primitive leaf, outgrowth of stem with 1 vascular trace (vein) - equisetum, Lycopodium, Selaginella = only living species with microphylls True leaves produced by all other land plants - branching vascular system |
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Specialized leaves form sporangia that produces spores |
Lycopodium, ferns, Equistum form 1 sporangium type that produces 1 spore type - spore forms gametophyte with both antheridia and archaegonia * gametophyte produces sperm and egg Selaginella and higher plants produce 2 different sporangium types, 2 different spore types - small pores form male gametophytes with antheridia: produce sperm - large spores form female gametophytes with archagonia: poduces egg Sporangia producing leaves form clusters: strobilus (cone) or flower |
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True roots |
Absorb water and minerals from soil - anchors and stabilizes plant - allow plant to grow taller |
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Non vascular plants |
No vascular tissue to conduct water and nutrients throughout plant - bryophytes: non vascular, seedless, all lack true roots and true leaves * mosses and liverworts |
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Vascular plants |
Vascular tissue conducts water and nutrients throughout plant lycopods and ferns: vascular, seedless; produce spores - most have true leaves and true roots * lycopodium, selaginella, ferns, equisetum Gymnosperms and Angiosperms: - seed producing vascular plants * most advanced plant group; 90% of land plants - gymnosperms: vascular; produce seeds in cones; no flowers or fruits * gingko, cycads, gnetophytes, conifers - angiosperms: vascular; produce seeds in fruites; no cones * all flowering plants - monocots and dicots |
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Bryophytes |
Non vascular, seedless: mosses and liverworts - 1st land plants: dominant during first million years of plant evolution (475 mya) - evolved in most terrestrial habitats: dependent on water to survive - thin external cells walls: limits size - photosynthetic with stomata: no true leaves - no vascular conducting tissues: water, minerals absorbed across surface - rhizoids: root like, anchor plant but do not absorb water - produce flagellated sperm that swim to egg |
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Bryophytes: mosses |
2 multicellular stages in life: polytrichium, sphagnum (peat) moss - dominant haploid gametophyte * produces gametes by mitosis * sperm in atheridia * egg in archegonia * flagellated sperm fertilizes egg in archaegonium: forms zygote - zygote forms small, short lived, diploid sporophyte * sporophyte capsule - contains sporangium * haploid spores form in sporangium * spores released through openings in operculum of capsule when capsule dries - hapolid spores form filaments that develop into haploid gametophytes Peat moss used as fuel and moisture retaining agent in cultivated plant soil |
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Liverworts |
Marchantia; seedless, non vascular - simpler than mosses: no stomata; probably older than mosses - dominant haploid gametophyte: produces sperm or egg - flagellated sperm fertilize egg: forms zygote - zygote forms very small, diploid sporophyte - haploid spores form in sporangium capsule - liverwort gametophytes can reproduce asexually by gemma cups - gemma cups produce new gametophytes |
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Lycopodium, selaginella, ferns, equisetum |
Most primitive living vascular plants - ancestors dominant in carboniferous forests (390 mya) - all contribute to coal deposits - lepidodendron: club moss; large trees more than 40 meters tall, 2 meters in diameter |
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Lycopodium and selaginella - club mosses |
- dominant sporophyte with true roots and small gametophyte - microphylls: primitive photosynthetic leaves with 1 vascular trace - sporangia bearing leaves form strobilius: cone like structure; produces spores - cylinder of vascular conducting tissue in stem: xylem and phloem |
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2 club moss life cycle patterns |
Lycopodium - produces 1 type of sporangium, 1 type of spore, 1 gametophyte - gametophyte produces both antheridia and archaegonia * produces both sperm and egg Selaginella - produces 2 different sporangia, 2 different spores, 2 different gametophytes - large spores form female gametophytes with archaegonia * archaegonia produce eggs - small spores form male gametophytes with antheridia * antheridia produce sperm Flagellated sperm swims to egg to form zygote - zygote forms sporophyte |
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Ferns, equisetum |
Seedless vascular plants - dominant sporophyte, very small gametophyte - 12000 + living species: mostly ferns, many extinct species * calamites - horsetail |
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Ferns |
polypdium, true roots, stems and leaves (fronds) - sporophyte dominant - sporangia clustered into sorus on underside of frond * sporangia produce spores by meiosis - spores form tiny heart shped gametophytes that produce both sperm and egg - flagellated sperm fertilizes egg to form zygote * zygote forms dominant diploid sporophyte |
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Equisetum |
Horsetail (scouring rush); only living genus, all others extinct - equisetum has true roots, stems and microphylls * green stems are main photosynthetic organ * stems are jointed with microphylls or branches arising at each joint * stems are hollow for gas exchange * stems contain silica - strobilus at tip of stem produce 1 type of sporangium and 1 type of spore * spores from gametophytes that produce eggs and sperm |
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Rhizaria - group 2 |
Radiolarians, foraminiferans - characterized by slender pseudopodia for feeding and movement Radiolarians - common in fossil record back to precambrian; silica shells Foraminiferans - common in fossil record back to cambrian - calcium carbonate shells: deposits form White Cliffs of Dover |
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Alveolates - group 3 |
Dinoflagellates apicomplexans ciliates |
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Dinoflagellates |
ALVEOLATE Ceratium - component of marine and fresh water phytoplankton - brown photosynthetic pigments similar to diatoms and brown algae - 2 unequal flagella: rotate body * one in groove extending to posterior * other in groove around center of cell - some bioluminescent: produce bluish light at night * may startle predators or attract predators to eat dinoflagellate predators - some cause algal blooms: red tide * warm temperatures and excess nutrients cause blooms * produce neurotoxins that accumulate in fish and shellfish (harmful to fish and humans)
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Apicomplexa |
ALVEOLATE Intracellular parasites of animals Plasmodium - causes malaria; highest death rate of protists - female Anopheles mosquito vector, human only host - sporozoites form in salivary glands of mosquito * sporozoites infect humans during blood meal: form merzoites in liver * merozoites released from liver - infect red blood cells - merozoites formed and released from red blood cells in 48 or 72 hour cylces - merozoites form gametes and then sporozoites in ingested by second mosquito * completes plasmodium life cylce - malaria fatal without treatment; infects 40% of world pop in tropics * antimalaria medications; insecticides, bed nets, remove standing water |
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Ciliates |
ALVEOLATES Ciliated protozoans; Paramecium; Stentor; lost chloroplasts - ciliates characterized by macronuclei and micronuclei * macronuclei: functions for metabolism * micronuclei: function for sexual reproduction ( cells without micronuclei can only reproduce asexually) |
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Ciliates: Paramecium |
ALVEOLATE Specializations make paramecium appear multicellular - cilia: move food into mouth and move entire cell - oral groove: functions as mouth - food vacuoles: package food for digestion - anal pore: expels waste - contractile vacuole: expels excess water - conjugation: sexual reproduction in paramecium * 2 different mating types fuse and exchange micronuclei * new cells have 1 macronucleus and 1 micronucleus |
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Ciliates: Stentor |
ALVEOLATES Funnel shaped with cilia around anterior end |
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Stramenopiles - group 4 |
water molds diatoms brown algae |
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Watermolds |
STRAMENOPILE Resemble fungi due to convergence; many parasites - phytophthora: cause of Irish potato famin (1845) - saprolegnia: fish fungus |
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Diatoms |
STRAMENOPILE Unicellular; derived from red algae - brown photosynthetic pigments similar to dinoflagellates and brown algae - 2 piece, silica cell walls: fit like box and lid * diatom classification based on wall shape, ornamentation and symmetry (centric: radial & pinnate: bilateral) - mostly asexual reproduction * each new cell gets cytoplasm and 1 silica wall: regenerates other wall - shells accumulate in aquatic ecosystems: form diatomaceous earth deposits * used as detergents, polishes, filters, insulators, deodorizers - diatoms abundant in fossil record with many forms still living today |
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Brown Algae |
STRAMENOPILE Sargussum, Macrocystis (kelp); mostly marine - multicellular: largest and most complex algae group - derived from red algae - brownish photosynthetic pigments - characterized by thallus: plant like growth form * holdfast - anchors to substrate; not root * stipe - stem like structure that supports thallus * blade - leaf like structure that functions for photosynthesis * air bladders - floats that keep blades near surface - sexual reproduction: sargussum; sporic; heteromorphic * 2 multicellular stages in life cycle - look different * sporophyte (diploid) dominant, gametophyte ( haploid) reduced * multicellular diploid sporophyte forms sporangia (form haploid spores by meiosis) * haploid spores form multicellular haploid gametophytes (form gametes by mitosis) * flagellated sperm swim to egg * sperm fertilizes egg to form zygote * zygote forms new multicellular diploid sporophyte |
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Red algae - group 5 |
Polysiphonia, Porphyra ( nori) - most abundant algae in tropical oceans - re photosynthetic pigments |
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Porphyra |
RED ALGAE - 2 multicellular stages in life cycle; look different; opposite of brown algae - gameophyte (haploid) dominant, sporophyte (diploid) reduced - red algae used commercially * source of agar for growing microorganisms * provide moisture retainers for creams * source of carrageenan: suspending agent in chocolate milk and puddings * Porphyra gameophyte - nori - thin, sheet like growth form used as wrap for sushi |
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Green algae - group 6 |
Chlamydomonas, closterium, vovlvox, spirogyra, ulva, charophytes - major component of fresh water and marine phytoplankton |
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Chlamydomonas |
- unicellular, flagellated, haploid - cup shaped Chloroplast with eyespot for light detection - cellulose external wall: similar to higher plants - asexual reproduction: normal reproduction in chlamydomonas - reproduces sexually only in response to stress: scarce nutrients * zygotic life cycle - zygote only diploid phase |
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Closterium |
GREEN ALGAE - elongate - unicellular - central nucleus - 2 chloroplasts |
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Volvox |
GREEN ALGAE - colonial algae - rotating sphere of flagellated cells enclose new colonies |
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Spirogyra |
GREEN ALGAE - unbranched, multicellular filaments with spirally arranged chloroplasts - reproduce sexually by conjugation between different individuals |
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Ulva |
GREEN ALGAE - sea lettuce - 2 multicellular stages in life cycle - multicellular sporophyte and multicellular gametophyte look identical |
