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How to remember taxnomy
- Keep = Kingdom
- Pond = Phylum
- Clean = Class
- Or = Order
- Froggy = Family
- Gets = Genus
- Sick = species
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Domain Archaea
cell walls-
structure-
environments
methanogens
- •cell cwalls lack peptidoglycan
- •plasma membranes have a unique lipid structure
- •live in extreme environments: Thermophiles (heat-loving) Halophiles
- (salt-loving)
- Methanogens- oxidize hydrogen gas with carbon dioxide and produce methane as waste product
- (swamp gas)
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Domain Bacteria
•Classification by Gram stain uses variation in cell wall composition
•Gram+ve (purple or blue)
outer peptidoglycan-rich wall traps violet dye
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Domain Bacteria•Classification by Gram stain uses variation in cell wall composition
- •Gram–ve (red)
- thinner layer of peptidoglycan under second plasma membrane (capsule) does not retain violet dye
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Spherical:
(sing.–us)
(paired)
(chains)
(bunch of grapes)
- –cocci (sing.–us)–
- diplococci(paired)–
- streptococci(chains)–
- staphylococci(bunch of grapes)
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Rod-shaped
- bacilli (sing. –us)
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Helical or spiral
(and corkscrew)
- spirilli (sing. –us)
- - spirochaete (corkscrew)
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Facultative anaerobe
- - uses oxygen if present
- -fermentation when
- oxygen is absent
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•Obligate anaerobe
- -lives in absence of oxygen
- -e.g. Rhizobium, a nitrogen-fixing bacterium
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relationships between organisms
Symbioses:
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symbioses (Symbiont) (Host) relations
- •Mutualism + +
- •Parasitism + -
- •Commensalism + 0
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Vectors
- are uneffected by a
- disease agent they carry to a host. (Commensalism)
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Cyanobacteria traits
- •most are photoautotrophs
- •unicellular, multicellular, colonial
- nitrogen fixation
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•plant symbionts convert
- N2 -> NH4+
- nitrogen ammonium ions
- (e.g.
- Rhizobium in legumes)
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•heterocysts –
specialized nitrogen-fixing bacterial cells
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Ecological roles of bacteria
- •Food chain
- •Digestion
- •Pathogens
- •Decomposers
- •Oxygen production
- •Nitrogen Fixation
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Get pictures of samples from lab
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Characteristics of Eukaryotes
- •Membrane-bound nucleus–DNA contained in linear chromosomes
- •Membrane-bound organelles
- •9+2 structure of flagella:
- •10-100 times larger than prokaryotes
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Plant vs Animal Eukaryotes
Plants have rectangluar fixed shape, chloroplast, cell wall and membrane (animal only has membrane)
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Protozoa:
- •heterotrophic
- –(animal-like)
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•Algae:
- autotrophic
- –(plant-like)
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•Absorptive:
–(fungus-like)
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Types of Protists
- •Protozoa: heterotrophic –(animal-like)
- •Algae: autotrophic –(plant-like)
- •Absorptive: –(fungus-like)
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Movement in Protists (most are aquatic or symbiotic with body tissues/fluids)
- •Flagella:–whip-like tail
- •Cilia:–tiny hair-like structures
- •Pseudopodia: –“false foot”
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Feeding Mechanisms in Protists
- •Phagocytosis: rhizopods (e.g. Amoeba), some ciliates (e.g. Didinium)
- •Filter feeding: some ciliates (e.g. Paramecium, Stentor)
- •Trapping: actinopods, formaniferans
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•Phagocytosis:
- pseudopodia extend around prey, create
- food vacuole; vacuole fuses with lysosome (digestive enzymes); waste released from food vacuole by exocytosis
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•Filter feeding:
- cilia sweep food particles into oral
- groove, food engulfed by phagocytosis
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•Trapping:
- Prey sticks to slender appendages, is
- engulfed by phagocytosis, and is drawn into the cell by cytoplasmic streaming
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Protists:
- Animal-like: Heterotrophs with no cell wall
- Fungi-like: Chemotrophs, some with chitin in cell walls
- Plant-like: Photoautotrophs, some with cellulose in
- cell walls
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Sexual Reproduction
- fusion of haploid gametes to form a diploid zygote
- gametes are usually from 2 different individuals (parents)
- unique gene combinations arise through sexual reproduction…
- different from conjugation in which genetic material is exchanged
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The
Movement from Water to Land
Problem #1:
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Solutions to problem 1
- •Rhizoids: roots that typically extend below ground
- (also source of dissolved minerals)
- •Apical Meristem: at root and shoot tips. Allows greater growth in both directions
- •Vascular System: Transports water/nutrients throughout
- plant.
- –Phloem:conducts sugars/organic compounds from leaves to rest of plant
- –Xylem:conducts water/minerals from roots to rest of plant, provides support
- (skeleton)
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•Vascular System: Transports water/nutrients throughout
plant.
made of
- –Phloem:
- conducts sugars/organic compounds from leaves to rest of plant
- –Xylem:
- conducts water/minerals from roots to rest of plant, provides support
- (skeleton)
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•Apical Meristem:
at root and shoot tips. Allows greater growth in both directions
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Rhizoids:
- roots that typically extend below ground
- (also source of dissolved minerals)
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The
Movement from Water to Land
Problem #2:
- Need to prevent
- excessive water loss
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Problem
#2: Need to prevent excessive water loss solutions
cuticle and stomata
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cuticle,Stomata
- •Waxy cuticle
- prevents evaporation (thickness depends on habitat)
- •Stomata: opening in leaf that regulates water
- loss
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The Movement from Water to Land
Problem #3:
: Need body support
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Solutions to problem 3, Need body support
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•Vascular tissue
- •Turgor Pressure: Central Vacuole (“pocket” of water)
- pushes against cellulose cell wall, gives cell shape
- –Wilting is caused by a lack of turgor pressure
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•Gametophyte: Haploid
generation
- –Produces
- haploid gametes by mitosis
- –Dominant
- generation for nonvascular plants
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•Sporophyte: Diploid generation
- –Produces
- spores by meiosis
- –Dominant
- generation for vascular plants
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Nonvascular
Plants
Mosses, liverworts, hornworts
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Nonvascular Plants habitats
•Confined to cool, damp environments
- –Rely on osmosis for distribution of water
- and nutrients (no vascular system!)
- –Gametes require water for movement
- •Flagellated sperm produced in antheridia,
- must swim
- •Eggs produced in archegonia
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Nonvascular Plants reproductive details
- •Gametophyte dominant
- •Sporophyte nutritionally dependent on gametophyte
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Seedless Vascular Plants:
- •Sporophyte-dominant, nutritionally independent of gametophyte
- •Water-necessary for sexual reproduction
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•Stele types:
how vascular bundles are arranged…
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•Stele
types:
how vascular bundles are arranged…
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Stele types:
•Protostele:
- •Protostele:
- phloem surrounding xylem core
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Stele types:
Siphonostele:
xylem and phloem surround pith
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Stele types:
•Eustele: discrete vascular bundles surround pith
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Seedless
Vascular Plant Phyla
- •whisk ferns
- •true ferns
- horsetails or “scouring rushes”
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Trends in Plant Evolution (3)
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•Greater efficiency of water transport
- •Reduction in size and dominance of
- gametophyte (relative to sporophyte)
- •Shift from Homospory to Heterospory
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Genius
specices
- Genius- caps
- specices-lowercase, usually afterwords
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