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59 Cards in this Set
- Front
- Back
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When did plants first appear on terrestrial land? |
In the early Devonian scene land plants developed their body plans after they colonised terrestrial environments, the complete opposite to animals |
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Angiosperms |
Flowering plants, most diverse (240,000 species) |
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Bryrophytes |
-most primitive land plants, non vascular -liverworts, hornworts and mosses |
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Lycopods |
Ferns and fern allies, vascular plants that reproduce by spores |
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Coleoochaete life cycle |
gametophytes produce haploid sperm and eggs which form a zygote, meiosis occurs to create spores that grow into gametophyes |
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Land plants life cycle |
Similar to Coleoochaet, except after zygote a sporophyte is produced (2n) an alternation of generations that creates spores to then create gametophytes |
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Monophyletic |
descended from 1 common ancestor |
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paraphyletic |
a group is paraphyletic if it consists of the group's last common ancestor and all descendants of that ancestor excluding a few—typically only one or two—monophyletic subgroups. e.g. reptiles |
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Gymnosperms |
seed producing plants e.g. cycads, ginko, conifers, gnetales |
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Liverworts (3 main groups) |
-Marchantiales (thalus) -Metzgeriales -Jungermanniales (leafy) |
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Characteristics of Liverworts |
-oil bodies -elaters (used in plant spores) -luvluaric acid -non vascular (not efficient, cant transfer h20 around body so plant must be small and flat) |
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Artheridia |
-male sex organ that contains sperm cells |
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Arthergonia |
-female sex organ that contains egg cells |
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Sporophytes in Liverworts |
-black capsule is the sporangium -parasitic on the female gametophytes, contains no photosynthetic material. -white stalk elongates rapidly (seta), capsule releases spores |
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Capsule Dehiscence |
-as capsule dries out, spores spread out -spores are spread out and released to grow into gametophytes -as cells dry out, elaters on sporangium curl up and the stress make the sporangia break |
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Marchantiales |
-most common liverwort -scale like cells -each cell has air pores ( that act similarly to stomata, though always open) -rhizoids grow into substrate, anchor plant in lower epidermis |
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Marchantia |
Marchantia is a genus in the family Marchantiaceae of the order Marchantiales, a group of liverworts -contains gemma cup: asexual reproduction, the flattened plant body is a haploud gametophyte with gemma cups that contain gemmae -ventral scales -peg rhizoids -artheridia are contained in umbrella shaped artheridiaspores |
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Riccia |
In the order Marchantiales, these liverworts colonise bare ground, efficient after fires -arthegonia embedded in thalus, sporophyte grows enclosed in the gametophyte |
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Hornworts -gametophyte |
e.g. Anthoceros -bluey green (bacteria grows in thallus, symbiotically fixes N) -dichotomous leave pairing -has ventral pores (dont open and close but look like stomata, function is to allow bacteria to enter and grow) |
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Hornworts -sporophyte |
-horn like -one whole elongated sporangium, no capsule or stalk -green (photosynthetic but still dependent on gametophyte to grow but not survive) -stomata only occurs here -sporophyte has elatin, thickened cell walls |
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Mosses |
-typically grow as epiphytes in wet tropic environments -can grow in diverse enviro -colonise bare ground (after fire) -dont usually grow by itself |
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Mosses -gametophyte |
-most dominant form -leafy -mid vein (not all mosses have a mid vein but no liverworts have midveins -red rhizoids are branched and multicellular (liverworts rhizoids are unicellular and non branched) |
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Mosses -sporophytes |
-grow from where archegonia is fertilised -spores germinate over wet ground into protonema which cover the ground -capsule is green -at base of "leaves", there is a group of large distinctively coloured Alar cells Alar cells- important in re orientating leaves when they dry out or turgid |
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Mosses -sporophytes |
-old archegonia gets carried up to the tip of the sporophyte to form a calyptra that protects the capsule containing the embryonic sporophyte -once the cap falls off, peristone teeth is revealed -antheridia has tightly packed hairs to trap water and keep hyrdated, also embed into the neck of the archegonia to fertilise egg cell -not a part of gametophyte from beginning |
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Persitone Teeth in mosses |
-differentially thickened on the outside -as cells dry out the thickenings want to push the teeth out and operculum (lid to capsule) to release spore. when wet, the teeth will close |
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Andreaea (Moss) |
-no seta (stalk is evolved among mosses) -primitive sporophyte, no elaters or teeth -capsule splits into four parts |
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Sphagnum (Moss) |
-located in swampy alpine areas e.g. holds the water melted from ice -bright green, exchanges ions Sporophytes -black capsules, contains operculum but no peristome -no stalk, has bulbous foot -major component of horticultural potting mix -prone to damage and slow to recover -leaves consist of living photosynthetic cells and large empty hyaline cells that act as sponges |
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Lycopods |
-extensive fossil records -oldest living vascular plants -stems with "leaves" (microphylls) -contain sporangia, base of leaves on stem -in fertile regions, leaves are cone like |
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Enation Theory |
The evolution of microphyllous leaves -small outgrowths, or enations, developed from the side of early stems, became photosynthetic and then gained vascular tissue |
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Phylloglossum Drummondi (lycopod) |
-v small, few leaves, underground bulbous -found in coastal areas like anglesea -cone like capsule -like a juvenile lycopodium |
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Lycopodium |
gametophyte is photosynthetic contains all its reproductive parts at a young age petamorphosis: going into reproductive phase at a young age |
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Selaginella (Lycophyte) |
-v small, fern like -heterosporous alteration of generations -sporophytes produce microspores that produce microgametophytes (sperm) and mega spores that produce megagametophyte (egg) to combine and produce a zygote -base of leaf contains a ligule |
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Arborescent (tree-like) Lycophytes |
-early devonian era, large tress in swampy forests -grew by dichotomous branching -determinant growth -no root system, two shoot systems, above and undergound -extra vascular capacity because so large |
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Psilophytes |
-small vascular plants with no roots -creeping underground stem + aerial stem -green stems branch dichotomous that contain enations -common in tropical areas (pot plant weed) -tracheids born first in bundles and mature to produce the stele (central core of the stem) -first xylem to develop is protoxylem |
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Psilophyte -Psilotum |
-no roots, have creeping underground stem -stems contain 3 sporangia fused together -where ever there is a sporangia, the enation is bifid (forked) -homosporous |
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Psilotum |
Gametophyte -simple but multi-cellular, sub-terranian and non-photosynthetic -symbiotic relationship with root fungus -contains rhizoids, sex cells on outside young sporophyte has same appearance as gametophytes |
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Rhyniophytes |
-early vascular extinct devonian plants - sporophytes consisted of branched stems bearing sporangia -dichotomously branched stem -no "leaves" or roots |
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Trimerophyte |
-ancestral group from which both the ferns and seed plants evolved. -dichotomously branching -overlapped dichotomy |
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Equisetum |
-no major role in vegetation -none in Aus, only genus in Nth America -small herbaceous plants -homosporous -colonises baregound with creeping rhizoids (weed) -epidermis with silica crystals (anti-herbivory, gritty to eat) -"horse tail" "scouring brush" -spores have two part outer wall, differentially thickened cell walls, elaters spring out when dry |
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Equisetum -gametophyte |
-hardly any morphology -small thallus -produce antheridia and archegonia -sporophytes dont grow attached to gametophyte -apical meristem is one cell |
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Seed Plants |
-contain secondary growth seeds -woody trunks, vascular cambium, allowed for the evo of trees -integuments (seed coat) -heterosporous alternation of generations -megaspore retention, continue to be reabsorbed -megasporangium wall=nucellus -ovule=a megasporangium with an integument |
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Conifers -sexual reproduction |
megasporangium (the ovule) undergoes meiosis> 4 egg cells
-ovule releases sticky droplet, pollen sticks to it and the integument grows over the top of it and traps it in the ovule -no requirement for free water -remaining gametophyte used as food source ovule (pre fertilisation) seed (post fert) -integument is called the testa in the seed |
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Elkinsia |
-old seed plant fossil -dichotomous branched (primtive) -ovules in clusters at tip |
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Telome Theory |
-evolution of the integument -evolved from dichotomous branched plants, these braches sterilised and aggregated to from the integument |
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Apical Meristem |
the first cell at the tip of the shoot and the root and is a region of actively dividing cells. Tunica-adds width to meristem (outermost layer of cells) Corpus-body of meristem, will become primary tissyes |
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Vascular Cambium |
-source of secondary xylem and phloem growth, located between xylem and pholem in the stem and root -what adds to the trunk of a tree |
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Ferns |
-"leaves" are called fronds, which are split down into leaflets called pinnae -some aquatic, mostly terrestrial, some epiphytes -can grow in cold areas -creeping stem: rhizome -leaf stalk:lipe |
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Ferns |
-fern rhizomes don't have secondary thin, so thin -distinctive feature: grow from a single permanent apical cell |
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Trichomanes |
-kidney shaped leaf, doesnt look like a fern but -dichotomous and white dots that contain sporangium under the fertile fronds -leaves circinate vernation: As the fern frond is formed, it is tightly curled so that the tender growing tip of the frond is protected within a coil. |
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Leptosporangium Eurosporangium |
-a sporangium formed from a single epidermal cell; characteristic of modern ferns, single cell, thin, stalk with sporangia on top -sporangium developed from more than one intial cell e.g. marrattia (massive thick walls, numerous spores, common to land plants) |
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Fern Gametophytes |
-small heart shaped -green, free living, short lived archegonial neck grow near apical meristem -antheridia live in the middle |
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Vegetative Propagules |
-apical meristems that have developed from surface cells, will drop off when frond touches ground and releases roots to form new genetically identical plant |
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Annulus |
a single row of specialized cells on the outer rim of a fern sporangium that serves in spore dispersal. |
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Sporangium Development |
Annulus Position Primitive>>>>>>>>>>>>>>>>Advanced minimal (archegonial neck)>terminal>lateral>vertical |
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Gleichenia |
-found in wetter areas, growth of leaves are indeterminate -divaricate leaf -large sporangia, 3 clustered together -annulus is lateral (advanced) |
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Ophioglossum |
1-2 small leaves -elongated stalk contains large sporangia -eurosporangiate gametophyte -small, sub-terranean, non synthetic, symbiotic |
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Water Ferns SAM |
Salvinia -chronic tropical weed that has been effectively controlled by weevils -free floating, from Sth America -reproduces colonially -submerged leaves that look like roots, leaves float up because of hairs (dont sink) |
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Water Ferns SAM |
Azolla -free floating, common in aus dams & still water -gives water red appearance -small simple fronds -leptosporangiate (narrow stalk) -sporangia formed in sac like structure-sporocarp -massulae: a hardened layer of cytoplasm formed around the maturing microspore in some heterosporous ferns to hook onto megaspores |
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Water Ferns SAM |
Marsilea -staple food of aborigines -free floating -has a rhizome with leaves (like pink four leave clover) -leaves float on surface (circinate vernation) -heterosporous plants in sporocarps on stalks -spores lie in soil waiting to be rehydrated to form gametophytes |
