Presentation on theme: "Chapter 16 - Plants, Fungi, and the Move onto Land"— Presentation transcript:
1Chapter 16 - Plants, Fungi, and the Move onto Land Terrestrial Adaptations - living on land poses different problems from living in waterPlants require structural specializationsRoots and shootsShootsLeaves – photosynthesis and gas exchangeStems – transport water up and sap downRoots – absorb water and dissolved minerals..
2Leaves are main photosynthetic organs Gametangia protect gametes from dehydration; female gametangia protect developing embryosCuticle reduces water lossStomata allow gas exchange between plant and atmosphereLignin hardens cell wallsShoot supports plant; may perform photosynthesisVascular tissues transport water, minerals, and sugars; provide supportRoots anchor plant; mycorrhizae (root/fungus associations) help absorb water and minerals from the soil)Whole alga performs Photosynthesis; absorbs water, CO2, and minerals from the waterAlgaSurrounding water supports the alga
3True root, stems, and leaves have vascular tissue that form “veins” in the tissues. Xylem – transports water and minerals through dead cells that form “straws” in the tissuePhloem – living cells that transport sap (sugars in water) throughout the plant..
4Plant Diversity Angio-sperms Gymnosperms (e.g., conifers) CenozoicMesozoicPaleozoicCharophyceans (a group of green algae)Bryophytes (e.g., mosses)Seedless vascular plants (e.g., ferns)Gymnosperms (e.g., conifers)Angio-spermsOrigin of plantsEarly vascular plantsFirst seed plantsDiversification of flowering plants
5Nonvascular Plants – Bryophytes No vascular tissue, must be low to ground, live in moist areas, no true roots, stems, or leavesMosses – the most familiar..
6Plants, including mosses, have two distinct versions of the plant The gametophyte, which produces gametesThe sporophyte, which produces spores(phyte = plant)..
7Gametes (sperm and eggs) The life cycle of a moss exhibits an alternation of generationsSporesnMitosisSporophyte2nGametes (sperm and eggs)FertilizationZygoteSpore capsuleMeiosisGametophyteHaploidDiploid
8Seedless Vascular Plants - Ferns Have vascular tissue; true roots, stems, and leaves; do not produce seeds; have flagellated sperm that swim to ovule
9Seed Plants – Gymnosperms & Angiosperms Seed – embryonic plant with food supply packaged in a protective coat..
10Gymnosperms - Conifers Most all are evergreens; produce seed cones and pollen cones; sporophyte generation is more prominent than the gametophyte generation..
11Pollen grain Ovule Is actually the much-reduced male gametophyte Fertilizes the female gametophyteOvuleContain the female gametophyteWill develop into the seed..
12AngiospermsSupply nearly all our food and much of our fiber for textilesMore efficient water transport and the evolution of the flower help account for the success of the angiosperms
13A characteristic of angiosperms is double fertilization One sperm nucleus fertilizes and egg in the female gametophyte = zygoteOne sperm nucleus fertilizes another cell in the female gametophyte (not the egg) = endospermThis synchronizes the development of the embryo and the food reserves. The entire ovule develops in to a seed.IntegumentsSpore(a) OvuleHaploid (n)Diploid (2n)Pollen tubePollen grain(male gametophyte)Female gametophyteEgg nucleusDischarged sperm nucleus(b) Fertilized ovuleSeed coat (derived from integuments)Food supply (derived from female gametophyte tissue)Spore caseEmbryo(new sporophyte)(c) Seed..
14Life cycle of Angiosperms Mature sporophyte plant with flowersGerminated pollen grain (male gametophyte) on stigma of carpelAnther at tip of stamenPollen tube growing down style of carpelOvary (base of carpel)Embryo sac (female gametophyte)EggSperm nucleiFertilizationEndospermZygoteEmbryo (sporophyte)Fruit (develops from ovary)Seed (develops from ovule)SeedGerminating seedSporophyte seedlingHaploid (n)Diploid (2n)..OvuleLife cycle of Angiosperms
15The dominant stage of the angiosperms is a sporophyte with gametophytes in its flowers StamenAntherFilamentOvulePetalPistilStigmaStyleOvarySepalContains female gametophyte..Contains male gametophyte = pollen
16Fruit = ripened ovary usually containing seeds.. FlowerSepals = outer whorl of modified leaves; protectionPetals = second whorl of modified leaves; bright, showy; attract pollinatorsStamen = anther & filament; produces pollen – the male gametophytePistil = stigma, style, & ovary with ovules; ovules contain the female gametophyteFruit = ripened ovary usually containing seeds..