Kingdom PlantaeSlide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12How Did the Land Plants Arise?How Did the Land Plants Arise?Slide 15Slide 16Slide 17Major structural changes in sequenceSlide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42Slide 43Slide 44Major reproductive changesSlide 46Slide 47Figure 28.3Slide 49Slide 50Slide 51Reproduction summaryKingdom Plantae Evolutionary history.Modern definition of Plantshave embryos = a group of cells, starting to differentiate, but within a protective covering = spore, seed, ovary, uterus, etc.Old or other definitions;higher plants plus green algae – based on chlorophyl types plants plus all algae – all photosynthesize, are multicellularVolvox = green algae1. Evolution of structures: multicellularity and cell differentiationNeeded; • cells don’t separate.• connect at sides – form a hollow ball• some cells become gametes – move inside•These grow, outside dies, new groups released.Codium fragile, Japanese algae introduced to U.S.Looking at individual cellsHow do genes do this?1. Determine branch points2. Branch size?Problems of plants: having to do with being sessile.must protect selvesmust dispersemust meet matemust choose a good environmentmust deal with competition on sitemust live in the same place year round (seasons) must “eat” = CO² , water, lightIn water, algae – how are they done?? And is there a problem??How do algae cope??ProtectionDispersalMeet a mateChoose a good environmentCompetitionSeasons, etc.Food - must be within reach of sun.Regenerate quicklyMotile sperm, eggs, A timing issue – know how to tell time; will discuss later.Substrate? Random or focusedMay lead to moving to fresh water, even to land.Not much of a problem in the ocean. Red algae can live deeper – penetrance of wavelength.How Did the Land Plants Arise?Land plants are monophyletic, all descend from a single common ancestor.One synapomorphy: development from an embryo protected by tissues of the parent plant.Also called embryophytes.How Did the Land Plants Arise?Land plants retain derived features they share with green algae:•Chlorophyll a and b.•Starch as a storage product.•Cellulose in cell walls.Cellulose: a polysaccharide (multiple sugar units) with cross bridges.Starch is plant polysaccharideGlycogen is animal polysaccharide.Chitin is covering ofArthropods; *crabs, insectsSecondary wood GymnospermAngiospermsMajor structural advancesCuticleStomataXylem, phloemMajor structural changesin sequence•Cuticle•Tissue differentiation; root, leaf, stem.•Stomata•Conductive tissue•Secondary growthWhat do you need to live on land??Minimal requirement = cuticle – prevent dessication.Moss; add stomata.What is the reason for adding stomata? Needed for land and dry conditions; mosses and all higher plants.on underside of leaves or frondsOperated by h20 pressure – and sugar-starch amounts and sunlight.Value in letting in CO2, let out H20 for cooling. But retain most H20Moss- limited in height – no special support structures – these are club mosses – stand up betterTracheophytes: ferns and upAdd vascular tissue What is the reason for vascular tissue development??Today, tree ferns tropical. In ancient times – only trees.Xylem – has cellulose rings – like trachea of lungs; dead tissuePhloem – surrounding it – live tissueBoth for water and nutrient transport, xylem for supportWater transport up = cohesion model. Water evaporates at top, pulled into plant at bottom. An unbroken column of water in plant. Cohesion of water molecules pulls water upCohesion model for water transportMovement down in phloem – based on concentration of molecules (sucrose). Water moves to highest concentration area (osmosis) plus cytoplasm circulationTo get really tall, organize xylem – secondary growth.ZylemPhloemcambiumPhotosynthetic efficiency – large surface, organized internal structureMajor reproductive changes•Haploid dominant to diploid dominant•Development of spores (haploid)•Loss of aquatic sperm – replaced by pollen, which is airborne•Retention of egg on plant•Development of seed (food for embryo)•Development of flowers (pollen transport)•Many plants both male and female.Haploid dominant, motile sperm sporeDiploid dominantMotile spermDry sperm(pollen), seedsflowersWet environment.Ancestor = equal haploid and diploid plus isogamy = gametes identical in size.Figure 28.3Figure 28.3 figure 28-03.jpgMoss reproduction: heterogametic, motile sperm, egg retained. Diploid generation is “parasite” on dominant haploid generationFern; haploid generation reduced; diploid dominant– sperm still dependent on water.Pine: haploid reduced to pollen grain and egg (plus some support tissuePollen (sperm) is airborne.Addition of a seed. –food for embryoMale and female on same plant, but separate structuresGymnosperms = pine, etc.Flowering plants = angiospermsDevelop flowers = reproductive area; can be male and female or one or otherHaploid part = pollen (airborne) and egg, plus surrounding material.Seed. Flowers derived from specialized leaves.Can use insects, etc. to transfer pollenReproduction summary•Isogamy to heterogametic•Dominant haploid generation to dominant diploid•Go from aquatic sperm to aerial pollen•Switch from spore (haploid) to survive bad times to seed (diploid) with stored energy to survive bad