Plant Diversity The Origin of Plants from Algae Plants evolved from algae. Oldest plant fossil is 475 millions years old! Plant- multicellular autotroph in which the embryo develops within the female parent. Multicellular? Autotroph? Embryo? Challenges of Life on Land 1) Obtaining resource Air Soil 2) Staying upright Lignin- hardens cell walls Challenges of Life on Land 3) Maintaining moisture Cuticle- helps the plant to maintain moisture Stomata- pores for gas exchange 4) Reproducing Plants must keep offspring from drying out Seeds in “jacket” Embryo develops in female Plant Diversity Charophytes- algae ancestors; lived in shallow water Bryophytes- no seeds (mosses) Pteridophytes- ligninhardened tissue (ferns) Gymnosperms- “naked” seeds (conifers) Angiosperms- seeds in ovaries (flowering plants) Video Angiosperms Reproductive structures are flowers Embryo develops within the female (in the flower) Flower Structure FLOWER- reproductive structure in angiosperms Stamen- Male part Anther- at tip; produces pollen (which contains sperm) Filament- stalk Carpel- Female part Ovary- Chamber that holds the embryo in the carpel (the “fruit”). Fruit or Vegetable? Fruit- ovary protecting SEEDS Vegetable- edible roots, stems, or leaves Computer Activity Phsuccessnet.com 19.1, 19.5 Turn in when completed in bin. Start homework. Transpiration Lab Transpiration- Loss of water from a plant, especially from the leaves. Transpiration Lab Photosynthesis: How a plant makes food; occurs in the chloroplast. Transpiration Lab Make a testable hypothesis to answer this question: “How is plant transpiration rate affected by light?” Transpiration Lab Data Table Transpiration Lab Variables Flower Dissection Reproductive structures male: stamen anther + filament female: carpels ovary + style + stigma Flower Dissection (carpel) Flower Function Reproduction (“pollination”) Insect-pollinators Wind-pollination Pollination Endosperm- nutrientstoring tissue; feeds the embryo as it develops Fruit- ripened ovary of a flower; protect & help disperse seeds Double fertilization 1) One sperm fertilizes egg cell zygote 2) Other sperm fertilizes outside of ovary forms ENDOSPERM: nutrients for embryo 3) Embryo + endosperm seed Seed dispersal Animal parts Hidden in fruits that are eaten or decomposed Water Wind www.phsuccessnet.com Seed development Root & shoot emerge cotyledons helps plant get nutrients dicot: two http://www.hobart.k12.in.us monocots: one Seed development http://images.encarta.msn.com/xrefmedia/aencmed/targets/illus/ilt/T630888A.gif Germination Absorbed water splits seed coat. Shoot makes its way to surface. Root grows down.