Introduction to Plants –pp 551- 555 A. What is a plant?
1. Have cell walls of cellulose 2. Multi-cellular – made of many cells 3. Are eukaryotes and autotrophs. a. A few are parasites or saprobes 4. Develop from multi-cellular embryo 5. Carry out photosynthesis a. Using green chlorophyll pigments a & b with sun’s energy to produce food energy.
B. Life cycle
6. All plants have two generations for sexual reproduction a. Gametophyte generation produces gametes -haploid - ( 1N) b. Sporophyte generation produces spores diploid (2N) c. Seed plants need no water to move gametes from plant to plant d. Many can also produce asexually.
C. What plants need to survive
1. Sunlight a. b. 2. Water a. c. Energy of photosynthesis Often uses broad flat leaves to maximize absorption of sunlight One of raw materials of photosynthesis Need a constant supply of water.
3. Gas exchange with the atmosphere a. Needs oxygen for respiration . b. Needs carbon dioxide for photosynthesis 4. Movement of water and nutrients. a. Needs a system to carry water and nutrients to cells - Called a vascular system 5. Early Plants. a. Probably evolved from plants similar to green algae. .b. Algae also has cell walls and does photosynthesis. 6. Plant kingdom diversity a. 4 main groups of plants.-See chart page 555 in text b. Bryophytes - includes mosses and their relatives c. Ferns and their relatives d. Gymnosperms-cone bearing - conifers and others e. Angiosperms -flowering plants with seeds-most plants of this type 7. Groups based on 3 characteristics a. How they conduct water through tissues. b. Vascular or no vascular system c. Seed type or no seeds d. Flowers or no flowers
22-2 Bryophytes -pp. 556-559
1.Characteristics a. Lack vascular tissue to conduct water and nutrients throughout the plants. b. Moves water by osmosis short distances. c. No true roots, stems, leaves. d. Life cycle depends on water for reproduction 2. Groups a. Mosses -(Phylum Bryophyta) – pic page 556 can survive most any temp adapted to live in poor soil lives in wet habitats no true roots, but use rhizoids for anchoring and absorption. b. Liverworts(Phylum Hepaticohphyta) pic page 557 Can reproduce asexually by use of cup like structures called gemmae. c. Hornworts -(Phylum Anthocerohyta) pic p 557 3. Life cycle of bryophytes. a. Fertilization very dependent on water. Sperm swims to egg. b. Gametophtye generation -dominant and carries out the most photosynthesis. - spores germinates and produce a protonema - antheridia - produce egg gamete - archegonia - produces sperm gamete c. Sporophyte generation - grows out of body of gametophyte. d. Produces spores in a capsule at the end of a stalk. 4. Use of mosses a. Ability of sphagnum moss to absorb waster makes it useful for gardening. b. The low pH of peat moss also makes it a good gardening choice. c. Thick deposits of sphagnum moss call peat used for heating fuel in some countries.
22-3 Seedless Vascular Plants. pp 560-572
Vascular tissue – specialized for conducting water and nutrients throughout the plant. Tracheids - hollow cells connected end to end and form the xylem. Xylem - vascular tissue made of tracheids that carries water and nutrients Phloem - carries products of photosynthesis throughout plants. These types of vascular tissue can produce lignon which makes cells rigid and hold them upright. Xylem and phloem can both move water and nutrients against force of gravity.
1.Ferns and relatives characteristics seedless vascular plants. Most reproduce by spores- not seeds. Have true roots, stems and leaves. - Roots anchor and absorb water and nutrients. - Stems support plant, carry water and nutrients to other parts of plant, and spread out leaves. - Leaves – capture sunlight and carry out photosynthesis. Three example phylum Club moss - phylum - Lycophyta. o -mostly look by miniature pin trees. * Horsetails - phlyum Arthrophyta Leaves arranged in whorls that make it look like a horsetail. Colonist used them to scour pots and pans because leaves have crystals of silica (like sand). *Ferns – phylum Pterophyta. Often live in damp forests that have little light. Have roots called rhizomes that creep underground. Have large leaves called fronds. - Each indent in the fern is called a pinna. Life Cycle of Fern Sporophyte is dominant – usually what we see and call a fern. Sporangia form on underside of frond and are called sori. Sori release spores to grow gametophye generation to produce eggs and sperm Sperm fertilizes the egg which form a zygote which grows into the fem plant (sporophyte).
2-4 and 2-5 Seed Plants pp 564Can live anywhere because of special adaptations. Have flowers or cones for reproduction. These have the gametopyte generation. Allow seed to reproduce without water. Transfer of sperm by pollination as part of male gametophyte. - Pollen can be transferred to female gametophyte by wind, animals, insects, etc. Embryos protected in seed with seed coats. o Seed provides food for embryo to grow into the sporophyte. o Embyro is the zygote o Seed can survive many harsh conditions and then grow later .
Two types of seeded plants - Angiosperms and gymnosperms
Cone Bearers – Gymnosperms - Means naked seeds ( no seed coat.) Phylum Gnetophyta o About 70 species – lives in dry arid areas. o Cycads – phylum cycadophyta o Looks live a palm tree o Species live in tropical and subtropical areas. Ginkgoes – phylum Ginkophyta o Only one species.- needs a mild climate. o Can stand air pollution so is planted in city for a shade tree. o Source of Ginko biloba- thought to enhance memory –sold in o natural food stores. Conifers – phylum Coniferophyta o Most common – 500 species. o Includes pines, spruce, redwoods, sequoias, yew. o Conifers are a source of paper, lumber and etc o Most have needles that are modified leaves- helps prevent o water loss. o Most keep leaves year around, but some are deciduous i.e. o the loss their leaves each year. o Live in can live in sandy, rocky soil but also can live in o moist area such at the temperate rainforest.
. Seed bearers - Angiosperms – means enclosed seed. Most successful type of plant many species Most plant species are of flowering type. Most recently evolved. Flowering plants – phylum Anthophyta Main reproduction takes place in the reproductive organ called the flower. Flowers attract animals and insect to help pollinate aiding in producing seed. Flowers have ovaries which surround and protect the seed. Ovary develops into a fruit which protect seed and aids in its dispersal. Fruit has thick wall of tissue which animals eat and run through their digestive system and often carried long distances where it can sprout.
C22 Two classes Monocotyledons or monocots. See page 570 Single seed leave or cotyledon Parallel veins in leaves. Flower petals – 3 or groups of three. Vascular bundle in stem is scattered throughout Roots are mostly fibrous. Dicotyledons or dicots. Two seed leaves or dicotyledons. Branched veins in leaves Flower petal – multiples of 4 or five. Vascular bundle arrange in ring – usually at the out edge. Roots tend to be of the taproot style. Stem types can subdivide groups of flowering plants. Woody - thick walled cells make stems able to stand upright –ex. Trees and shrubs. Herbaceous - stem cells are smooth and nonwoody- ex. Petunias, grasses, dandelions, etc. Three types of life spans. Annual – lives only on year. Biennial – lives 2 years. Perennial – lives several years.