Ch 22- Plant Diversity

• What is a plant?– Multicellular eukaryotes, have cell walls made of cellulose– Carry out photosynthesis using pigments-chlorophyll a and b

• Welcome to Discovery Education Player• Plant Life Cycle

– Sporophyte- diploid phase produces spores– Gametophyte- haploid phase produces gametes

• What do plants need to survive?– Sunlight, water and minerals, gas exchange, and transport of

water and nutrients

• First plants evolved from organism similar to modern multicellular green algae

• 4 groups in plant kingdom based on water-conducting tissues, seeds and flowers– Mosses and their relatives– Ferns and their relatives– Cone-bearing plants– Flowering plants

Sec 2- Bryophytes

• Bryophytes- nonvascular plant– Depend on water for reproduction– Mosses

• What adaptations of bryophytes enable them to live on land?– Can draw up water by osmosis a few cm above

ground• Three main groups of bryophytes– Mosses, liverworts, and hornworts

• 3 phyla of non-vascular called Bryophytes– Mosses belong to Phylum Bryophyta– Others include liverworts and hornworts

• Characteristics include– Usually grow on land near streams and rivers– Most primitive type of plant and abundant in polar regions– Closely related to algae and most terrestrial– Need water to reproduce sexually– Contain rhizoids-false roots-root like structure that

anchors moss and absorbs nutrients• Life cycle of bryophytes

– Gametophyte is dominant stage– Antheridia- male reproductive structure– Archegonia- female reproductive structure

Sec 3- Seedless Vascular Plants• Vascular tissue- type of tissue that transports water and dissolved

substances from roots to leaves– Types include xylem and phloem

• Xylem transports water made up of tracheids- hollow cells with thick cell walls that resist pressure

• Phloem transports organic compounds• Can move fluids against gravity

• Seedless vascular plants- club mosses, horsetails, and ferns– Ferns have underground stems called rhizomes and fronds which are large leaves

• What are the characteristics of three phyla of seedless vascular plants?– Roots, leaves, veins, stems– Roots- underground organs that absorb water and minerals– Leaves- photosynthetic organs, contain one or more bundles of vascular tissue– Veins- vascular tissue in leaves made of xylem and phloem– Stems- supporting structures, connect roots and leaves, carry water and

nutrients

Life Cycle of Ferns

• Diploid sporophyte is dominant stage in ferns and other vascular plants

• Sporangia- structure in ferns that contains spores, diploid

• Sori- cluster of sporangia on underside of a fern frond

Sec 4- Seed Plants

• Gymnosperms- seed plants that bear seeds directly on surface of cones– Gymnosperm means “naked seed”– Conifers such as pines and spruces, cycads, ancient ginkgoes

• Angiosperms- flowering plants that bear their seeds within layer of tissue that protects seed

• What adaptations allow seed plants to reproduce without standing water?– Flowers or cones- allow transfer of sperm by pollination and

protection of embryos in seeds

• Cones- seed bearing structure• Flowers- seed bearing structure of angiosperm• Pollen grain- male gametophyte in seed plants• Pollination- transfer of pollen from male reproductive structure to

female reproductive structure• Seed- embryo of living plant that is encased in protective covering• Embryo- organism in its early stage of development• Seed coat- structure that surrounds and protects a plant embryo

and keeps it from drying out• What are the four groups of gymnosperms?

– Gnetophytes, cycads, ginkgoes, and conifers– All reproduce with seeds

• Conifers- most common– Includes pines, cedars, spruces, redwoods, sequoias, junipers

Sec 5- Angiosperms

• Angiosperms- members of phylum Anthophyta, originated on land

• What are the characteristics of angiosperms?– Flowers- reproductive organs– Flowers contain ovaries- surround and protect the

seeds– Fruit- wall of tissue surrounding the seed

Diversity of Angiosperms

• What are monocots and dicots?– Named for # of seed leaves, or cotyledon- first leaf or first

pair of leaves produced by embryo of seed plant• Monocots- single cotyledon, parallel veins, flowers in

multiples of 3’s, vascular bundles scattered throughout stem, fibrous roots– Corn, wheat, lilies

• Dicots- two cotyledon, branched veins, flowers in multiples of 4 or 5, vascular bundles in ring, taproot– Roses, tomatoes, oaks

• Woody plants- thick cell walls– Trees, shrubs, vines

• Herbaceous- smooth and nonwoody stems– Dandelions, sunflowers

• What are the three categories of plant life spans?– Annuals- flowering plants that complete a life cycle within

one growing season• Wheat

– Biennials- flowering plants that complete life cycle in 2 yrs• Celery

– Perennials- flowering plants that live for more than 2 yrs• Asparagus, palm and maple trees