Introduction to Plants

What is a Plant? Plants provide the base for the food chain Multicellular eukaryotes that have a cell wall made of cellulose Carry out photosynthesis (autotrophs) Can reproduce without water and can reproduce asexually or sexually Plants need: –Sunlight –Water –Minerals –Carbon dioxide –Movement of water and minerals through tissues

Overview of Plant Kingdom Four groups based on three features – water- conducting tissues, seeds, and flowers: Cone-bearing plants 760 species Ferns and their relatives 11,000 species Mosses and their relatives 15,600 species Flowering plants 235,000 species

Plant Cladogram Flowering plants Cone-bearing plants Ferns and their relatives Mosses and their relatives Green algae ancestor Flowers; Seeds Enclosed in Fruit Seeds Water-Conducting (Vascular) Tissue

Mosses & Their Relatives (Bryophytes) Non-vascular plants – they do not have tissues that are specialized to conduct water and nutrients, thus they stay small in size and must live in moist areas Depend heavily upon water to survive and reproduce Reproduce by spores, NOT seeds Groups of Bryophytes –M–Mosses –L–Liverworts –H–Hornworts

Mosses Grow in areas with water Adapted to nutrient-poor soil Tolerate low temperatures NO true leaves or stems Parts of plant only one cell thick Rhizoid Capsule Stalk Sporophyte Gametophyte Stemlike structure Leaflike structure

Examples of Mosses

Liverworts Look like flat “leaves” on ground Draw up moisture from surface of soil

Hornworts Reproductive structure looks different than liverworts

Human Uses of Mosses Sphagnum moss used as a sponge or for decoration Peat moss for gardening

Seedless Vascular Plants Contain vascular tissue that is specialized to conduct water and nutrients in the plant Reproduce by spores, NOT seeds Two types of vascular tissue: –Xylem – carries WATER up from roots –Phloem – carries NUTRIENTS up from roots

Ferns & Their Relatives Club moss, horsetails, and ferns Have true roots, leaves, and stems

Club Mosses Small plants that look like miniature pine trees MUCH taller (about 12 to 14 inches tall) than true mosses

Horsetails Grows one meter tall and looks similar to club mosses

Ferns More than 11,000 species Strong roots and large leaves called fronds Can survive in low light Typically have shiny leaves = covered with waxy cuticle = don’t dry out easily = can live in a drier environment than mosses

Examples of Ferns