Plant Kingdom

Chapter Vocabulary Cuticle Stoma Xylem Phloem Guard Cell Non-Vascular Plant Root Stem Leaves Seeds

Characteristics of Plants All plants are Multi-celled All plants are Eukaryotes All plants use Various types of Chlorophyll for Photosynthesis All plants have cell walls made of Cellulose All plants store starch as a food reserve

Plants There are over 266,000 species of plants, most them are terrestrial but there are aquatic species. Plants are divided into two main groups a.Bryophytes- Nonvascular (16,000 species) b.Tracheophytes- Vascular (250,000 species)

Plants and the Adaptation to life on Land The three biggest obstacles to life on dry land were 1. Obtaining nutrients 2. Preventing water loss and 3. Reproduction

Obtaining Nutrients Algae are the immediate aquatic ancestors of plants and can get nutrients from the surrounding water. Land plants rely on soil for nutrients and water. Root systems had to be established to absorb nutrients and water. Important symbiotic relationships like those found in Mychorrhizae were developed.

Plant roots

Preventing Water Loss Land plants had to overcome the tendency to lose water to the air. (Dessication). Waxy coverings on the leaves prevented direct water loss (Cuticle) and tiny openings in leaves (called stoma) developed to regulated both the loss of water and the intake of CO 2.

Cuticle and Stoma

Reproduction Land Plants had to overcome the problem of reproducing on dry land where the lack of moisture prevented the sexual reproduction of egg and sperm. Non-motile Pollen replaced Sperm in advanced plants. Ovum were protected within specific plant structures like the Pistil and methods of pollinating plants became more diverse.

Other significant plant developments in evolution included…… Vascular Tissue- needed so that plants could increase in size. Seeds- needed so that the plant embryo is protected and has internal nutrients needed for growth. Flowers- needed so that reproductive structures could attract organisms to them for fertilization. Plant toxins- needed so plants could protect themselves. ( also thorns, spines and thick bark)

Plant Diversity All plants are divided into four major plant groups. This is based on vascular systems and reproductive methods a)Bryophytes- non vascular, no seeds b)Pterophytes- vascular and no seeds c)Gymnosperms- vascular and seeds form in cones d)Angiosperms- vascular and seeds develop from flowers and protected and distributed by fruit.

Mosses, Liverworts, Hornworts Bryophytes Non Vascular and Non-seed Small size due to water limitations Require water for sexual reproduction Reproduce by Alternation of Generation Large Gametophyte, Small Sporophyte

Ferns Members of the Plant Phylum Pterophyta Related to plant species Horsetail, and Whisk Ferns First plant species to have Xylem and Phloem Have a large Sporophyte and small Gametophtye generations. First plants with true roots, stems and leaves Reproduce by both spores and gametes Needs water for reproduction.

Fern Frond with Sori

Whisk Fern Horsetail Fern