Download Plant Kingdom Notes

I.
II.
Plantae (Plant) Kingdom
General—over 400,000 species—10 phyla of extant plants (have surviving and extinct members)
--argument over whether some or all green algae should be included in kingdom-A. features
1. eukaryotic
2. multicellular (usually)
3. autotrophic—photosynthesis
B. major trends (evolution)
1. evolved from green algae approx 500 million years ago. Evidence:
a. similar (homologous) chloroplasts
b. walls with cellulose
c. peroxisomes
d. sperm structure
2. adaptations needed to become terrestrial
a. control water loss
(1) cuticle on epidermis
(2) stomata
b. transport water & food (xylem & phloem)
c. resistant spores—survival in adverse conditions
d. protective packaging for gametes & embryos—depending on plant, include:
(1) multicellular gametangia (gamete producing structures)
(2) pollen grains—contain male gametophytes
(3) seeds
(4) fruits—help disperse seeds
3. alternation of generations— in all land plants
--2n diploid spore-producing stage alternating with n, haploid gamete-producing stage—
a. gametophyte stage
(1) plant cells haploid
(2) gametes produced
b. sporophyte stage
(1) during fertilization, egg & sperm fuse to form diploid zygote—the sporophyte
(2) sporophyte divides by mitosis
(3) spore produced
c. primitive plants—gametophyte prominent
d. complex plants—sporophyte prominent
Overview of terrestrial plants
A. Nonvascular Plants (informally called Bryophytes)
1. do not have an extensive transport system
a. lack vascular tissue
b. lack true roots
c. gametophyte phase prominent
2. Three phyla:
a. phylum Hepatophyta (liverworts)
b. phylum Anthocerophyta (hornworts)
c. phylum Bryophyta (mosses)
B. Vascular Plants (trachephytes)
--vascular tissue: a transport system composed of cells joined into tubes—
--2 groups
1. Seedless Vascular Plants (lower vascular plants)
a. phylum Lycophyta (club mosses, spike mosses, and quillworts)
b. phylum Pterophyta (ferns, horsetails and whisk ferns)
2. Seed plants—2 groups
a. gymnosperms—“naked seed”—seeds not enclosed
(1) phylum Cycadophyta—cycads
(2) phylum Ginkophyta—ginko
(3) phylum Gnetophyta—gnetophytes (Gnetum, Ephedra and Welwitschia)
(4) phylum Coniferophyta—conifers most familiar
-- example: pine trees—have both pollen cones & ovulate cones
b. angiosperms—flowering plants (most successful)
(1) seeds develop inside chambers called ovaries in a flower
(2) phylum Anthophyta—2 classes of flowering plants; used to be divided into monocots
and dicots based on numbers of cotyledons (seed leaves) in embryo. New evidence for
(a) monocots—same as before—(more than ¼ of angiosperm species)
(b) eudicots—“true dicots”—(more than 2/3 of angiosperm species)
(c) rest divided into several small lineages