Plant Diversity Chapter 22.2-22.5
Chapter 22 Vocabulary • 22.2 • Bryophyte • Rhizoid • Gemma • Protonema • Antheridium • Archegonium • 22.3 • Vascular Tissue • Tracheid • Xylem • Phloem • Lignin • Root • Vein • Leaf • Stem • Rhizomes • Frond • Sporangium • Sorus
Chapter 22 Vocabulary • 22.4 • Gymnosperm • Cone • Pollen grain • Pollination • Seed • Embryo • Seed Coat • 22.5 • Angiosperm • Fruit • Monocot • Dicot • Cotyledon • Annual • Biennial • Perennial
Overview of the Plant Kingdom • Plants are divided into four groups based on these features: • Water-Conducting Tissues • Seeds • Flowers • Plants are also classified by other features, including reproductive structures and body plan.
Plant Evolution
Plant Classification • Seedless, Nonvascular Plants (Bryophytes) • Mosses and Liverworts • Seedless, Vascular Plants (Pteridophytes) • Ferns and Horsetails • Seeded, Vascular Plants • Gymnosperms (Cone-bearing) • Angiosperms (Flower-bearing) • Monocot • Dicot
Plant Life Cycle • Characterized by an “alternation of generations.” • During the two phases of the life cycle, mitosis and meiosis alternate to produce the two types of reproductive cells — gametes and spores. • The diploid (2N) phase is called the sporophyte, or spore-producing plant. • The haploid (N) phase is called the gametophyte, or gamete-producing plant.
Crash Course Biology • NonVascular Plant Reproduction
Bryophytes 22.2
22.2 Vocabulary • Bryophyte • Rhizoid • Gemma • Protonema • Antheridium • Archegonium
What is a Bryophyte? • Bryophytes are seedless, nonvascular plants. • These plants DO NOT have vascular or specialized tissues that conduct water and nutrients. • DO NOT have true leaves, stems, or roots. • The Bryophyte life cycle that depends on water for reproduction. • They take in water by osmosis. • They are low-growing plants found in moist, shaded areas.
Groups of Bryophytes • There are 3 groups of Bryophytes: • 1. Mosses • 2. Liverworts • 3. Hornworts
Groups of Bryophytes • 1) Moss • The most common types of bryophyte. • They are adapted to life in wet habitats and nutrient poor soil. • They can tolerate low temperatures. • They are basically clumps of gametophytes growing together.
Structure of a Moss Plant • Gametophyte – looks like mini evergreen (not true leaves) • Sporophyte – thin stalk with a capsule(not a true stem) • Rhizoids – anchor plant to the ground and absorb water and minerals from the soil
Human Uses of Mosses • Sphagnum mosses thrive in the acidic water of bogs. • Dried sphagnum can act as a natural sponge and can accumulate to form peat deposits. • Peat can then be cut from the ground and used as fuel.
Groups of Bryophytes • 2) Liverworts • Gametophyte looks like ‘leaves’ on the ground. • Sporophyte looks like a tiny umbrella. • These carry the structures that produce eggs and sperm.
Structure of a Liverwort • Some liverworts can also reproduce asexually by means of gemmae. • Gemmae are small multicellular reproductive structures. • In some species, gemmae form in gemma cups. • When washed out of the cup, the gemmae can divide by mitosis to produce a new individual.
Groups of Bryophytes • 3) Hornworts • Are found only in soil that is damp nearly year-round. • Gametophytes look like ‘leaves’ on ground. • Sporophyte looks like tiny green horns.
Life Cycle of Bryophytes • Bryophytes reproduce and develop by alternation of generations. • The gametophyte is the dominant stage of the life cycle and is the stage that carries out most of the plant's photosynthesis. • When a spore lands in a moist place, it germinates and grows into a mass of tangled green filaments called a protonema. • As the protonema grows, rhizoids grow into the ground and shoots grow into the air. • These shoots grow into green moss plants, which are the gametophyte stage of its life cycle.
Life Cycle of Bryophytes • Gametes form in structures at the tips of the gametophytes. • Sperm are produced in antheridia, the male reproductive structure. • Eggs are produced in archegonia, the female reproductive structure. • Some species produce both sperm and eggs on the same plant.
Life Cycle of Bryophytes
Seedless Vascular Plants Ferns & Their Relatives 22.3
22.3 Vocabulary • Vascular Tissue • Tracheid • Xylem • Phloem • Lignin • Root • Vein • Leaf • Stem • Rhizomes • Frond • Sporangium • Sorus
Evolution of Vascular Tissue • 420 million years ago, moss-like plants on land were joined by taller plants. • Evidence shows that these plants had vascular tissue, which is specialized to conduct water and nutrientsthroughout the plant.
What is Vascular Tissue? • Vascular tissue is specialized to conduct water and nutrients through the plant. • There are 2 types of vascular tissue: • 1. Xylem – carries water from the roots to the rest of the plant. • 2. Phloem – carries nutrients and carbs produced by photosynthesis to all parts of the plant.
Groups of Seedless Vascular Plants (Ferns & Their Relatives) • 1. Club Mosses • 2. Horsetails • 3. Ferns
Club Mosses • Commonly called ground pines • Bushy, tree like branches above, but unbranched at the base • Small leaves with single unbranched vein • Have deep growing roots like Rhizomes • Live in moist woods and clearings
Horsetails • Have underground Rhizomes • Reproduce by spores at the tips of branches • Found in wetlands
Ferns • Ferns have: • vascular tissues • strong roots • underground stems called rhizomes • leaves called fronds • Ferns all have roots, stems, and leaves. • Roots- absorb water and minerals • Leaves- carryout photosynthesis • Stems- support structures that carry water and nutrients.
Life Cycle of Ferns • Characterized by the dominant sporophyte stage. • Fern sporophytes develop haploid spores on the underside of their fronds in structures called sporangia. • Sporangia are grouped into clusters called sori.
Life Cycle of Ferns
Fern Life Cycle
Fern Gametophyte
