Plants I Chapters 29

What you need to know! Why land plants are thought to have evolved from green algae. Why land plants are thought to have evolved from green algae. Some of the disadvantages and advantages of life on land. Some of the disadvantages and advantages of life on land. That plants have a unique life cycle termed alternation of generations with a gametophyte generation and a sporophyte generation. That plants have a unique life cycle termed alternation of generations with a gametophyte generation and a sporophyte generation. The role of antheridia and archegonia in gametophytes. The role of antheridia and archegonia in gametophytes. The major characteristics of bryophytes. The major characteristics of bryophytes. The major characteristics of seedless vascular plants. The major characteristics of seedless vascular plants.

Domain: Eukarya Kingdom: Plantae Bryophytes (non vascular): hornworts, liverworts, mosses Bryophytes (non vascular): hornworts, liverworts, mosses Tracheophyta (vascular): Tracheophyta (vascular): Seedless plants – horsetails and ferns Seedless plants – horsetails and ferns Seed plants Seed plants Class - Gymnosperms (naked seeds, flowerless): Ginko and Conifers Class - Gymnosperms (naked seeds, flowerless): Ginko and Conifers Class – Angiosperm (seeds, and flowers): monocots and dicots/eudicots Class – Angiosperm (seeds, and flowers): monocots and dicots/eudicots

Characteristics Multicellular Multicellular Eukaryotic Eukaryotic Photoautotrophic Photoautotrophic Cell walls made of cellulose Cell walls made of cellulose Peroxisomes to recover molecules from photorespiration Peroxisomes to recover molecules from photorespiration Stomata for gas exchange Stomata for gas exchange

Alternation of Generations Sporophytes (2n)  gametophytes (n)  back Sporophytes (2n)  gametophytes (n)  back Increasingly (evolution) dominated by sporophytes Increasingly (evolution) dominated by sporophytes Heterosporous: a few large, sessile, female spores and many small motile male spores Heterosporous: a few large, sessile, female spores and many small motile male spores

Bryophyta Phylums: liverworts, hornworts, and mosses Phylums: liverworts, hornworts, and mosses Terrestrial but close to water Terrestrial but close to water Seedless (spores) Seedless (spores) Non vascular Non vascular Small Small Rhizoids – root like anchorage system Rhizoids – root like anchorage system No flowers No flowers

Bryophyte Reproduction Dominant gametophytes Dominant gametophytes Sporophyte grows on top of fertilized female gametophyte Sporophyte grows on top of fertilized female gametophyte Heterosporous: Heterosporous: Male gametophyte – antheridium produces spermlike spores that swim (through water) to the egg Male gametophyte – antheridium produces spermlike spores that swim (through water) to the egg Female gametophyte – archegonium containing female spore (egg) Female gametophyte – archegonium containing female spore (egg)

Tracheophyta – Seedless Plants Horsetails and Ferns Horsetails and Ferns Vascular Plants – vessels transporting liquids Vascular Plants – vessels transporting liquids Xylem for H 2 O Xylem for H 2 O Phloem for sugar and nutrient transport Phloem for sugar and nutrient transport Lignified cells – lignin strenghtens cell walls Lignified cells – lignin strenghtens cell walls Sporophyte dominant life cycle Sporophyte dominant life cycle Roots for anchorage and absorption of water and other nutrients Roots for anchorage and absorption of water and other nutrients Heterosporous Heterosporous