PowerLecture: Chapter 23 Plant Evolution

The Plant Kingdom Fig. 23-2, p.372

The Plant Kingdom

Fig. 23-3, p.372 Charophytes

The Plant Kingdom Non-VascularPlants(Bryophytes)

Nonvascular Plants (Bryophytes)  Gametophyte dominates life cycle  sperm require water to reach eggs  Three groups LiverwortsHornwortsMosses

Moss Life Cycle Zygote grows, develops into a sporophyte while still attached to gametophyte. Fertilization zygote sperm- producing structure egg- producing structure Diploid Stage Haploid Stage mature sporophyte Meiosis Spores germinate. male gametophyte female gametophyte

Fig. 23-8a, p.376

sporophyte gametophyte Fig. 23-9b, p.377 Peat Mosses

Fig. 23-9a, p.377 Peat Mosses

Fig a, p.377 Marchantia: A Liverwort

Female gametophyte Male gametophyte Fig b, p.377 Marchantia: A Liverwort

thallus (leaflike part) Fig c, p.377 close-up of gemmae Marchantia: A Liverwort

Vascular Plants  Internal tissues carry water and solutes

The Plant Kingdom Seedless Vascular Vascular Plants Plants

Fig. 23-4b, p.372 Seedless Vascular Plants

Fig. 23-4c, p.373 Seedless Vascular Plants

Fig a, p.378 sporangium Seedless Vascular Plants Seedless Vascular Plants

Fig b, p.378 strobilus Seedless Vascular Plants Seedless Vascular Plants

Fig c, p.378 Seedless Vascular Plants Seedless Vascular Plants

Fig d, p.378 Seedless Vascular Plants Seedless Vascular Plants

Fern Life Cycle Spores are released Sporophyte still attached to gametophyte zygote fertilization Diploid Stage Haploid Stage egg sperm mature gametophyte Spores develop meiosis Spore germinates rhizome sorus Fig p. 391

p.379

Fig a, p.380 A Carboniferous tree- sized club moss

stem of a giant lycophyte (Lepidodendron) seed fern (Medullosa), one of the early seed-bearing plants stem of giant horsetail (Calamites) Fig c, p.380Carboniferous

The Plant Kingdom Seed-bearing Vascular Vascular Plants Plants

Seed-Bearing Vascular Plants  Gymnosperms first  Angiosperms later

The Plant Kingdom Gymno-sperms

Angio-sperms

Gymno-sperms

Gymnosperms Gymnosperms  “naked seeds” (don’t form inside ovary)

Fig a, p.382 Conifer Characteristics

section through one ovule ovule surface view of one cone scale (houses two ovules) section through a pollen-producing sac surface view of one cone scale (houses a pollen-producing sac) meiosis fertilization seed coat embryo zygote mature sporophyte seeding pollen tube sperm- producing cell eggs female gametophyte pollination microspores form megaspores form seed Diploid Haploid Pine Life Cycle Fig , p. 396

Cycads  Palmlike  Pollen and seeds on different plants Strobilus of a “female” cycad

A Cycad

Fig b, p.382 A Cycad

Ginkgos  One surviving species, Ginkgo biloba  Deciduous trees w. separate sexes

Fig d, p.382Ginkgos

Fig e, p.382Ginkgos

Gnetophytes - Gnetophytes - Ephedra

Fig h, p.382 Welwitschia sp. - A Gnetophyte

The Plant Kingdom Angio-sperms

Angiosperms Angiosperms  Flowering  Double Fertilization (to be explained later)  Dominant land plants (260,000 species)  Ovules ( and later seeds) enclosed in ovary  Three main groups: magnoliids, monocots, and eudicots

Fig b, p.384 cycads ferns gymnosperms ginkgo other genera angiosperms (flowering plants) Time (millions of years) 0 Number of genera Angiosperms Angiosperms

Angiosperm Evolutionary Tree basal groups Amborella water lilies star anise magnoliids monocots eudicots Fig , p. 385

Fig. 23-5a, p.373 Gondwana 420 mya360 mya OrdovicanSilurianDevonianCarboniferous Bryophytes (liverworts) appear by 475 mya. Origin of earliest seedless vascular plants, in Silurian. Bryophytes diversify. Lycophytes, horsetails, ferns undergo early adaptive radiations. By 360 mya, seed plants evolve. Vast swamp forests; bryophytes, tree-size lycophytes, horsetails, ferns dominate. origin of conifers late in the Carboniferous. Plant Evolution

Fig. 23-5b, p mya65 mya Pangea PermianTriassicJurassicCretaceouspresent Origin of ginkgos, cycads. Conifers diversify. Extinction of most lucophytes and horsetails by end of Permian Ferns, cycads, conifers undergo adaptive radiations; by start of Cretaceous, conifers the dominant trees. Origin of flowering plants by the early Cretaceous. Rapid adaptive radiations and to dominance in nearly all habitats on land. Plant Evolution

sporophyte’s importance gametophyte’s importance green algaebryophytesfernsgymnospermsangiosperms zygote only, no sporophyte Fig. 23-6b, p.374

Evolutionary Tree for Plants green algae zygophytes, related groups charophytes bryophytes lycophyteshorsetails cycadsconifers flowering plants seed plants euphyllophytes vascular plants embryophytes (land plants) (closely related groups) ferns ginkgos gnetophytes Nested monophyletic groups Fig. 23-7, p. 387

p.375

Adaptations to Land  Roots  Shoots  Vascular tissues  Waxy cuticle