Plant Evolution & Diversity

Ancestors of plants were probably charophytes (green algae) Chlorophyll a and b, beta carotene Similar thylakoid arrangements Identical cell walls Starch as a storage carbohydrate Sperm and peroxisomes similar Charophytes Chara

Land provides new resources: CO 2 and light Plants Needed To Develop Roots Vascular tissue Lignin and sporopollenin Cuticle development Stomata devlopment

Land provides new resources: CO 2 and light Plants Needed To Develop Roots Vascular tissue Lignin and sporopollenin Cuticle development Stomata devleopment

Eukaryotic Multicellular Photosynthetic use chlorophyll a and b Cell walls made of cellulose Sessile Form an embryo enclosed in maternal tissue

Life cycle follows the Alternation of Generation Sporophyte generation: diploid, produces haploid spores by meiosis Gametophyte generation: haploid; produces haploid gametes by mitosis. The gametes eventually fuse to form a diploid zygote that grows into a sporophyte

Sporophyte generation has become more dominant Gametophyte has become microscopic Vascular systems have developed Seeds developed to protect the embryo Flowers and fruits are used as reproductive structures

Generation Trends

Plant Adaptations

Plants are divided by their adaptations to land living Divisions include Bryophytes Vascular Seedless Plants Gymnosperms Angiosperms

Lack true roots, stems & leaves Have rhizoids Considered non-vascular Rely on diffusion Asexual reproduction predominates Fragmentation Sexual reproduction uses archegonia & antheridia Gametophyte is the dominant form (haploid) Sporophyte grows out of the gametophyte after sperm & egg unite Sporophytes produce spores via meiosis within a sporangium called a capsule 3 major groups: Mosses, Liverworts & Hornworts

Antheridia Archegonia

Bryophyta Mosses Moss Carpet

Bryophyta Mosses Moss Stages

Bryophyta Mosses Life Cycle

Bryophyta Mosses Gemmae Cups Moss Capsule

Hepaticophyta - Liverworts

Hepaticophyta Liverworts Life Cycle

Antheocerophyta - Hornworts

Horsetails, Club Mosses & Whisk Ferns Vascular tissue Cuticle Rely on watery environments for reproduction

Ferns Division Pteridophyta Sporophyte Generation (fronds) Produces haploid spores via meiosis in a sporangium called a sorus (sori) Some are heterosporus Microspores give rise to male gametophytes Megaspores give rise to female gametophytes Gametophyte Generation (Prothallus) No vascular tissue in the prothallus Archegonia & antheridia can be found on the same gametophyte

Ferns Division Pteridophyta

Cycads, Ginkgo & Conifers Naked Seed Vascular tissue, pollen and seeds (by fertilization) Needle like leaves Reproductive cones Gametophyte Generation Male gametophyte is pollen Female gametophyte is reduced too Sporophyte Generation Embryo is protected by a seed coat Embryo stays dormant until germination

Naked Seed

Coniferophyta - Conifers Naked Seed Vascular tissue, pollen and seeds Gametophyte Generation Male gametophyte is winged pollen, contains the tube cell Female gametophyte is found in female cones The embryo and seed develop together Sporophyte Generation (diploid) Produce cones, male and female Spores give rise to the gametophyte within the sporophyte

Coniferophyta - Conifers Naked Seed

Coniferophyta Conifers Life Cycle Naked Seed

Have covered seeds Vascular plants more efficient xylem Broader leaves Two major groups: Monocots & Dicots Produce flowers Contain the anther and carpel More efficient for pollen dispersal Ovary develops into a fruit with seeds inside