Presentation on theme: "2001: A Plants without Seeds Odyssey Michael Patterson, Rebecca Flanagan, and Kellie O’Hearn."— Presentation transcript:
2001: A Plants without Seeds Odyssey Michael Patterson, Rebecca Flanagan, and Kellie O’Hearn
1.Evidence of Early Plant Evolution 2.Monophyletic, Clade, and Synapomorphies 3.Evolved Nonvascular Features 4.Plant Life Cycle 5.Moss Life Cycle 6.Vascular Plants 7.Evolved Vascular Features 8.Vascular Plants 9.Nonvascular Analogous Structures 10.Homospory and Heterspory 11.Nonvascular Plant Clades 12.Vascular Plant Clades 13.Water 14.Evolution of Plants Scene Selection
1870 Dawson discovered Psilophyton, means “naked plant” Kidston and Lang discovered similar “naked plant” fossils, named genus Rhynia 1915 Reconstruction of extinct Psilophyton Reconstruction of Devonian period Rhynie chert Evidence of Early Plant Evolution
A monophyletic clade shares synapomorphies. Ten groups: 7 vascular and 3 nonvascular Synapomorphy of vascular clade: tracheids Nonvascular: No clade
Evolved Nonvascular Features Evolutionary adaptations have granted nonvascular plants global, widespread existence. Waxy Cuticle & Water Open Stomata Gametophytes/Gametangia of the liverwort Marchantia
Plant Life Cycle Mitosis vs. Meiosis: Mitosis – formation of gametophytes, sporophytes, and gametes Meiosis – formation of spores Gametophyte vs. Sporophyte Gametophyte – most prominent stage in nonvascular plants Sporophyte – most prominent stage in vascular plants Haploid vs. Diploid: Haploid – one copy of chromosomes Diploid – two copies of chromosomes
Antheridium – M Archegonium – F Rhizoid, Protonema, Bud? Specific to Mosses Protected Embryo Gametophyte vs. Sporophyte Gametophyte – most prominent stage in nonvascular plants Sporophyte – most prominent stage in vascular plants
Vascular Plants Synapomorphy of vascular clade: tracheids Tracheid – a type of cell that is the preeminent carrier of water of the xylem PhloemXylem “Pathway for Transport” “Rigid Structural Support”
Evolved Vascular Features “Branching, Independent Sporophyte” A vascular lycophyte sporophyte Rhizoids and Rhizomes Evolution Roots Microphyll (Simple Leaf)
Nonvascular Analogous Structures VascularNonvascular Stems, xylem and phloem Small growth pattern, capillary action and diffusion Roots and leaves, acquisition of nutrients and products of photosynthesis Symbiotic relationship with fungi, facilitating absorption of water and nutrients
Nonvascular Plant Clades Left: Leafy Gametophyte Right: Thalloid Gametophyte Short sporophytes Small sporangia Liverworts Possess stomata Primitive ‘vascular system’: Leptoids – sugar Hydroids – water Protonema -> Buds -> Apex -> Sporangia Mosses Hornworts Simple gametophytes Large, plate-like chloroplasts Lack of transport system Symbiotic fungal relationship
Vascular Plant Clades Lycophytes Dichotomous roots Microphylls Sporangia – Structures called Strobili, Sporophylls Horsetails Megaphylls Whisk Ferns Small Scales or Small Megaphylls Gametophytes live underground, rely on symbiotic relationship with fungi Leptosporangiate ferns Sporangia appear on stalk, undersides of leaves in bundles called Sori Possess true leaves, roots, and stems Megaphylls Only lycophytes have dichotomous roots.
All seedless plants (both nonvascular and vascular) require water in order for the sperm to successfully reach the egg.