Plant Form, Function, and Diversity PDF

Plant Form, Function, and Diversity The Plant Kingdom Plants Characteristics of all plants: Photosynthetic Multicellular Non-motile/fixed in their environment Respond to environment through growth Life Cycle with Alternation of Generations Evolution of Photosynthesis in Eukaryotes Photosynthesis in...

Plant Form, Function, and Diversity The Plant Kingdom Plants Characteristics of all plants: Photosynthetic Multicellular Non-motile/fixed in their environment Respond to environment through growth Life Cycle with Alternation of Generations Evolution of Photosynthesis in Eukaryotes Photosynthesis in Eukaryotes arose through endosymbiosis with photosynthetic bacteria 17 All Photosynthetic Eukaryotic organisms: A. Are in a single, closely related group B. Are in two distinct groupings C. Are in many different supergroups D. Are in all eukaryotic supergroups Evolution of Photosynthesis Many type of eukaryotes carry out photosynthesis - All Archaeplastids - Some Stramenopiles - Some Alveolates - Some Rhizarians - Some Haptists - Some Excavates 17 Photosynthetic organelles in eukaryotes are diverse Photosynthesis in Eukaryotes: A. Arose from a single common ancestor that was photosynthetic B. Evolved multiple times C. Involved multiple instances of symbiosis with cyanobacteria D. Was lost from many lineages Multiple rounds of Endosymbiosis have led to the spread of photosynthesis among Eukaryotes Multicellularity has also arisen multiple times in Eukaryotes Plants Cell Structure Cell Wall - Structural support in nonaquatic environment - Makes cell unable to move, fixed in their environment Specialized Plants Cells: Xylem and Phloem Cylindrical cells that help move liquids within plants Xylem: Transports water from roots to rest of plant Phloem: Transports nutrients from leaves to rest of plant Not found in all types of plants Plants Grow from Meristems Meristem: group of plant cells that can divide to form many different plant tissues Found at tips of branches and roots and in vascular cambrium (in some cases) Vascular Cambria creates woody plants Allows stems to thicken over time with additional layers of xylem and phloem Arose multiple times in plant evolution Plants first evolved on land Closest relative are aquatic green algae (Chlorophytes) First plants were land-based Many unique characteristics of plants are related to survival on land Alteration of Generations All plants cycle between a haploid form and a diploid form during their life cycles One form is dominant, and can be either the haploid or diploid depending on the type of plant Cuticle and Stomata Plants must avoid drying out but must also exchange gasses with the atmosphere for productive photosynthesis. Cuticle: waxy protective layer that prevents drying out, also prevents CO2 uptake Stomata: pores in leaves cuticles that can open and shut to balance Diversity of Plants Bryophytes Lycophytes, Ferns and Horsetails Gymnosperms Angiosperms: Monocots and Eudicots Major Traits in Plant Evolution Alteration of Generations and protected embryos Vascularization (Xylem and Phloem) Seeds and Pollen Flowers and Fruits Bryophytes: Mosses, liverworts, and hornworts Simplest Plants Haploid dominant No Vascular tissue or roots Reproduce with unicellular spores – require a wet environment No stomata, limited cuticle but can tolerate drying out First Vascular Plants: Lycophytes, Ferns, and Horsetails Have xylem and phloem (vascular tissue) Have distinct tissues like roots and leaves Diploid dominant Reproduce with spores Some are woody plants Major Synapomorphies of Plant Evolution Alteration of Generations and protected embryos Vascularization (Xylem and Phloem) Seeds and Pollen Flowers and Fruits First Seed-bearing Plants: Gymnosperm Gymosperm = naked seed Examples: Cycads Ginkos Conifers First Seed-bearing Plants: Gymnosperm Diploid dominant Reproduce with seeds and pollen - Wet environment not required Most use wind dispersal of seeds Flowering Plants: Angiosperms Angiosperm = covered seed Examples: Grasses Wildflowers Deciduous trees Flowering Plants: Angiosperms Produce flowers and fruits Most disperse seeds through interaction with animals Most abundant group Very important as human food source Some Angiosperms are Monocots Single cotyledon leaf Vein in leaves parallel No vascular cambium Examples: Grasses Wheat, rice, corn Some Angiosperms are Eudicots Two cotyledon leaves Veins on leaves webbed Some have vascular cambium Highly conductive xylem – can grow very large Monocots vs Eudicots