BIOL 1108 1st EditionExam # 2 Study Guide VI. Evolution of plants, plant structure, and growthLearning Objectives1. Draw and label all the parts of a charophyte algae: The very top leaf-like structures are the blades. The stem-like structure is the stipe. The root-like system is the holdfast. 2. Explain why charophyte algae are relevant when we study plant evolution:They are relevant because they are the closest relative to land plants and they are the initial plant that went through evolution to become land plants. 3. List the four main groups of land plants: Non-vascular, seedless vascular, gemnosperms, and angiosperms.4. Give a time estimate when the four groups evolved: 475mya non-vascular (first land plants), 420 mya vascular plants, 305mya gymnosperms, 130mya angiosperms.5. Compare and contrast the environments in which these 4 groups are mainly found: Non-vascular plants had to be in humid/moist environments. Most species are tropical, but some canbe arctic. Vascular plants can survive in many types of environments if there is ample amount ofnutrients. Their cell walls are strengthened by lignin which form the tracheids in the xylem that allows for water transport. Gemnosperms and Angiosperms need temperate/tropical environments. 6. Explain the problems that each environment poses on it’s inhabitants: In hot/dry environments the inhabitants will have difficulty retaining body water or absorbing any more. Intropical environments, the increased shading can pose a problem for short plants. 8. Read from the cladogram which plant groups are the closest relatives: Charophytes are closest to Embryophytes and Gymnosperms are closest with Angiosperms. 9. List the structures associated with the four groups of land plants and place them on the cladogram: Bryophytes (mosses, liverworts) have cell walls made of cellulose and have turgor. Pterophytes (whiskferns, ferns, horsetails) have true vascular tissue, xylon tissue made of lignin and tracheids. Gemnosperms and Angiosperms have true secondary growth which has more lignin and more support. Gemnosperms have seeds, but Angiosperms have coated seeds, flowers, and fruits.10.Define the following: Plant organ: A structural unit of a particular system that has a specific function. There are vegetative (roots, stems, and leaves) and reproductive (flower, seed, or fruit in angiosperms and cone in Gemnosperms). Primary cell wall: Thin, flexible, and extensible layerformed while the cell is growing. Secondary cell wall: A thick layer on the inside of the primary cell wall formed after the cell is fully grown and is not found in all cell types. It can contain lignin, which strengthens and water-proofs the wall. Primary growth: The lengthening of stems and roots (vertical growth). Secondary growth: The thickening of stems and roots (horizontal growth) which results in the cell division in cambia or lateral meristems. Doesn’t occur until gemnosperms. Apical meristems: Lead to primary growth by its cell division. Lateral Meristems: Cell division here leads to secondary growth. Vascular cambium is a lateral meristem which can produce the secondary xylem(inside) and ploem(outside). Cork cambium is the lateral meristemresponsible for lateral growth of the epidermis and replaces the epidermis of roots and stems. Primary phloem and xylem: Laid out by apical meristems and produced by procambium; phloemare vascular tissues responsible for sugar solution transport; xylem are vascular tissues for waterand mineral nutrient transport. Secondary phloem and xylem: Produced by vascular cambium and have the same function as primary. Bark: The outermost layer of woody stems and roots or all tissues outside the vascular cambium; includes the innermost area of the periderm which replaces the epidermis and acts as a protective covering. 11. List all the plant organs and explain their structure and function: Leaves carry out photosynthesis in vascular plants and release oxygen through a stomata. Stems are the structural support in vascular plants that also transport fluids, store nutrients, and produce new living tissue through the meristems. Roots are the non-leaf and non-node bearing part of the plant body that absorb water and inorg anic nutrients; they also anchor the plant body to the ground for support and help store food and nutrients; they partake in asexual reproduction/vegetative reproduction. 12. List the plant tissue types and explain their structure and function: Dermal tissue: protects and prevents water loss. Found in the epidermis or periderm. Ground tissue: responsible for photosynthesis, food storage, regeneration, support, and protection; made of parenchyma, collenchyma, and sclerenchyma. Vascular tissue: transports water, minerals, and food and is found in the phloem and xylem. 13. List the plant cell types and explain their structure and function: Parenchyma: Form the cell membrane and primary cell wall and are responsible for metabolic activity and storage; theyare generally alive at maturity. Collenchyma: Form the cell membrane and primary cell wall but has unevenly thickened areas; provides flexible support. Schlerenchyma: Form primary cell walls, cell membrane, and secondary cell walls between the membrane and primary cell wall. They are lignified and dead at maturity.14. Compare and contrast primary growth to secondary growth: Primary growth is responsible for the lengthening of roots and stems by apical meristems and secondary growth is the growth in diameter of stems and roots by lateral meristems. 15. Explain the relevance of primary and secondary cell walls for support: Primary cell walls are made of cellulose and are thin and flexible. They are water and gas permeable and allow for flexible support while still allowing for growth. The secondary cell walls are thickened and strengthened by lignin for better structural support. 16.Explain the function of the waxy cuticle and indicate its evolution on the plant cladogram: The waxy cuticle on leaves allows for them to avoid excessive water loss while still permitting some exchange of CO2 and O2 for photosynthesis through the stomatas. They evolved when thefirst land plants were nonvascular plants that grew photosynthetic shoots above the shallow fresh water where they lived. 17. Indicate on a cladogram where key traits are evolved: True roots, vascular tissue, and tracheids evolved after bryophytes. Leaves, vessels, seeds, and pollen evolved after seedless vascular plants. Flowers