BIS 2C “Biodiversity and The Tree of Life” Midterm 2 Study Guide: Plantae Lineage

BIS 2C “Biodiversity and The Tree of Life” Midterm 2 Study Guide: Plantae Lineage The Non-vascular plants-Bryophytes/Embryophytes: 1. Early non-vascular plants including Charates and Coleochaete (outgroup-streptophytes) had phragmoplast, branched filaments, apical growth (meristems), and oogamy. 2. Bryophyte: A small flowerless green plant of the division Bryophyta, which compromises the Mosses (Polytrichum), Hornwort (Anthoceros), and Liverworts. • Traditional name used to refer to all embryophytes (land plants) that do not have true vascular tissue • Not a clade; life characterized by a prominent, independent gametophyte • Gametophyte-haploid dominant (independent/free-living); sporophyte-diploid and dependent (formed on gametophyte) • All bryophytes have rhizoids 3. Streptophytes: • Zygote surrounded by haploid cells • Characteristics before lineage: Phragmoplast, plasmodesmata, apical growth (meristems), branched filaments, oogamy: egg and sperm 4. The haplontic life cycle: • The mature organism is haploid • The zygote is only in the diploid stage • Example: Fungus-Rhizopus Oligosporus 5. The diplontic life cycle: • Mature organism is diploid • The gametes are the only haploid stage • Example: African fish eagle-Haliaeetus vocifer 6. Alternation of generations: • The organism passes through haploid and diploid stages that are both multicellular. 7. All land plants share the following features: • Photosynthetic (Chlorophyll A and B) • Store starch in chloroplasts • Multicellular with alternation of generations • Retain egg on parent plant • Retain fertilized zygote (embryo) on parent plant through early development (embryophytes) • Examples of embryophytes: hornworts, liverworts, mosses, ferns, lycophytes, gymnosperms and flowering plants. • Land plants aka embryophytes have an alternation of generations • The evolution of embryophytes was integrally related to the transition of land. • Evolution of new features including: -Cutide (and associated pores, stomata) -Protected reproductive structures (gametangia, sporangia) -Embryos -Protective spore walls (sporopollenin) -Mutualisms with fungi (mycorrhizae) 8. Life on land advantages: • Better sunlight • More carbon dioxide • Exploring a new niche 9. Life on land disadvantages: • Drying out • Support • UV and photo damage • Transport • Gamete dispersal 10. Mitosis results in a diploid organism. 11. Meiosis results in a haploid organism (spores are haploid) 12. Vegetative Synapomorphies for Embryophytes: • Stomata • Persistently green sporophyte • Tracheids (vascular cells); branching independent sporophyte; rooting structures • Megaphylls; overtopping growth form • Seeds • Flowers; double fertilization 13. Reproductive Synapomorphies for Embryophytes: • Alternation of generations: origin of sporophyte • Antheridia and archegonia • Sporangia • Air-dispersed spores 14. Liverworts: • Rhizoids-“root-like” cells • Epidermis with cuticle (thin-walled cells) • Umbrellas make gametes • Leafy, thalloid, banana-shaped, suction cups (gemmee cups) • Offspring identical to mom • Vegetative/asexual reproduction • Rain causes release of sperm 15. Delay of meiosis in land plants (moss) lead to embryophytes 16. Sporophyte: spore plant 17. Sporangium: spore container 18. Gametophyte: gamete plant 19. Gametangia: gamete containers Vascular Plants: 1. Early clades of vascular plants: • Rhyniophytes • Lycophytes (club mosses, etc.) • Pteridophytes (Ferns and relatives) 2. Vascular plant Synapomorphies: • Sporophyte dominant life cycle -Example: Fern life cycle 3. Hornwort: • Persistent green sporophyte 4. Haploid: • Moss spore (meiosis) • Liverwort and rhizoid • Cell in jacket of antheridium • Moss leafy shoot 5. Moss life cycle: • Stomata appeared • Gametophyte is attached to the ground and photosynthesizing • Haploid (gametophyte)-dominant 6. Non-seed vascular plants (tall and shrubby) at the beginning of the Devonian period. 7. Seed ferns and large trees during the Carboniferous period. 8. Progymnosperms at the Permian era. 9. The fern life cycle: • The fern gametophyte is free living • The fern sporophyte is free living • Both phases are truly independent of one another • Ferns are dependent as an embryo but grow up to be an independent sporophyte • Ferns have dominant sporophyte and mosses have dominant gametophytes • First land plants probably had a gametophyte dominant, alternation of generations life cycle because this is the same life cycle as the mosses, liverworts, and hornworts. • Key features of the fern life cycle: -They have alternation of generations -Gametophyte-independent -Reproduce by using swimming sperm that require water for fertilization -Sporophyte-dominant -Sporophyte independent but first few stages were dependent -Tree fern can get really tall and above ground because the gametophyte generation is small and close to the ground. 10. Xylem: • Transports water and nutrients throughout the plant and also provides structural support. • The xylem has major cell types called tracheids and vessels with thickened cell walls. • Tracheids are thin walls (tubes) in the xylem that lacks perforations in the cell wall that transport water from the soil to the plant. • A tree trunk is made up of tracheid (narrow tubes) and vessels (wide tubes). • Not all plants have vessels. • Tracheids and vessels are joined end on end. • Perforation plates: Large openings in the cell at the ends of vessel elements allow for efficient water flow. • Most of a tree is made up of dead cells//Xylem cells are all DEAD cells. • No energy required for water movements • These conducting cells are dead at maturity • Water movement relies on the properties of water that include cohesion, tension, and adhesion. • Evaporation from leaf surfaces is the main pulling force. • Water in xylem is under negative pressure or tension • Water flow in the xylem is unidirectional-from root to shoot tips 11. Phloem: • Major cells types are sieve tubes and companion cells. • Both are alive but sieve tubes lack nuclei at maturity. • Information is supplied by companion cells • Water flow can be up or down. • Both cell types are thin-walled. • Sieve tubes and companion cells are sister cells and have many plasmodesmatal connections. • Sucrose is imported into system by an active mechanism requiring ATP • Water flows in passively to osmotically balance the system • This creates positive pressure at the sucrose loading end and pushes the solution along the phloem • At the unloading end passive and active mechanisms unload the sugar, flow is not unidirectional • Source cell: • Sink cell: 12. Transpiration-Cohesion-Tension Mechanism: • Water from the roots is pulled up by this tension. At night, when stomata close and transpiration stops, the water is held in the stem and leaf by the cohesion of water molecules to each other as well as the adhesion of water to the cell walls of the xylem vessels and branches. 13. Reconstruction of a Rhyniophyte: • Sporangia • Dichotomous branching • Rhizoids (small root-like structures) • Rhizome (big root-like structure) • Xylem and phloem • Photosynthesize • No leaves • Rhyniophytes had this that was not present in bryophytes: A sporophyte that was branched with terminal sporangia and vascular tissue. 14. Lycophytes: • Club mosses and relatives • Dichotomized stems • Sporangia • Fuzzy and green outgrowths • Makes tons of sporangia 15. Club mosses: • Microphylls: “small” leaves or leaves with a single vein. • Hypothesis of how Microphylls arose: There were a lot of sporangia but as source cells flowed in, some did not undergo meiosis and flattened out and became sterile to form leaves. 16. Seedless vascular plants: • Megaphylls: “large” leaves or leaves with multiple veins. -Overtopping, planation, webbing • Arose by changing dichotomous branching by making one branch dominant (overtopping) and then flattened out (planation) and webbing (large leaves) 17. Lycophytes in coal forests turned into huge trees. 18. Carboniferous period-everything was gigantic. • Lots of growth in all clades Dichotomous Branching Leaves Roots Chloroplast and DNA inversion Rhyniophytes (Psilotum) Yes None No No Whisk Fern Yes Small No Yes *** Horsetails (Equisetum) No Large *** Yes Yes Lycophytes (Club Mosses) Some Small Yes No Most Ferns No Large Yes Yes Seed plants No Large Yes Yes 19. Horsetail fossils: • Large leaves-Megaphylls not Microphylls • Reduced leaves • Whorled leaves (whorl=circle) • Reproductive shoot • Sporangia can be produced on a separate reproductive shoot • Dominant in coal forests • Equisetum-only surviving genus left • Invasive 20. Whisk ferns: • Reduced leaves and loss of roots • Both features=secondary because everyone else in the group has it • Sporangia on branches • Subterranean gametophyte-grow underground • When flooded release sperm 21. Most ferns: • Megaphylls • “Pteriodophytes”-true ferns • Fiddleheads • Water ferns • Grow in or on other plants • Sporangia on back of the leaf • Staghorn-full coverage of brown (sporangia) on underside of the leaf 22. Homospory: • The spores of homosporous plants produce a single type of gametophyte with both male and female reproductive organs. 23. Heterospory: • Heterosporous plants produce two types of spores: a larger megaspore and a smaller microspore; and two types of gametophytes. • Example: Selaginella (Lycophyte) life cycle • The Heterosporous life cycle is a form of alternation of generations • Heterospory involves separate male and female gametophytes • Spores in Heterosporous plants differ in size • Advantages of Heterospory: -Different sizes and numbers of male and female spores -Differential resource allocation between male and female gamete bearing structures (gametophytes) -Helps in male gamete dispersal -Provides a nutritive advantage to the next generation 24. Seed plants-Primary growth/Apical tip growth: • The increase in length of the shoot and the root. It is the result of cell division in the shoot apical meristem. • Occurs from division of a meristem cell or cells at the apex of the shoot or root. • Branches can arise from bifurcation of the tip (dichotomous) or from axillary meristems. • Primary growth in vascular plants produces primary xylem and phloem (in addition to other tissue types). 25. Seed plants-Secondary growth: • Characterized by an increase in thickness or girth (width) of the plant. It is caused by cell division in the lateral meristem. • Occurs through the production of more vasculature • Produced from a lateral meristem or cambium • Ancestral vascular plants could make more xylem but not more phloem • In seed plants the vascular cambium is bifacial (two-faced) • Produces xylem (inside) and phloem (outside) 26. All land plants have two different types of gametes. 27. All spores are a result of meiosis in land plants=haploid 28. All seed plants are Heterosporous. 29. A seed is a combination of a female gametophyte (houses new generation seed) and male gametophyte (carries sperm/pollen). Spores are homosporous Spores are Heterosporous Liverworts Lycophytes Mosses Gymnosperms Hornworts Flowering plants Lycophytes One clade of leptosporangiate ferns Horsetails Whisk ferns Leptosporangiate ferns Seed Plant Groups: Gymnosperms (Naked Seed Plants) and Angiosperms (Flowering Plants) 1. Seed plant Synapomorphies: • Secondary growth in vascular tissue • Formation of bark • Axillary branching • Seeds • Pollen -The Pine Life Cycle xxxxxxx Sporophyte growth Indeterminate sporophyte Apical founder (meristem) cells Branching mechanism Bifacial vascular cambium Liverworts N/A No N/A None No Mosses Apical No Few None No Hornworts Basal Yes N/A None No Lycophytes (Club mosses and relatives) Apical Yes Few Bifurcation No Horsetails Apical Yes Few Bifurcation No Whisk ferns Apical Yes Few Branching No Leptosporangiate ferns Apical Yes Few Varies No Gymnosperms Apical Yes Many Axillary meristem Yes Flowering plants Apical Yes Many Axillary meristem Yes, lost in monocots 2. Seeds provide 75% of the world’s nutrition 3. Sporocyte-spore mother cell 4. Determinant vs. indeterminate (continuous cell perforation) 5. Seeds can undergo dormancy AND provide the next generation with a growth advantage-led to domination of the landscape by seed plants. • Dormancy-plants have a choice to have the next generation right away OR when conditions are better. • This process is very advantageous and allows dominance in the plantae lineage. • Heterospory (microspore and megaspore) arose before seeds. 6. The major groups of living seed plants: • Gymnosperms: Cycads, Ginkgos, Gnetophytes, Conifers • Angiosperms