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Biology 221 Notes Exam III

Biology 221 Notes Exam III. Kingdom Plantae: “Primitive plants”. Characteristics. Photosynthetic autotrophs. Appeared about 476 million years ago. Multicellular Most plants are terrestrial In general display an alternation of generations

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Biology 221 Notes Exam III

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  1. Biology 221 Notes Exam III Kingdom Plantae: “Primitive plants”

  2. Characteristics Photosynthetic autotrophs. Appeared about 476 million years ago. Multicellular Most plants are terrestrial In general display an alternation of generations Seeds & pollen also contributed to the success of plants on land

  3. TheEvolution ofPlants

  4. Plants evolved from green algae (charophytes). EVIDENCE Part I: Both possess rosette cellulose-synthesizing complexes within their cell membranes The enzymes contained within peroxisomes are homologous b/t plants and charophytes The flagella of the sperm of charophytes closely resemble the rare flagella in plants

  5. Plants evolved from green algae (charophytes). EVIDENCE Part II: Cell division is similar in both possess phragmoplasts Genetic evidence is consistent with the morphological data

  6. Charophyte

  7. Real cotton seeds and their fibers at maturity represent each of the rosette terminal complex subunits.

  8. Plant peroxisome

  9. DERIVED characteristics that occur in plants Part I Apical meristems where the growth in plant length occurs. Multicellular dependent embryos

  10. DERIVED characteristics that occur in plants Part II Alternation of generations between a diploid sporophyte and haploid gametophyte. Walled spores produced in sporangia Multicellular gametangia

  11. Apical meristem

  12. Multicellular plant embryo

  13. The evolution of plants involves a decreasing dependence of standing water.

  14. Biodiversity of Bryophytes and Pteridophytes

  15. Bryophytes: Nonvascular PlantsGeneral Info I Small herbaceous plants. There are about 24,700 species. The gametophytes are photosynthetic and the sporophytes are dependent on the gametophytes They are non vascular; diffusion is important for the transport of water and nutrients and thus, they are only up to a few cells thick.

  16. Bryophytes: Nonvascular PlantsGeneral Info II Of the two phases: gametophyte and sporophyte, the gametophyte is the dominant phase. Rhizoids are small delicate structures that anchor the gametophytes of bryophytes to the ground (no roots).

  17. PHYLA OF NON-VASCULAR PLANTS

  18. Phylum Hepatophyta (liverworts). In about 20% of these plants, the gametophytes are flattened and lobed (resembling a liver).

  19. Hepatophyta

  20. Phylum Anthocerophyta (hornworts). These may be representative of the earliest land plants

  21. Anthocerophyta

  22. Phylum Bryophyta (mosses)

  23. Bryophyta

  24. Videos • http://www.youtube.com/watch?v=vXPwc3cw6c0 • http://www.youtube.com/watch?v=jcWYAnmm-QE

  25. Seedless Vascular Plants (Pteridophytes)General Info I Evolved modifications that allowed them to be larger (some extinct species were very large): roots and vascular tissue. Still dependent on damp habitats for reproduction The sporophyte is the dominant phase

  26. Seedless Vascular Plants (Pteridophytes)General Info II These plants can be separated into two categories: homosporous and heterosporous Homosporous plants produce a single type of spore that produces a bisexual gametophyte that subsequently produces eggs and sperm. The sporophytes of heterosporous plants produce 2 types of spores: megaspore produces the female gametophyte that produces eggs & the microspore produces the male gametophyte that produces sperm.

  27. PHYLA OF SEEDLESS VASCULAR PLANTS

  28. Phylum Pterophyta whiskferns (psilophytes) occur in the tropics and subtropics. Simplest of all extant vascular plants with stems but no roots. horsetails (sphenophytes) consist of a single genus Equisetum, with species that are homosporous & herbaceous. Ferns are the most abundant of the seedless vascular plants. About 75% of them occur in the tropics. The leaves are referred to as fronds and most of them also have rhizomes.

  29. Pterophyta : Whiskferns

  30. Pterophyta : Horsetails

  31. Pterophyta : Ferns

  32. Phylum Lycophyta (lycophytes). Extant species are very small plants. Common names include club mosses and ground pine.

  33. Lycophyta

  34. Video • http://www.youtube.com/watch?v=eZ40LDWt678

  35. Seed Plants

  36. Seed plants evolved several mechanisms that helped them colonize, survive, and reproduce in more arid environments.

  37. The three most important reproductive adaptations of seed plants Sporophyte dominates in seedless vascular plants & in seed producing plants, the gametophyte is further reduced in size and is dependent on the sporophyte. Seeds

  38. Seeds are GREAT Part I they are multicellular & contain an embryo & its food supply All are heterosporous layers of sporophyte tissue protect the embryo

  39. Seeds are GREAT Part II Inside the megaspore, a female gametophyte develops that produces one or more egg cells. If fertilization occurs, the zygote develops into a sporophyte embryo and the entire ovule develops into a seed. A seed can remain dormant for long periods of time & will germinate if & when conditions are favorable.

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