2. PLANTS EVERYTHING YOU NEVER WANTED TO KNOW BUT NEEDED TO FOR THE AP EXAM

3. 2007-2008 Domain Bacteria Domain Archaea Domain Eukarya Common ancestor Kingdom: Plants Domain Eukarya

4. Land plants evolved from green algae Researchers have identified green algae called charophyceans as the closest relatives of land plants

5. Genetic Evidence Comparisons of both nuclear and chloroplast genes –Point to charophyceans as the closest living relatives of land plants Chara, a pond organism (a) 10 mm Coleochaete orbicularis, a disk- shaped charophycean (LM) (b) 40 µm Figure 29.3a, b

6. Animal vs. Plant life cycle diploid multicellular individual 2n diploid multicellular sporophyte 2n haploid multicellular gametophyte 1n haploid unicellular gametes 1n gametes 1n AnimalPlant alternation of generations meiosis fertilization mitosis fertilization mitosis no multicellular haploid meiosis spores 1n zygote 2n

7. Pollen Pollen eliminated the requirement for water for fertilization –spread through wind & animal

8. Angiosperm: flowering plants

9. Anther Filament Stamen Stigma Style Ovary Carpel Sepal Petal Ovule sepals petals Flower Modified shoot with 4 rings of modified leaves –sepals –petals –stamens male –carpel female stamens carpel adaptations through mutations

10. The life cycle of an angiosperm Figure 30.10 Key Mature flower on sporophyte plant (2n) Ovule with megasporangium (2n) Female gametophyte (embryo sac) Nucleus of developing endosperm (3n) Discharged sperm nuclei (n) Pollen tube Male gametophyte (in pollen grain) Pollen tube Sperm Surviving megaspore (n) Microspore (n) Generative cell Tube cell Stigma Ovary MEIOSIS Megasporangium (n) Pollen grains Egg Nucleus (n) Zygote (2n) Antipodal cells Polar nuclei Synergids Egg (n) Embryo (2n) Endosperm (food Supply) (3n) Seed coat (2n) Seed FERTILIZATION Haploid (n) Diploid (2n) Anther Sperm (n) Pollen tube Style Microsporangium Microsporocytes (2n) Germinating Seed Anthers contain microsporangia. Each microsporangium contains micro- sporocytes (microspore mother cells) that divide by meiosis, producing microspores. 1 Microspores form pollen grains (containing male gametophytes). The generative cell will divide to form two sperm. The tube cell will produce the pollen tube. 2 In the megasporangium of each ovule, the megasporocyte divides by meiosis and produces four megaspores. The surviving megaspore in each ovule forms a female gametophyte (embryo sac). 3 After pollina- tion, eventually two sperm nuclei are discharged in each ovule. 4 Double fertilization occurs. One sperm fertilizes the egg, forming a zygote. The other sperm combines with the two polar nuclei to form the nucleus of the endosperm, which is triploid in this example. 5 The zygote develops into an embryo that is packaged along with food into a seed. (The fruit tissues surround- ing the seed are not shown). 6 When a seed germinates, the embryo develops into a mature sporophyte. 7

11. From Ovary to Fruit A fruit –Develops from the ovary –Protects the enclosed seeds –Aids in the dispersal of seeds by wind or animals

12. Co-evolution: flowers & pollinators

13. Plant Structure, Growth, and Development

15. Figure 39.4 1 Reception 2 Transduction 3 Response CYTOPLASM Plasma membrane Phytochrome activated by light Cell wall Light cGMP Second messenger produced Specific protein kinase 1 activated Transcription factor 1 NUCLEUS P P Transcription Translation De-etiolation (greening) response proteins Ca 2+ Ca 2+ channel opened Specific protein kinase 2 activated Transcription factor 2 An example of signal transduction in plants 1 The light signal is detected by the phytochrome receptor, which then activates at least two signal transduction pathways. 2 One pathway uses cGMP as a second messenger that activates a specific protein kinase.The other pathway involves an increase in cytoplasmic Ca 2+ that activates another specific protein kinase. 3 Both pathways lead to expression of genes for proteins that function in the de-etiolation (greening) response.

16. The bending of a grass seedling toward light –Begins with the plant sensing the direction, quantity, and color of the light Figure 39.1

17. Xylem –Conducts most of the water and minerals –Includes dead cells called tracheids Phloem –Distributes sugars, amino acids, and other organic products –Consists of living cells