Green Algae

1. Green Algae Domain Eukarya Kingdom Plantae Phylum Chlorophyta

2. Looking Back at Bio 115 Cellular Structure (cell = unit of life)…one or many! Metabolism = Homeostasis (PSN, Resp, N2fix, ferment, etc.) Growth = irreversible change in size Reproduction…failure = extinction Acclimatization-short term responses = behavior Adaptation-long term responses = evolution The Organism as a Unit of Life

3. Lumpers Splitters Plantae Protista Plantae Shifting Kingdoms

4. 8 5 3 2 1 Extant How Many Kingdoms? Multicellular Animals Archezoans Slime Molds Archaebacteria Protozoans Bryophytes Myxozoans True Fungi Chrysophytes Tracheophytes Euglenoids Brown Algae Bacteria Red algae Green Algae Kingdom Plantae is a clade Extinct Long Time with Prokaryotes only Original Cell

5. Plants as a Clade • Photosynthetic Organisms: Unifying features • Cellulose walls glued together with pectin • Chlorophyll a and b, xanthophylls, carotenoids • Store starch • Standard plant chloroplasts, mitochondria, golgi, etc. • Most have Diplohaplontic (sporic) life history • Most have Oogamous gametes

6. No multicellular diploid: haplontic No multicellular haploid: diplontic SYNGAMY mitosis differentiation 1N 2N differentiation mitosis MEIOSIS Generic Life Cycle gametes zygote germination gametangia mitosis differentiation Gametophyte Sporophyte differentiation sporangium mitosis germination spores sporocyte When both haploid and diploid multicellular bodies are formed the life cycle is diplohaplontic

7. + – ¢ ¢ ™ ™ Evolution of Gametes for Syngamy: Isogametes - Anisogametes - Oogametes Evolution of Life Histories: multicellularity and sex Unicellular (neither diplontic or haplontic…but taking both “shortcuts”) Diplontic (no multicellular haploid) Haplontic (no multicellular diploid) Diplohaplontic (both haploid and diploid multicellular forms) Sequence unclear: elaborations vs reductions? Multiple pathways in different groups?

8. cell wall vacuole cell membrane cytosol mitochondria chloroplast nucleus Outgroup for your cladogram: Chlorella http://www.lifesciences.napier.ac.uk/JK/algalweb/chlorell-b2.jpg starch

9. Chlamydomonas flagella contractile vacuole eyespot http://www.unap.cl/~cbrieba/common/chlamydomonas.jpg cellulosic wall nucleus cell membrane mitochondria cytosol starch chloroplast pyrenoid http://universe-review.ca/I10-23-chlamydomonas.jpg

10. http://www.isis.de/members/~ralfwagner/Bilder/Chlamydomonas_spec_Zygote.jpghttp://www.isis.de/members/~ralfwagner/Bilder/Chlamydomonas_spec_Zygote.jpg Chlamydomonas cells of opposite mating type join in syngamy to form a zygote which develops a thick wall as a hypnospore. Upon return to better conditions, the zygote undergoes meiosis and releases flagellated cells of both mating types. http://www.biology.wustl.edu/faculty/images/goodenoughcaption.jpg

11. http://www.isis.de/members/~ralfwagner/Bilder/Chlamydomonas_spec_Zygote.jpghttp://www.isis.de/members/~ralfwagner/Bilder/Chlamydomonas_spec_Zygote.jpg http://www.biology.wustl.edu/faculty/images/goodenoughcaption.jpg SYNGAMY gametes zygote germination mitosis gametangia mitosis differentiation differentiation is it gametic? (diplontic) 1N 2N Gametophyte Sporophyte definitely zygotic (haplontic) differentiation differentiation sporangium mitosis mitosis germination spores sporocyte MEIOSIS http://www.isis.de/members/~ralfwagner/Bilder/Chlamydomonas_spec_Zygote.jpg Life Cycle of Chlamydomonas http://www.unap.cl/~cbrieba/common/chlamydomonas.jpg

12. http://www.microscopy-uk.org.uk/mag/imgjan01/Zygote3.jpg Cosmarium zygotes

13. Life Cycle of Cosmarium http://www.isis.de/members/~ralfwagner/Bilder/Cosmarium_tetraophthalmus.jpg http://www.microscopy-uk.org.uk/mag/imgjan01/Zygote3.jpg http://www.microscopy-uk.org.uk/mag/imgjan01/Zygote3.jpg SYNGAMY gametes zygote germination mitosis gametangia mitosis differentiation differentiation is it gametic? (diplontic) 1N 2N Gametophyte Sporophyte definitely zygotic (haplontic) differentiation differentiation sporangium mitosis mitosis germination spores sporocyte MEIOSIS http://www.isis.de/members/~ralfwagner/Bilder/Cosmarium_tetraophthalmus.jpg

14. Ulva lactuca thallus http://bio59000.free.fr/Photosbio59000/Biovegetale/Algues/Ulva%20lactuca.gif

15. syngamy zygote + – + – + – meiosis – + Ulva life cycle There are three isomorphic thalli: isogametes Some species of Ulva are anisogamous. settles on substrate 1N 2N Gametophytes Sporophyte settle on substrate holdfast sporocyte Since they are motile, they are also called zoospores. The life cycle is: √ sporic: diplohaplontic gametic: diplontic zygotic: haplontic The meiospores made by the sporophyte are of two mating types.

16. Codium http://massbay.mit.edu/exoticspecies/exoticmaps/images/codium_big.jpg

17. syngamy zygote meiosis The life cycle is: Codium Life Cycle sporic: diplohaplontic gametic: diplontic zygotic: haplontic √ 1N 2N Sporophytes 2 sexes anisogametes holdfast sporangium sporocytes zoospores

18. Oedogonium thallus http://www.plingfactory.de/Science/GruKlaOeko/Teichleben/Algen/Oedogonium%20sp..jpg

19. Oedogonium Here the filaments are out of focus. The asexual zoospore is in focus. http://www.botit.botany.wisc.edu/images/130/Chlorophyta/Oedogonium_Images/Zoospore_MC.low.jpg

20. Oogonium http://www.rbgsyd.nsw.gov.au/__data/page/1810/Oedogonium.gif

21. http://www.csupomona.edu/~jcclark/classes/bot125/resource/graphics/g/chl_oedogonium.jpghttp://www.csupomona.edu/~jcclark/classes/bot125/resource/graphics/g/chl_oedogonium.jpg Oedogonium This is the zoospore, or maybe it is the sperm. Both have the same look! http://www.biologie.uni-hamburg.de/b-online/fo44/18.jpg When both oogonium and antheridium appear on the same filament the alga is homothallic.

22. syngamy meiosis Oedogonium Life Cycle Since antheridia and oogonia are on the same filaments, this species is homothallic. zygote (hypnospore) (in oogonium) sperm empty antheridia 1N 2N egg (in oogonium) chemotaxis Vegetative zoospores can clone the gametophyte The zygote divides meiotically to release 4 zoospores. Zoospores settle down with a holdfast and grow into a filament. This life cycle is haplontic (zygotic).