Domain Eukarya Kingdom Plantae Phylum Chlorophyta Green Algae Domain Eukarya Kingdom Plantae Phylum Chlorophyta

The Organism as a Unit of Life Looking Back at Bio 120 The Organism as a Unit of Life 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

Multicellular Animals Shifting Kingdoms Lumpers Splitters Plantae Protista Plantae 2 3 5 6 8 Bacteria Archaebacteria Archezoans Euglenoids Chrysophytes Green Algae Brown Algae Red algae Slime Molds True Fungi Bryophytes Tracheophytes Protozoans Myxozoans Multicellular Animals

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

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

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

Evolution of Gametes for Syngamy: Isogametes - Anisogametes - Oogametes motile sperm + – sessile egg Evolution of Life Histories: multicellularity and sex Unicellular (neither diplontic nor haplontic?…but taking both “shortcuts”?) What to do about mitosis (asexual)? Diplontic (no multicellular haploid) = gametic Haplontic (no multicellular diploid) = zygotic Diplohaplontic (both haploid and diploid multicellular forms) = sporic Sequence unclear: elaborations vs reductions? Multiple pathways in different groups?

Electron Cryo Tomography and Reconstruction Outgroup for a cladogram: Ostreococcus tauri? http://adapaonline.org/images/biobook_images/ostreococcus_tauri_small.jpg https://genome.jgi.doe.gov/Ostta4/Ostta4.home.html http://schaechter.asmblog.org/schaechter/2015/02/pictures-considered-24-ostreococcus-tauri-the-smallest-known-eukaryote.html Electron Cryo Tomography and Reconstruction https://www.youtube.com/watch?v=2Ohz0eJOGC8

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

Chlamydomonas flagella contractile vacuole eyespot cellulosic wall http://www.unap.cl/~cbrieba/common/chlamydomonas.jpg cellulosic wall contractile vacuole cell membrane mitochondria chloroplast eyespot nucleus cytosol starch pyrenoid http://universe-review.ca/I10-23-chlamydomonas.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.isis.de/members/~ralfwagner/Bilder/Chlamydomonas_spec_Zygote.jpg http://www.biology.wustl.edu/faculty/images/goodenoughcaption.jpg

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

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

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

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

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

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

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

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

Here the filaments are out of focus. The asexual zoospore is in focus. 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

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

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 http://www.csupomona.edu/~jcclark/classes/bot125/resource/graphics/g/chl_oedogonium.jpg When both oogonium and antheridium appear on the same filament the alga is homothallic.

Oedogonium Life Cycle Since antheridia and oogonia are on the same filaments, this species is homothallic. syngamy sperm zygote (hypnospore) (in oogonium) 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. meiosis This life cycle is haplontic (zygotic).