Green Algae Domain Eukarya Kingdom Plantae Phylum Chlorophyta

Green Algae Domain Eukarya Kingdom Plantae Phylum Chlorophyta

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

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

Original Cell Kingdom Plantae is a clade Extinct h t i w ly e im s on T ng ryote o L ka Pro ae ue Tr i ng Fu he op hy Sl im t e M es M yx old oz s oa ns M A ult ni ic m ell al ul s ar yt es ph yo A lg e ae A lg s te hy ga al en ac Tr Br re G d Re n ow Br so p ry Ch Ba ct A eria rc h A aeb rc ac he te Eu zoa ria gl ns en oi ds Pr ot oz oa ns Extant How Many Kingdoms? 8 5 3 2 1

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

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?

cell wall http: //www. lifesciences. napier. ac. uk /JK/algalweb/chlorell-b 2. jpg Outgroup for your cladogram: Chlorella vacuole cell membrane cytosol mitochondria chloroplast starch nucleus

Chlamydomonas flagella http: //www. unap. cl/~cbrieba/common/chlamydomonas. jpg contractile vacuole eyespot cellulosic wall cell membrane nucleus mitochondria cytosol starch http: //universe-review. ca/I 10 -23 -chlamydomonas. jpg chloroplast pyrenoid

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 http: //www. isis. de/members/~ralfwagner/Bilder/Chlamydomonas_spec_Zygote. jpg

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

Cosmarium zygotes http: //www. microscopy-uk. org. uk/mag/imgjan 01/Zygote 3. jpg

http: //www. microscopyuk. org. uk/mag/imgjan 01/Z ygote 3. jpg Life Cycle of Cosmarium http: //www. isis. de/members/~ralfwagner/Bilder/Cosmarium _tetraophthalmus. jpg SYNGAMY gametes zygote gametangia differentiation http: //www. isis. de/members/~ralfwagner/ Bilder/Cosmarium_tetraophthalmus. jpg is it gametic? (diplontic) Gametophyte 1 N 2 N germination mitosis differentiation Sporophyte differentiation mitosis germination differentiation sporangium spores mitosis sporocyte MEIOSIS definitely zygotic (haplontic) http: //www. microscopyuk. org. uk/mag/imgjan 01/Z ygote 3. jpg mitosis

Ulva lactuca thallus http: //bio 59000. free. fr/Photosbio 59000/Biovegetale/Algues/Ulva%20 lactuca. gif

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

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

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

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

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/fo 44/18. jpg When both oogonium and antheridium appear on the same filament the alga is homothallic. http: //www. csupomona. edu/~jcclark/classes/bot 125/resource/graphics/g/chl_oedogonium. jpg

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