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

2. 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

3. 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

4. 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

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. 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

7. 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?

8. Electron Cryo Tomography and Reconstruction
Outgroup for a cladogram: Ostreococcus tauri?
Electron Cryo Tomography and Reconstruction

9. Outgroup for a cladogram: Chlorella
cell wall
vacuole
cell membrane
mitochondria
chloroplast
cytosol
nucleus
starch

10. Chlamydomonas flagella contractile vacuole eyespot cellulosic wall
cellulosic wall
contractile vacuole
cell membrane
mitochondria
chloroplast
eyespot
nucleus
cytosol
starch
pyrenoid

11. 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.

12. Best classified as unicellular!
Life Cycle of Chlamydomonas
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)

13. Cosmarium zygotes

14. Best classified as unicellular!
Life Cycle of Cosmarium
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)

15. Ulva lactuca thallus

16. 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

17. Codium

18. √ 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

19. Oedogonium thallus

20. 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.

21. Oogonium

22. Oedogonium
This is the zoospore, or maybe it is the sperm. Both have the same look!
When both oogonium and antheridium appear on the same filament the alga is homothallic.

23. 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).