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 115
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 Long Time with 1
Archaebacteria
Archezoans
Multicellular Animals
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 ™ ™ + –
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. Outgroup for your cladogram: Chlorella
cell wall
vacuole
cell membrane
mitochondria
chloroplast
cytosol
nucleus
starch

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

10. 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.

11. Life Cycle of Chlamydomonas
SYNGAMY
zygote
Sporophyte
Gametophyte
sporangium
sporocyte
spores
gametangia
gametes
germination
mitosis
differentiation 1N 2N
MEIOSIS
is it gametic?
(diplontic)
definitely zygotic
(haplontic)

12. Cosmarium zygotes

13. Life Cycle of Cosmarium
SYNGAMY
zygote
Sporophyte
Gametophyte
sporangium
sporocyte
spores
gametangia
gametes
germination
mitosis
differentiation 1N 2N
MEIOSIS
is it gametic?
(diplontic)
definitely zygotic
(haplontic)

14. Ulva lactuca thallus

15. 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.
meiosis
sporocyte
The life cycle is: √
The meiospores made by the sporophyte are of two mating types.
sporic: diplohaplontic
gametic: diplontic
zygotic: haplontic

16. Codium

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

18. Oedogonium thallus

19. 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.

20. Oogonium

21. 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.

22. 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).