Transcript Zygnemataceae

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, N2fix, 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
Bacteria
Bacteria
Bacteria
Archaebacteria
Archaebacteria
Archaebacteria
Archaebacteria
Archaebacteria
Archezoans
Archezoans
Archezoans
Archezoans
Archezoans
Euglenoids
Euglenoids
Euglenoids
Euglenoids
Euglenoids
Chrysophytes
Chrysophytes
Chrysophytes
Chrysophytes
Chrysophytes
Green Algae
Green Algae
Green Algae
Green Algae
Green Algae
Brown Algae
Brown Algae
Brown Algae
Brown Algae
Brown Algae
Red algae
Red algae
Red algae
Red algae
Red algae
Slime Molds
Slime Molds
Slime Molds
Slime Molds
Slime Molds
True Fungi
True Fungi
True Fungi
True Fungi
True Fungi
Bryophytes
Bryophytes
Bryophytes
Bryophytes
Bryophytes
Tracheophytes
Tracheophytes
Tracheophytes
Tracheophytes
Tracheophytes
Protozoans
Protozoans
Protozoans
Protozoans
Protozoans
Myxozoans
Myxozoans
Myxozoans
Myxozoans
Myxozoans
Multicellular
Animals
Multicellular
Animals
Multicellular
Animals
Multicellular
Animals
Multicellular
Animals
Extant
How Many Kingdoms?
Kingdom
Plantae is
a clade
8
5
3
Extinct
2
1
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
mitosis
No multicellular
diploid: haplontic
SYNGAMY
gametes
zygote
gametangia
germination
mitosis
differentiation
differentiation
Gametophyte 1N
2N
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-b2.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
http://universe-review.ca/I10-23-chlamydomonas.jpg
chloroplast
starch
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
SYNGAMY
mitosis
gametes
zygote
gametangia
germination
mitosis
differentiation
is it gametic?
(diplontic)
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
differentiation
Gametophyte
1N 2N
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/imgjan01/Zygote3.jpg
http://www.microscopyuk.org.uk/mag/imgjan01/Z
ygote3.jpg
Life Cycle of Cosmarium
http://www.isis.de/members/~ralfwagner/Bilder/Cosmarium
_tetraophthalmus.jpg
SYNGAMY
gametes
zygote
gametangia
germination
mitosis
differentiation
http://www.isis.de/members/~ralfwagner/
Bilder/Cosmarium_tetraophthalmus.jpg
is it gametic?
(diplontic)
differentiation
Gametophyte
1N 2N
Sporophyte
differentiation
mitosis
germination
differentiation
sporangium
spores
mitosis
sporocyte
MEIOSIS
definitely zygotic
(haplontic)
http://www.microscopyuk.org.uk/mag/imgjan01/Z
ygote3.jpg
mitosis
Ulva lactuca thallus
http://bio59000.free.fr/Photosbio59000/Biovegetale/Algues/Ulva%20lactuca.gif
Ulva life cycle There are three isomorphic thalli:
Some species of Ulva
are anisogamous.
isogametes syngamy
+
–
Gametophytes
+
1N 2N
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
1N 2N
Sporophytes
anisogametes
2 sexes
holdfast
sporangium
sporocytes
zoospores
meiosis
Oedogonium thallus
http://www.plingfactory.de/Science/GruKlaOeko/Teichleben/Algen/Oedogonium%20sp..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/fo44/18.jpg
When both
oogonium and
antheridium appear
on the same
filament the alga is
homothallic.
http://www.csupomona.edu/~jcclark/classes/bot125/resource/graphics/g/chl_oedogonium.jpg
Oedogonium Life Cycle
Since antheridia
sperm
and oogonia are on
the same
filaments, this
species is
chemotaxis
homothallic.
Vegetative
zoospores can
clone the
gametophyte
Zoospores settle down
with a holdfast and
grow into a filament.
syngamy
empty
antheridia
egg
zygote
(hypnospore)
1N 2N
(in oogonium)
(in oogonium)
The zygote
divides
meiotically to
release 4
zoospores.
meiosis This life cycle is
haplontic (zygotic).