OCN 201 Biology Lecture 7
Marine Animals
Illustration : Ernst Haeckel
I. The Invertebrates
The Animal Family Tree
Bilateria
Radiata
Ancestral Protist
Round Worms
Mollusks
Segmented Worms
Arthropods
Vertebrates
Echinoderms
Cnidarians
Ctenophores
Sponges
Flatworms
PlacozoaNo symmetry
40 animal phyla
32 phyla are multicellular invertebrates
Segmented Worms
Arthropods
VertebratesThe Genome of the Ctenophore
Mnemiopsis leidyi and Its Implications
for Cell Type Evolution
Joseph F. Ryan, Kevin Pang, Christine E. Schnitzler, Anh-Dao Nguyen, R. Travis Moreland, David K. Simmons, Bernard J. Koch, Warren R. Francis, Paul Havlak, NISC Comparative Sequencing Program, Stephen A. Smith, Nicholas H. Putnam, Steven H. D. Haddock, Casey W. Dunn, Tyra G. Wolfsberg, James C. Mullikin, Mark Q. Martindale, Andreas D. Baxevanis*
Introduction: An understanding of ctenophore biology is critical for reconstructing events that occurred early in animal evolution. The phylogenetic relationship of ctenophores (comb jellies) to other animals has been a source of long-standing debate. Until recently, it was thought that Porif-era (sponges) was the earliest diverging animal lineage, but recent reports have instead suggested Ctenophora as the earliest diverging animal lineage. Because ctenophores share some of the same complex cell types with bilaterians (such as neural and mesodermal cells), the phylogenetic position of ctenophores affects how we think about the early evolution of these cell types.
Methods: We have sequenced, annotated, and analyzed the 150-megabase genome of the cteno-phore Mnemiopsis leidyi. We have performed detailed phylogenetic analyses on these new data using both sequence matrices and information on gene content. We conducted extensive genomic inventories on signaling pathway components and genes known to be critical to neural and meso-dermal cell types, among others.
Results: Our phylogenetic analyses suggest that ctenophores are the sister group to the rest of the extant animals. We fi nd that the sets of neural components present in the genomes of Mnemiopsis and the sponge Amphimedon queenslandica are quite similar, suggesting that sponges have the necessary genetic machinery for a functioning nervous system but may have lost these cell types. We also fi nd that, although Mnemiopsis has most of the genes coding for structural components of mesodermal cells, they lack many of the genes involved in bilaterian mesodermal specifi cation and, therefore, may have independently evolved these cell types.
Discussion: These results present a newly supported view of early animal evolution that accounts for major losses and/or gains of sophisticated cell types, including nerve and muscle cells. This evolutionary framework, along with the comprehensive genomic resources made available through this study, will yield myriad discoveries about our most distant animal relatives, many of which will shed light not only on the biology of these extant organisms but also on the evolutionary history of all animal species, including our own.
FIGURES IN THE FULL ARTICLE
Fig. 1. M. leidyi life history and anatomy.
Fig. 2. Previously proposed relationships of the fi ve deep clades of animals.
Fig. 3. Tree produced by maximum-likelihood analysis of the EST set.
Fig. 4. Tree produced by maximum-likelihood analysis of gene content.
Fig. 5. The origin of postsynaptic genes.
Fig. 6. Inventory of myogenic components in M. leidyi.
SUPPLEMENTARY MATERIALS
Materials and MethodsFigs. S1 to S10Tables S1 to S31References
The phylogenetic position of the ctenophore
Mnemiopsis leidyi and its implications regarding
the origin of mesodermal cell types. (A) Adult M. leidyi. (B) Summary of the relationships of the fi ve main branches of animals and the outgroup Choano-fl agellata. (C) Inventory of myogenic specifi cation genes in Mnemiopsis. Components present in the Mnemiopsis genome are in blue, and names are underlined. Absent components are in red. The lack of many of these factors in Mnemiopsis indicates that ctenophore mesodermal cell types are specifi ed differ-ently than in bilaterians, suggesting that they perhaps evolved independently in these two lineages.
READ THE FULL ARTICLE ONLINEhttp://dx.doi.org/10.1126/science.1242592
Cite this article as J. F. Ryan et al., Science 342, 1242592 (2013). DOI: 10.1126/science.1242592
n
u
c
l
e
u
s
A B C
Ctenophora
Choanoflagellata
Placozoa
Porifera
Bilateria
Cnidaria
Wnt/Wg
BMPs/dpp
Shh/hh
FGF
NK2
Mef2
NK3
Lbx
NK4
Snail
Eomes
Gli
Noggin
Six1/4
Slp
Twist
GATA
Eya
MyoG
Myf5
Mrf4
MyoD
The list of author affi liations is available in the full article online.*Corresponding author. E-mail: [email protected]
RESEARCH ARTICLE SUMMARY
13 DECEMBER 2013 VOL 342 SCIENCE www.sciencemag.org 1336
Published by AAAS
(Science 2013)
0.2
Cryptococcus neoformans
Podocoryna carnea
Ptychodera flava
Symsagittifera roscoffensis
Carteriospongia foliascens
Oscarella lobularis
Amoebidium parasiticum
Petromyzon marinus
Strongylocentrotus purpuratus
Halocynthia roretzi
Pleurobrachia pileus
Helobdella robusta
Ephydatia muelleri
Lottia gigantea
Montastraea faveolata
Monosiga ovata
Lubomirskia baicalensis
Crassostrea virginica
Salpingoeca rosetta
Leucetta chagosensis
Sphaeroforma arctica
Boophilus microplus
Drosophila melanogaster
Saccharomyces cerevisiae
Capsaspora_owczarzaki
Aiptasia pallida
Porites astreoides
Terebratalia transversa
Daphnia pulex
Oopsacas minuta
Monosiga brevicollis
Saccoglossus kowalevskii
Cyanea capillata
Anemonia viridis
Amphimedon queenslandica
Hydra magnipapillata
Asterina pectinifera
Clytia hemisphaerica
Acropora palmataAcropora millepora
Euprymna scolopes
Nematostella vectensis
Capitella telata
Phycomyces blakesleeanusRhizopus orizae
Xiphinema index
Batrachochytrium dendrobatidis
Mertensiid sp
Convolutriloba longifissura
Sycon raphanus
Gallus gallus
Nemertoderma westbladi
Spizellomyces punctatus
Oscarella carmela
Anoplodactylus eroticus
Isodiametra pulchra
Mnemiopsis leidyi
Euperipatoides kanangrensis
Schmidtea mediterranea
Hydractinia echinata
Xenoturbella bocki
Suberites domuncula
Metridium senile
Branchiostoma floridae
Echinoderes horni
Ciona intestinalis
Cerebratulus lacteus
Trichoplax adhaerens
Paraplanocera oligoglena
Meara stichopi
Outgroup
Ctenophora
Porifera
Cnidaria
Bilateria
Placozoa
82
9845
44
83
99 99
8843
94
95
93
8485
44
96
96
72
88
77
9897
96
= 100 bootstrapsupport
Fig. 3. Tree produced by maximum-likelihood analysis of the EST Set. The tree was produced from a matrix consisting of 242 genes and 104,840 aminoacid characters. Circles on nodes indicate 100% bootstrap support. Support placing ctenophores as sister to the rest of Metazoa is 96% of 100 bootstrapreplicates.
13 DECEMBER 2013 VOL 342 SCIENCE www.sciencemag.org1242592-4
RESEARCH ARTICLE
asdeterm
ined
bybaa.pl
(25),was
98.2%.In
94.8%
ofcases,asingleEST
mappedcompletely
toasinglescaffold.T
hese
numberssuggestthat
theassemblyis
both
completeandaccurately
assembled.
Characteris
ticsof
theM.leidyiG
enom
e
The
M.leidyigenom
eisam
ongthesm
allest7%
ofgenomes
whencomparedwith
thosecataloged
intheAnimalGenom
eSize
Database(26)
andis
denselypacked
with
gene
sequences.Itencodes
16,548
predictedprotein-coding
loci,w
hich
make
up58%
ofthegenome,andweconservativelyas-
sign
44%ofthesegene
predictions
intohomology
groups
with
non-ctenophores.The
averagelength
ofan
unspliced
M.leidyitranscriptis5
.8kb.Eight
percento
fpredictedgenesareem
bedded
within
othergenes.T
hisn
umberofnestedintro
nicgenes
ishigh
comparedtoothergenom
es(tableS2
),but
may
beinflatedow
ingtoasubsetof
thesebeing
alternativelyexpressedexons.The
levelofrepeti-
tivesequence
intheM.leidyig
enom
eislow
tomoderate,ascomparedtootherm
etazoans
(tables
S3andS4
);thishasmadeitpossibletoproducea
high-qualitygenomeassemblybasedon
paired-
endandmate-pairsequencing
alone.Additional
characteristicsof
this
genomearepresentedin
tables
S5to
S10.
Phylog
enetic
Positio
nof
M.leidyi
TheavailabilityofthecompletegenomeofM.leidyi
hasallowed
usto
improveon
thectenophore
samplingused
inprevious
phylogenom
icanalyses
ofgene
sequence
evolution.Weassessed
twodata
matrices
thatdiffer
inbreadthof
taxonsampling
andfractionofmissing
data:a
“Genom
eSet”that
includesonlydatafro
mcompletegenomes(13ani-
mals,19.6%
missing
data)and
an“EST
Set”that
includespartialgenomicdatafrom
manytaxa
(58
anim
als,64.9%
missing
data).Weanalyzed
both
matrices
byusingmaximum
-likelihood[with
the
GTR+Gmodelasimplem
entedinRAxM
L(27)]
andBayesian[with
theCATmodelasimplem
ented
inPh
yloB
ayes
(28)]m
ethods.T
ounderstand
the
effectofoutgroup
selectionon
ouringroup
topol-
ogy,weincluded
fourdifferentsetsofnonm
etazoan
outgroups(tableS11)ineach
combinationofmeth-
odandmatrix
.Thismultifactorialstrategy
yielded
atotalof1
6analyses
(Table1).
Wefoundno
supportinanyof
theseanalyses
forCoelenterata(Cn,Ct),
Diploblastica(Bi,),or
Placozoa
beingthesister
lineage
totherest
ofanim
als(Tr,)
(Table1andfig
.S1).W
erecovered
broadsupportforasister
relationshipbetween
CnidariaandBilateria(Cn,Bi)andforaclade
ofPlacozoa,C
nidaria,andBilateria(Tr,C
n,Bi).
Maxim
um-likelihoodanalyses
supportthe
place-
mentof
Ctenophoraas
sister
groupto
allother
Bi
Cn
(Cn,
Ct)
(Ct,B
i)(P
o,)
(Ct,)
(Tr,)
(Bi,)
Ct
Tr Po
Bi
Ct
Cn
Tr Po
Bi
Cn
Tr Ct
Po
Bi
Cn
Tr Po
Ct
Bi
Cn
Ct
Po
Tr
Bi
Cn
Ct
Po
Tr
AB
CD
EF
Fig.
2.Previously
prop
osed
relation
shipsof
thefive
deep
clad
esof
anim
als.Thelabelatthe
botto
mofeach
pane
correspondstotheheaderofTable1.(A)Coelenteratahypothesis.(B)Ctenophoraas
sistertoBilateria.(C)
Poriferaassistergroup
totherestofMetazoa.(D)Ctenophoraassistergroup
tothe
restofMetazoa.(E)Placozoa
assistergroup
totherestofMetazoa.(F)Diploblastica
hypothesis.Weseeno
supportinanyof
oura
nalysesforthe
hypotheses
in(A),(E),and(F)a
ndverylittle
supportfor
(B)(see
Table1).Ct,Ctenophora;Po,Porifera;Tr,Placozoa;Cn,Cnidaria;B
i,Bilateria.
Fig.
1.M.leidyilife
historyandanatom
y.(A)A
dultM.leid
yi(about10
cmlong).(B)Close-upvie
wofcombrows.(C)Aboralvie
wofcydippidstage.(D)O
ne-
celledfertilized
embryo.(EtoH)Earlycleavagestages.(I)Gastrulastage.(JtoM)
LaterdevelopmentofM
.leid
yiem
bryo
shownoralsidedown
.Embryosareabout
200mm
.See
thesupplementarymaterialsfora
moredetaileddescriptionofthe
ctenophorebody
plan.[Photocreditfor(A):courtesyofBrunoVellutini]
13DEC
EMBE
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.org
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ICLE
The Animal Family Tree
Bilateria
Radiata
Ancestral Protist
Round Worms
Mollusks
Segmented Worms
Arthropods
Vertebrates
Echinoderms
Cnidarians
Ctenophores
Sponges
Flatworms
PlacozoaNo symmetry
Text
asdeterm
ined
bybaa.pl
(25),was
98.2%.In
94.8%
ofcases,asingleEST
mappedcompletely
toasinglescaffold.T
hese
numberssuggestthat
theassemblyis
both
completeandaccurately
assembled.
Characteris
ticsof
theM.leidyiG
enom
e
The
M.leidyigenom
eisam
ongthesm
allest7%
ofgenomes
whencomparedwith
thosecataloged
intheAnimalGenom
eSize
Database(26)
andis
denselypacked
with
gene
sequences.Itencodes
16,548
predictedprotein-coding
loci,w
hich
make
up58%
ofthegenome,andweconservativelyas-
sign
44%ofthesegene
predictions
intohomology
groups
with
non-ctenophores.The
averagelength
ofan
unspliced
M.leidyitranscriptis5
.8kb.Eight
percento
fpredictedgenesareem
bedded
within
othergenes.T
hisn
umberofnestedintro
nicgenes
ishigh
comparedtoothergenom
es(tableS2
),but
may
beinflatedow
ingtoasubsetof
thesebeing
alternativelyexpressedexons.The
levelofrepeti-
tivesequence
intheM.leidyig
enom
eislow
tomoderate,ascomparedtootherm
etazoans
(tables
S3andS4
);thishasmadeitpossibletoproducea
high-qualitygenomeassemblybasedon
paired-
endandmate-pairsequencing
alone.Additional
characteristicsof
this
genomearepresentedin
tables
S5to
S10.
Phylog
enetic
Positio
nof
M.leidyi
TheavailabilityofthecompletegenomeofM.leidyi
hasallowed
usto
improveon
thectenophore
samplingused
inprevious
phylogenom
icanalyses
ofgene
sequence
evolution.Weassessed
twodata
matrices
thatdiffer
inbreadthof
taxonsampling
andfractionofmissing
data:a
“Genom
eSet”that
includesonlydatafro
mcompletegenomes(13ani-
mals,19.6%
missing
data)and
an“EST
Set”that
includespartialgenomicdatafrom
manytaxa
(58
animals,64.9%
missing
data).Weanalyzed
both
matrices
byusingmaximum
-likelihood[with
the
GTR+Gmodelasimplem
entedinRAxM
L(27)]
andBayesian[with
theCATmodelasimplem
ented
inPh
yloB
ayes
(28)]m
ethods.T
ounderstand
the
effectofoutgroup
selectionon
ouringroup
topol-
ogy,weincluded
fourdifferentsetsofnonm
etazoan
outgroups(tableS11)ineach
combinationofmeth-
odandmatrix
.Thismultifactorialstrategy
yielded
atotalof1
6analyses
(Table1).
Wefoundno
supportinanyof
theseanalyses
forCoelenterata(Cn,Ct),
Diploblastica(Bi,),or
Placozoa
beingthesister
lineage
totherest
ofanim
als(Tr,)
(Table1andfig
.S1).W
erecovered
broadsupportforasister
relationshipbetween
CnidariaandBilateria(Cn,Bi)andforaclade
ofPlacozoa,C
nidaria,andBilateria(Tr,C
n,Bi).
Maxim
um-likelihoodanalyses
supportthe
place-
mentof
Ctenophoraas
sister
groupto
allother
Bi
Cn
(Cn,
Ct)
(Ct,B
i)(P
o,)
(Ct,)
(Tr,)
(Bi,)
Ct
Tr Po
Bi
Ct
Cn
Tr Po
Bi
Cn
Tr Ct
Po
Bi
Cn
Tr Po
Ct
Bi
Cn
Ct
Po
Tr
Bi
Cn
Ct
Po
Tr
AB
CD
EF
Fig.
2.Previously
prop
osed
relation
shipsof
thefive
deep
clad
esof
anim
als.Thelabelatthe
botto
mofeach
pane
correspondstotheheaderofTable1.(A)Coelenteratahypothesis.(B)Ctenophoraas
sistertoBilateria.(C)
Poriferaassistergroup
totherestofMetazoa.(D)Ctenophoraassistergroup
tothe
restofMetazoa.(E)Placozoa
assistergroup
totherestofMetazoa.(F)Diploblastica
hypothesis.Weseeno
supportinanyof
oura
nalysesforthe
hypotheses
in(A),(E),and(F)a
ndverylittle
supportfor
(B)(see
Table1).Ct,Ctenophora;Po,Porifera;Tr,Placozoa;Cn,Cnidaria;B
i,Bilateria.
Fig.
1.M.leidyilife
historyandanatom
y.(A)A
dultM.leid
yi(about10
cmlong).(B)Close-upvie
wofcombrows.(C)Aboralvie
wofcydippidstage.(D)O
ne-
celledfertilized
embryo.(EtoH)Earlycleavagestages.(I)Gastrulastage.(JtoM)
LaterdevelopmentofM
.leid
yiem
bryo
shownoralsidedown
.Embryosareabout
200mm
.See
thesupplementarymaterialsfora
moredetaileddescriptionofthe
ctenophorebody
plan.[Photocreditfor(A):courtesyofBrunoVellutini]
13DEC
EMBE
R20
13VO
L34
2SC
IENCE
www.scien
cemag
.org
1242
592-2
RESE
ARC
HART
ICLE
ctenophores
• Placozoa
• Porifera (sponges)
• Cnidarians (jellyfish, corals, hydroids)
• Ctenophores (comb jellies)
• Flat Worms
• Round Worms
• Molluscs (clams, snails, squid, octopi)
• Segmented Worms
• Arthropods (copepods, crabs, shrimp)
• Echinoderms (sea stars, brittle stars)
Invertebrate Phyla
Placozoa
• Simplest animal?
• Lacks symmetry
• Only four cell types
• No tissues or organs
• Found on surfaces
• Probably feeds on surface algae and bacteria
• Can fold itself to create a digestive pocket
• “Skeleton” may be calcareous or silica spicules, or entirely of the protein collagen
• Benthic -- intertidal to abyssal, all latitudes
• Suspension Feeders (feeding on plankton, bacteria. A few exceptions)
• Large range of cell types, lack of tissue types
• Source of many bioactive compounds
Porifera (sponges)
Diversity in size & shape,Many growth forms
MBARI
Sponge SkeletonsGlass sponge
( Venus’ Flower Basket)
Natural SpongeCalcareous Sponge
collagen
Sponge Anatomy
choanocyte
The Animal Family Tree
Bilateria
Radiata
Ancestral Protist
Round Worms
Mollusks
Segmented Worms
Arthropods
Vertebrates
Echinoderms
Cnidarians
Ctenophores
Sponges
Flatworms
Placozoa
Ctenophores (comb jellies)
Ctenophores (comb jellies)
• All are marine
• Pelagic from 0 to >3000 m (few benthic creepers)
• Have eight rows of cilia (comb rows)
• Carnivorous
• Use tentacles with sticky colloblasts
• Some directly ingest prey (Beroe)
• Can be invasive (e.g., Black Sea)
asdeterm
ined
bybaa.pl
(25),was
98.2%.In
94.8%
ofcases,asingleEST
mappedcompletely
toasinglescaffold.T
hese
numberssuggestthat
theassemblyis
both
completeandaccurately
assembled.
Characteris
ticsof
theM.leidyiG
enom
e
The
M.leidyigenom
eisam
ongthesm
allest7%
ofgenomes
whencomparedwith
thosecataloged
intheAnimalGenom
eSize
Database(26)
andis
denselypacked
with
gene
sequences.Itencodes
16,548
predictedprotein-coding
loci,w
hich
make
up58%
ofthegenome,andweconservativelyas-
sign
44%ofthesegene
predictions
intohomology
groups
with
non-ctenophores.The
averagelength
ofan
unspliced
M.leidyitranscriptis5
.8kb.Eight
percento
fpredictedgenesareem
bedded
within
othergenes.T
hisn
umberofnestedintro
nicgenes
ishigh
comparedtoothergenom
es(tableS2
),but
may
beinflatedow
ingtoasubsetof
thesebeing
alternativelyexpressedexons.The
levelofrepeti-
tivesequence
intheM.leidyig
enom
eislow
tomoderate,ascomparedtootherm
etazoans
(tables
S3andS4
);thishasmadeitpossibletoproducea
high-qualitygenomeassemblybasedon
paired-
endandmate-pairsequencing
alone.Additional
characteristicsof
this
genomearepresentedin
tables
S5to
S10.
Phylog
enetic
Positio
nof
M.leidyi
TheavailabilityofthecompletegenomeofM.leidyi
hasallowed
usto
improveon
thectenophore
samplingused
inprevious
phylogenom
icanalyses
ofgene
sequence
evolution.Weassessed
twodata
matrices
thatdiffer
inbreadthof
taxonsampling
andfractionofmissing
data:a
“Genom
eSet”that
includesonlydatafro
mcompletegenomes(13ani-
mals,19.6%
missing
data)and
an“EST
Set”that
includespartialgenomicdatafrom
manytaxa
(58
animals,64.9%
missing
data).Weanalyzed
both
matrices
byusingmaximum
-likelihood[with
the
GTR+Gmodelasimplem
entedinRAxM
L(27)]
andBayesian[with
theCATmodelasimplem
ented
inPh
yloB
ayes
(28)]m
ethods.T
ounderstand
the
effectofoutgroup
selectionon
ouringroup
topol-
ogy,weincluded
fourdifferentsetsofnonm
etazoan
outgroups(tableS11)ineach
combinationofmeth-
odandmatrix
.Thismultifactorialstrategy
yielded
atotalof1
6analyses
(Table1).
Wefoundno
supportinanyof
theseanalyses
forCoelenterata(Cn,Ct),
Diploblastica(Bi,),or
Placozoa
beingthesister
lineage
totherest
ofanim
als(Tr,)
(Table1andfig
.S1).W
erecovered
broadsupportforasister
relationshipbetween
CnidariaandBilateria(Cn,Bi)andforaclade
ofPlacozoa,C
nidaria,andBilateria(Tr,C
n,Bi).
Maxim
um-likelihoodanalyses
supportthe
place-
mentof
Ctenophoraas
sister
groupto
allother
Bi
Cn
(Cn,
Ct)
(Ct,B
i)(P
o,)
(Ct,)
(Tr,)
(Bi,)
Ct
Tr Po
Bi
Ct
Cn
Tr Po
Bi
Cn
Tr Ct
Po
Bi
Cn
Tr Po
Ct
Bi
Cn
Ct
Po
Tr
Bi
Cn
Ct
Po
Tr
AB
CD
EF
Fig.
2.Previously
prop
osed
relation
shipsof
thefive
deep
clad
esof
anim
als.Thelabelatthe
botto
mofeach
pane
correspondstotheheaderofTable1.(A)Coelenteratahypothesis.(B)Ctenophoraas
sistertoBilateria.(C)
Poriferaassistergroup
totherestofMetazoa.(D)Ctenophoraassistergroup
tothe
restofMetazoa.(E)Placozoa
assistergroup
totherestofMetazoa.(F)Diploblastica
hypothesis.Weseeno
supportinanyof
oura
nalysesforthe
hypotheses
in(A),(E),and(F)a
ndverylittle
supportfor
(B)(see
Table1).Ct,Ctenophora;Po,Porifera;Tr,Placozoa;Cn,Cnidaria;B
i,Bilateria.
Fig.
1.M.leidyilife
historyandanatom
y.(A)A
dultM.leid
yi(about10
cmlong).(B)Close-upvie
wofcombrows.(C)Aboralvie
wofcydippidstage.(D)O
ne-
celledfertilized
embryo.(EtoH)Earlycleavagestages.(I)Gastrulastage.(JtoM)
LaterdevelopmentofM
.leid
yiem
bryo
shownoralsidedown
.Embryosareabout
200mm
.See
thesupplementarymaterialsfora
moredetaileddescriptionofthe
ctenophorebody
plan.[Photocreditfor(A):courtesyofBrunoVellutini]
13DEC
EMBE
R20
13VO
L34
2SC
IENCE
www.scien
cemag
.org
1242
592-2
RESE
ARC
HART
ICLE
lobate
cestid
beroe cydippid
• Named for the stinging cells (cnidocytes)
• Radial symmetry
• Two forms: polyps and medusae
• Asexual and Sexual Reproduction
Cnidarians(anemones, corals, jellyfish)
• Radial symmetry
• Simple Digestive system (blind sac)
• No circulatory, respiratory or excretory systems
• carnivores/detritovores
• Primitive nerve networks
Polyp Medusa
Cnidocytes
• Prey capture
• Turf wars
• Defense
Cnidocytes
toxins
Class Hydrozoa: hydroids and hydromedusaeClass Anthozoa: Sea anenomes, corals, sea pensClass Cubozoa: sea wasps and box jelliesClass Scyphozoa: jellyfish (big jellies)
Jellyfish and fisheries
The Animal Family Tree
Bilateria
Radiata
Ancestral Protist
Round Worms
Mollusks
Segmented Worms
Arthropods
Vertebrates
Echinoderms
Cnidarians
Ctenophores
Sponges
Flatworms
Placozoa
• Turbellarian flatworms are marine, benthic
• Infauna from intertidal to deep sea
• Carnivorous or herbivorous
• Move by cilia or undulations
• Mouth but no anus
• Cephalization
Flatworms (Platyhelminthes)
• Flow-through digestive system!
• Found all over (terrestrial, freshwater, marine)
• VERY abundant free-living in benthic infauna
• Many other types are parasitic
• Many are deposit feeders, detritivores
Roundworms (Nematodes)
The Animal Family Tree
Bilateria
Radiata
Ancestral Protist
Round Worms
Mollusks
Segmented Worms
Arthropods
Vertebrates
Echinoderms
Cnidarians
Ctenophores
Sponges
Flatworms
Placozoa
MAJOR CLASSES
• Bivalvia (Clams, oysters, mussels)
• Gastropoda (snails, nudibranchs)
• Cephalopoda (squid, octupus, nautilus)
Molluscs
• Many burrowing and boring
• Others attach to rocky surfaces
• Suspension feeding or selective deposit feeding
Bivalves Burrowing
boring
• Many with shells (snails, whelks, etc.) some types without shells (e.g. nudibranchs)
• Some planktonic forms (e.g. pteropods)
• Herbivores and carnivores, deposit and suspension feeders
• Have a radula (a toothed scraper)
Gastropods
• Well developed brains and eyes
• Many have ink sacs
• Only one type still has external shell (Chambered nautilus)
• Carnivores; Use radula and beak for tearing food
• Many can rapidly change colors (camouflage, communication)
Cephalopods
The Animal Family Tree
Bilateria
Radiata
Ancestral Protist
Round Worms
Mollusks
Segmented Worms
Arthropods
Vertebrates
Echinoderms
Cnidarians
Ctenophores
Sponges
Flatworms
Placozoa
• Major Class: the Polychaetes
• Mostly benthic, a few planktonic
- predatory epifauna
- tube-dwelling infauna (deposit/suspension feeders)
Segmented Worms (Annelids)
well developed central nervous
system
PolychaetesFood capture & Gas Exchange
tube dwelling
Christmas tree worm
Arthropoda(jointed feet)
• Exoskeleton (protection, leverage)
• Striated Muscle (quick, powerful)
• External Skeleton requires molting
• Herbivores, carnivores, omnivores
Arthropoda: CrustaceaMalacostraca
amphipodsisopodsostracods
mysids
decapod
branchiopods
copepods
Arthropoda
• Vast majority of marine arthropods are crustaceans
• Exceptions: marine insects, chelicerates (e.g., horseshoe crabs, pycnogonids)
halobates
horseshoe crabs
The Animal Family Tree
Bilateria
Radiata
Ancestral Protist
Round Worms
Mollusks
Segmented Worms
Arthropods
Vertebrates
Echinoderms
Cnidarians
Ctenophores
Sponges
Flatworms
Placozoa
• Echino derm = spiny skin
• Most are suspension or deposit feeders, some grazers (e.g., kelp), sea stars also predatory
• From intertidal to abyssal depths, benthic, often have planktonic larvae
• Have tube feet
• Bilaterally symmetric as larvae, adults pentaradially symmetric
Echinoderms
Sea Stars
Brittle Stars
Sea Cucumbers
Sea Urchins
Crinoids
Echinoderms
tube feet
Echinoderms
Questions?