BIOL 321 Flashcards
(633 cards)
1
Q
where does the vast majority of primary production occur
A
upper 50m
2
Q
depth of sunlight
A
200m
3
Q
waters oxygen carrying capacity
A
2.5% of air by volume
4
Q
oxygen movement in water
A
300,000X slower than in air
5
Q
Reynolds number
A
Re
intertial : viscous forces
6
Q
low Re
A
highly viscous
small fish in water
all movement requires propulsion (no gliding)
7
Q
Linnaeus taxonomic classification scheme
A
Kingdom Phylum Class Order Family Genus Species
8
Q
Taxon
A
any named group of organisms that is sufficiently distinct to be assigned to a category
9
Q
Monophyletic
A
a group derived from a single common ancestor that contains all descendants of that ancestor
10
Q
paraphyletic
A
group derived from a single common ancestor that does not contain all descendants of that ancestor
11
Q
paraphyletic example
A
Invertebrates, reptiles
12
Q
percent of described species that belong to phylum Chordata
A
5%
13
Q
Largest extinction in history
A
P - T extinction, 250mya
95% of species-level diversity lost
14
Q
Binomic species name
A
Generic name specific name
italicized on computer, underlined by hand
15
Q
Abbreviating species name
A
Generic name can be abbreviated (A. species) after being spelled out once, only if there is not another genera that starts with the same letter
16
Q
Species name with researcher who described it
A
sometimes first name is put after the species name, not underlined/italicized
Balanus amphitrite Darwin
unless described by Linnaeus then species name is followed by L.
may also be followed by date
Euphausia superba, Dana 1858
17
Q
When a species is reclassified
A
descriptors name is placed in brackets Ilyanassa obsoleta (Say)
18
Q
proposed replacement to Linnaean system
A
PhyloCode
rankless
19
Q
domains
A
3 - higher than kingdoms
bacteria
archaea
eukarya
20
Q
kingdoms
A
6 Eubacteria (bacteria) Archaebacteria (Archae) Fungi (Eukarya) Protista (Eukarya) Planti (Eukarya) Animalia (Eukarya)
21
Q
Eukaryote
A
cells contain nuclear and membranes around organelles
22
Q
convergence
A
independent evolution of similar features in species of different lineages
features resemble each other that are not from an LCA
23
Q
Analogous features
A
convergence
24
Q
Plesiomorphic
A
primitive, ancestral, original trait
25
ESTs
expressed sequence tags
26
Ecdysozoa
molting animals
27
2 protostome clades
Ecdysozoa
| Lophotrochozoa
28
Homologous features
ancestral
29
Apomorphic
derived, advanced trait
A novel evolutionary trait that is unique to a particular species and all its descendants and which can be used as a defining character
30
direction of evolutionary change
polarity
| evolving towards ancestral or derived character?
31
classic taxonomy
Evolutionary Systematics
32
Evolutionary Systematics weighting
characters with more phylogenetic information are given more weight
33
how Evolutionary Systematics are constructed
homologous characters used to deduce general relationships
| resemblance taken in to account before completed
34
Evolutionary Systematics and paraphyletic groups
not troubled by
| i.e. groups like Reptilia are ok in classic taxonomy
35
Evolutionary Systematics downfalls
slow
requires experience
lacks objectivity and standardized methodology
36
Phylogenetic Systematics
Cladistics
37
how Cladistics are constructed
only with synapomorphies
38
Cladistics and paraphyletic groups
NOT ok
| all taxa must contain all descendants of an ancestor
39
Cladistic benefits
standardized methods and procedures
accommodates molecular data
does not require experience like Evolutionary Systematics
40
Synapomorphy
shared character derived from common ancestor in which it originated
evolutionary novelties
41
How to construct Cladistics with molecular data
start at same spot along code
compare 1 bp at a time
if b.p.'s are same = no phylogenetically useful info
1 bp difference = 1 evolutionary event
42
Problems with molecular data in Cladistics
deletions/insertions - sequences have to be re-aligned
43
LBA
long branches attract
- rapidly evolving gene sequences produce longer branches that tend to group closely together
- a form of systematic error whereby distantly related lineages are incorrectly inferred to be closely related
- enough changes have occurred that lineages look similar
44
When b.p. changes are believed to have occurred too many times, erasing signs of molecular evolution
Saturated sequence
45
two-branched
biramous
| as in crustacean appendages
46
subtidal
live below tidal line
| rarely exposed to air
47
planktonic
mobile w/ negligible locomotion
subject to currents
drift
48
deposit feeder
ingest sediment, digest organic material as sediment moves through digestive tract
49
single branched
uniramous
| insect appendages exclusively uniramous
50
ectosymbiont
live near or on body of other participant
51
both symbionts benefit
mutualism
52
one symbiont benefits while the other is neither benefited nor harmed
commensalism
53
term for symbiont that benefits in commensalism
commensal
54
Saturation
reduced appearance of sequence divergence that results from reverse mutations, homoplasies (convergence) and other multiple changes occurring at single sites along two lineages
55
symbiont that lives within the body of the other participant
endosymbiont
56
Parasitism
depend on host for life
obligate
may or may not improve hosts activities
57
Ancestral state
the character state exhibited by the ancestor from which current members of a clade have evolved
58
Apomorphy
any derived or specialized character
59
Autapomorphy
a derived character possessed by only one descendant of an ancestor, and thus of no use in discerning relationships among other descendants
60
Clade
a group of organisms that includes the most recent common ancestor of all its members and all descendants of that ancestor
every valid clade forms a "monophyletic" group
61
Cladogenesis
the splitting of a single lineage into two or more distinct lineages
62
Cladogram
pictorial representation of branching sequences that are characterized by particular changes in key morphological or molecular characteristics
63
Derived state
an altered state; modified from ancestral condition
| apomorphic state
64
Homology
characters that have the same evolutionary origin from a common ancestor, often coded for by the same gene
65
Homology is the basis for
all decisions about evolutionary relationships
66
homoplasy
independent acquisition of similar characteristics from different ancestors
67
Monophyletic taxon
a group of species that evolved from a single ancestor and includes all descendants of that ancestor
68
Every valid clade
must form a monophyletic taxon
69
Node
a branching point on a cladogram
70
outgroup
a group of taxa outside the group being studied
71
outgroups are used to
'root' the tree and imply the direction of evolutionary change (polarity)
72
paraphyletic group
group of species sharing an immediate ancestor but not including all descendants of that ancestor
73
parsimony
a principle stating that, in the absence of other evidence, one should always accept the least complex scenario
74
pleisiomorphy
ancestral/primitive character
75
polarity
direction of evolutionary change
76
polyphyletic grouping
incorrect grouping containing species that descended from two or more different ancestors
members do not all share the same immediate ancestor
77
When a gene sequence loses its phylogenetic signal due to numerous base-pair substitutions
saturation
78
sister groups
two groups descended from the same immediate ancestor
79
synapomorphy
derived character that is shared by the LCA and two or more descendants
homologous characters that define clades
80
taxon
any named group of organisms
81
Invertebrate lifestyles
sessile
sedentary
motile
82
invertebrate habitats
majority marine - most hospitable
freshwater - more challenging
terrestrial - most challenging
83
challenges with freshwater habitat
maintaining osmotic pressure
water is often ephemeral
wider temperature fluctuations
84
challenges with terrestrial habitat
avoiding desiccation
retaining water
excreting toxic byproducts (urine)
85
types of benthic habitats (marine or fresh)
epifaunal
infernal
interstitial
86
feeding methods in invertebrates
```
suspension feeding
detritivores
deposite feeders
herbivores
carnivores
```
87
Metazoan pie chart
invertebrates are 95% of Metazoans
88
Invertebrate pie chart
beetles >1/4
flies, bees/wasps, butterflies, other insects, chelicerates, crustacea, molluscs, vertebrates (~1/16), other
arthropods = ~7/8
89
pelagic habitats (marine or fresh)
planktonic
90
Grazing carnivores
exploit sessile organisms
91
Predators
feed on actively motile prey (as opposed to grazing)
92
scavengers
feed on dead organisms (carnivory)
93
types of deposit feeders
selective
| non-selective
94
why is phylogeny important
essential for asking questions about evolution (must know polarity)
95
cladogram
diagram of a phylogenetic hypothesis
| nested sets of sister clades
96
branch point
node
97
multicellularity evolved
from unicellularity multiple times uniquely (at least 7)
98
Animal multicellularity requires
cell adhesion
cell specialization and interdependence
embryonic differentiation
99
Importance of cell adhesion
all cells come from single founder cell (fertil. egg)
| to become multicell. they must attach together
100
Why cell adhesion is not enough
some unicellular organisms attach together as well
101
Importance of cell specialization
```
KEY to multicell.
"Division of labour"
*Intercellular signaling VIP*
organization
otherwise chaos
```
102
Importance of embryonic differentiation
allows cells to become specialized and recruited to form functional body plan
also tells about evolution
103
Tissues
large aggregates of same type of cell
104
Metazoan tissue types
```
epithelial
connective
nervous
muscle
gametogenic
```
105
Epithelial tissue
likely most important
primary interface w/ outside environ.
line internal compartments - determines what goes in and out
106
Epithelia components
```
Apical surface
flagella (not always)
Intercellular junctions
micro-villi (not always)
basal surface
nuclei
basal lamina (not always)
apico-basal polarity
```
107
Apical surface
apical membrane of a polarized cell is the surface of the plasma membrane that faces lumen or outside environment
108
intercellular junction
adherons
contact between cells
enable communication
reduce stress on cell
109
basal lamina
layer of extracellular matrix secreted by epithelial cells, on which the epithelium sits
point of attachment
permeability barrier
110
cell polarity
spatial differences in the shape, structure, and function of cells
111
apical-basal polarity
a specialised apical membrane facing the outside of the body or lumen of internal cavities, and a specialised basolateral membrane localised at the opposite side, away from the lumen
112
Importance of apical-basal polarity
secrete different materials
| have different structures (e.g. flagella)
113
connective tissue
```
collagen
cells not connected in extracellular matrix
'wander around'
structural integrity
(e.g. blood, bone)
```
114
Nervous tissue
specialized to transmit information
neurons have high density and diversity
allow message transmission throughout organism
115
how nervous tissue works
change in potential through the ion channels is carried down the length of the neuron
116
muscle tissue
specialized for shortening
| important for animal movement
117
how muscle tissue works
actin and myosin slide relative to each other
118
Major groups of metazoans
```
Porifera
Cnidaria
Ctenophora
Placozoa
Bilateria
```
119
Porifera and Placozoa shared characteristic
no nerves
| no muscles
120
Metazoan phylogeny hypotheses
1. Porifera, (Placozoa, Cnidaria, (Bilateria, Ctenophora))
| 2. Ctenophora, (Porifera, (Placozoa, (Bilateria, Cnidaria)))
121
Problem with metazoan hypothesis 1
It has a trichotomy
122
trichotomy
3 sister groups following 1 node
| perfectly/fully resolved phylogenies only have 2 sister groups
123
problem with metazoan hypothesis 2
```
just controversial
new data (molecular)
```
124
Porifera habitat
marine and freshwater
125
Porifera lifestyle
sessile adults
| suspension feeders - mostly bacteria, some plankton
126
aquiferous system
interconnected system of water canals
| unique to sponges
127
do sponges have tissues
yes
128
what tissues do sponges have
nerve/muscle - no
connective tissue - yes
epithelial tissue - yes
129
name of sponge epithelial tissue
protoepithelia
130
Protoepithelial tissue
less differentiated than other metazoans
131
Sponge interior compartment
spongocoel
atrium
empty space
132
sponge species
8000
| 98% marine
133
non-self recognition
alloincompatibility
| as in sponges
134
flagellated cells lining spongeocoel
choanocytes
'funnel cells'
collar cells
form choanoderm
135
collar cell functions
generate curent to maintain circulation in/through sponge
capture food particles
capture sperm
136
choanoderm
interior sponge tissue - facing spongocoel
137
collar of collar cells
apical flagellum surrounded by microvilli
138
middle sponge layer
mesohyl
139
wandering cells in mesohyl
archaeocytes
140
Mesohyl
gelatinous
non-living
acellular but containing live cells
141
Archaeocyte features
```
amorphous
amoeboid
wander in mesohyl - cytoplasmic streaming
essential functions
develop into specialized cells
```
142
Archaeocyte functions
```
digest food particles from choanocytes
store digested food
role in non-self recognition
may produce flagellated sperm and egg
role in waste elimination
```
143
Sponge Support Elements
spicules
| fibers
144
Spicule structure
siliceous
| calcareous
145
fiber structure
spongin (collagen-like)
146
secrete spongin fibers
spongocytes
147
secrete spicules
sclerocytes
148
spongocytes and sclerocytes come from what types of cells
archeaocytes
149
sponge water entry
ostium
| porocyte
150
sponge water exit
osculum
151
support element functions
maintain sponge shape
discourage predation
systematics (systematics)
152
dormant sponge structure
gemmule
153
gemmule features
dormant structure
certain times of yr
mostly freshwater, especially temperate latitudes
resistant to desiccation, freezing, anoxia
withstand unfavourable conditions
asexual reproduction - multiple clones
154
formation of gemmule
archaeocytes phagocytize other cells to accumulate nutrients - cluster together w/i sponge - surrounding cells secrete thick protective covering capsule - parent sponge dies - gemmules released in to water - enter metabolic arrest - survive - break open and release cells in favourable conditions
155
Vernalization
many gemmules must spend several months at low T before capable of hatching
156
cells in outer sponge layer
Pinacocytes
157
Pinacocyte features
flattened contractile cells
form pinacoderm layer
line incurrent canals
158
Pinacocyte contraction
major/minor sponge shape change
| regulate flow by changing incurrent opening size
159
levels of sponge construction
basic --> complex
| asconoid, syconoid, leuconoid
160
Increased sponge complexity achieved by
increasing invagination of choanocyte layer away from spongocoel
increased flagellated surface area
161
Majority of sponge types (complexity)
leuconoid
162
sponge Classes
Calcarea
Demospongiae
Hexactinellida
Homoscleromorpha
163
How sponge Classes are defined
chemical composition
| support element morphology
164
Class Calcarea characteristics
```
CaCO3 spicules
only class to include all 3 complexities
only class w/ extant asconoids
```
165
Class Demospongiae characteristics
```
largest class
≥80% of all species
mostly leuconoid
spicules/fibers = spongin and/or silica, some chitin
NO CaCO3
only class w/ freshwater species
```
166
Family Cladorhizidae
```
Demospongiae
carnivorous
most lack ostia, oscula, choanocytes
engulf prey in epithelial cell and new filaments
may have symbiotic bacteria
```
167
Class Hexactinellida features
"Glass Sponges"
syconoid or leuconoid
entire sponge is syncytial
interconnected 6-ray spicules of Si and Chitin
168
Syncytial
multinucleate mass
| not separated in to cells
169
Type of reproduction in sponges
asexual- fragmentation or gemmules/buds
| sexual- sperm and eggs
170
Gamete producer in sponges
many species are hermaphroditic so individuals produce both gametes
171
Sponge sexual reproduction
choanocyte- sperm capture- dedifferentiate to amoeboid form- move sperm to mesohyl- egg fertilized in mesohyl
172
Phylum Placozoa defining characteristics
small, multicellular, amorphous, mobile
no body cavity, digestive system, nervous system
2 layers of ciliated epithelium sandwiching multinucleate contractile cells
173
cells in a Placozoa
~1000 per layer
| ~3000
174
Phylum Placozoa species
only 1 described, poorly understood
Trichoplax adherents
molecular work suggests ~10 unknown
175
Placozoa size
~2mm in lab
| much smaller in field
176
Placozoa genome
smallest of any known animal
| 98 million b.p.'s
177
Placozoa habitat
unknown
178
Placozoa cells
no basal lamina
ventral layer = columnar cells w/ flagella
glandular cells secrete digestive enzyme for extracellular digestion
upper layer contains 'shiny spheres' for defense
dissagregated cells can reform fn animal
regenerate pieces that are cut off
179
Placozoa reproduction
asexual - budding, fragmentation
binary fission
possibly sexual
180
Placozoa mitochondrial genome
largest known
43,079 b.p.'s
more closely related to unicellular organisms?
basal group or secondary loss?
181
Choanoflagellate
```
unicellular heterotrophs
collared, flagellated
look like individual choanocytes
but also form colonies
possibly evolved in to sponges?
```
182
Sponge asexual reproduction
fragmentation
| gemmules
183
sponge fragmentation
bit of sponge body separates, piece of somatic tissue grows in to new organism
184
sponge sex
mostly hermaphroditic (not simultaneously), can switch sex in next spawning season
185
sponge sperm
differentiate from choanocytes or archaeocytes
| broadcast spawn in to surrounding sea water through osculum
186
sponge eggs
differentiate from archaeocytes in mesohyl
187
sponge larvae
released from osculum
flagellated, swimming
allows for dispersal
looks like an olive with short little hairs at end
188
diapause
period of suspended development, especially during unfavorable environmental conditions (e.g. gemmule)
189
Cladorhizidae spicules
hook-shaped spicules on tendrils
| act like velcro, hook on to exoskeleton of prey
190
new species of deep ocean carnivorous sponge
Chondrocladia
| 'harp sponge'
191
Late Jurassic time
145 MYA
192
sponges in Jurassic
siliceous sponge reef belt (hexactinellida), 7000km, anywhere on planet, between NA/Baltica and Gondwana, extinct at end of Jurassic
193
how do sponges persist as sessile organisms
- secondary metabolites
| - intracellular bacterial symbionts synthesizing secondary metabolites
194
secondary metabolites
defence
| may be: unpalatable, toxic, antibacterial
195
BC sponges
Hexactinellid reefs formed by 3 species of glass sponge (not same species as from Jurassic)
discovered in 2005
unique to BC, nowhere else
196
sponge internal communication
allow ions into membrane - potential difference - message propagated through whole body - can create whole body response to external disturbance
197
how can a sponge propagate a message through its whole body
one cell at a time
open and close.. neighbour opens and close.. neighbour..
close all cells - stop flow of water in response to environmental disturbance
198
How Professor George Mackie was able to test membrane potential in sponges
cut up, disagregated cells, they reformed a fleshy clump, put clump on parent sponge, tissue formed around = tumor/graft which an electrode could be attached to
199
skeleton
solid or fluid system permitting muscles to be stretched back to their original length following a contraction
may be protective, supportive as well
200
why is a skeleton necessary
muscles can't do repetitious movement alone
201
muscles can
shorten/relax
202
muscles can not
actively extend themselves
203
how muscles work
antagonize each other
work opposite to each other
e.g. bicep, tricep
204
aquatic animal skeleton
many use fluid for muscle interaction
205
why aquatic animals can use liquid skeletons
don't need extra structure/support like terrestrial organisms (gravity, lack of buoyancy)
206
hydrostatic skeleton requirements
cavity w/ incompressible fluid
cavity surrounded by flexible outer membrane (deformable)
constant fluid volume
deformable covering or antagonistic muscles
207
why incompressible fluid is important for a hydrostatic skeleton
to transit pressure changes in all directions
208
additional hydrostatic skeleton requirement if progressive locomotion is to occur
animal must be able to form temporary attachment to substrate
209
cnidaria defining characteristic
secretion of complex intracellular organelles called cnidae; planula larvae
210
Cnidaria habitats
aquatic - marine and freshwater
| by far greatest diversity in ocean
211
Cnidaria marine habitats
benthic and/or pelagic
| most cycle between both, some spend whole life in one or other
212
Cnidaria lifestyle
solitary and/or colonial
sessile/sedentary and/or mobile
predatory (some contain photosynthetic symbionts)
213
Cnidarian species
>11,000
| >99% marine
214
cnidaria body plans
```
medusa
polyp
some have both as stages
some have both at once
some are only one stage
```
215
Cnidaria major characteristics
true gut (carnivore)
diploblastic
radial symmetry (all life history stages)
nerve net
cnidocytes
alternation of generations (many, not all)
216
cnidaria tissue layers
epidermis
gastrodermis
diploblastic
217
cnidaria gelatinous layer
mesoglea
218
mesoglea
gelatinous
nonliving
may contain living cells from embryonic ectoderm
219
diploblastic early development
zygote cleavage - 8-cell stage - cleavage - blastula - gastrulation - becomes 2 layers of cells
220
blastula
hollow ball of cells
221
gastrulation
invagination
222
gastrula
```
2 layers of cells
after gastrulation (endoderm and ectoderm)
```
223
space between 2 layers of gastrula cells
blastocoel
224
opening in gastrula
blastopore
225
Cnidarian blastopore
becomes mouth
226
cavity inside of gastrula (inside ectoderm)
Archenteron
| future gut
227
why is radial symmetry appropriate for sessile/sedentary organisms
not moving w/ a leading end
| sitting still- predators/prey can approach from all sides
228
Cnidaria epidermis cell types
```
epitheliomuscle cells
nerve cells
cnidocytes
gland cells
interstitial cells
```
229
epitheliomuscle cells
```
in epidermis of cnidarian
apical side = bona fide epithelial
basal side = muscles w/ actin/myosin
sensory cells
intra-epithelial neurons
```
230
apical surface
facing lumen or external environment
231
cnidarian sensory cells
neurons in epitheliomuscle cells reach up to apical surface
232
cnidarian intra-epithelial neurons
neurons in epitheliomuscle cells are embedded in epithelium (in other Metazoans, below epithelium)
233
basal surface
bottom edge of the cell or tissue adjacent to the basement membrane
234
Cnidarian nerves are arranged
in a nerve net
| appropriate for radial organism transmit stimuli out concentrically to all body parts
235
choanocyte functions (Porifera)
maintain water flow
capture and ingest particles
capture sperm
transform in to sperm (some species)
236
why choanocytes must maintain water flow
bring in food particles, gases, remove waste products (uric acid, CO2)
237
how choanocytes capture particles
caught on sticky mesh between microvilli
238
choanocyte food digestion
intracellular
| often initial digestion then transfer to archeocytes
239
archaeocyte functions
primarily responsible for food digestion
store nutrients
transform in to gametes
synthesize skeletal elements
240
pluripotent cells
very capable of differentiating in to different cell types (e.g. archaeocytes)
241
basic cnidarian body parts
```
mouth (between tentacles)
tentacles
GVC
body stalk
basal disk
```
242
cnidocytes
```
synthesize cnidae (e.g. nematocysts)
nettle/stinging thread
organelle secreted in cnidoblast
discharge explosively
variety of functions
one of most complex intracellular secretion products known
```
243
types of nematocysts
```
>30 described types
many types in one individual
main groups
1. glutinants
2. volvent
3. penetrant
```
244
glutinant nematocysts
tubule has open end containing adhesive material
245
volvent nematocysts
threads that wrap around and capture prey
246
penetrant nematocysts
penetrate through exoskeleton
| tubule has open end with neurotoxins
247
how nematocysts work
```
Ca+ moves in to capsule
increased molality
water drawn in to capsule
pressure increase
pressure discharges capsule
capsule turns inside out
```
248
nematocyst structure
```
round, proteinaceous capsule, open at one end
hinged operculum
cnidocil by opening (trigger)
hollow, coiled tube in capsule (thread)
may contain barbs
```
249
cnidocyte functions
food capture
defense
temporary adhesion to substrate
250
why barbs don't poke in to capsule of cnidocyte
they point in
| cnidae is turned inside out when ejected
251
how symbionts avoid stinging from cnidae
secrete mucus that prevents nematocyst from firing
252
discharged nematocyst
```
cnidocyte
nematocyst capsule
barbs
thread (tubule)
sloughed off - not reusable
regenerated from interstitial cells (stem cells)
```
253
cnidocyte discharge by
chemical and tactile stimulation
| perceived through cnidocil
254
cnidocil
cluster of modified cilia
| hairlike sensory process
255
Cnidaria gastrodermis cell types
nutritive muscle cells
enzymatic gland cells
some cnidarians also have cnidocytes and nerve cells in gastrodermis
256
medusa vs. polyp mesoglea
mesoglea much more hydrated in medusa - thick and jelly-like
257
Cnidarian phylogeny (Classes)
```
Anthozoa s.g. to
Staurozoa s.g. to
Hydrozoa s.g. to
Scyphozoa s.g. to
Cubozoa
```
258
Subphylum Medusozoa
Staurozoa, Hydrozoa, Scyphozoa, Cubozoa
259
Cnidarian classes that have polyp and medusa stage
Hydrozoa, Scyphozoa, Cubozoa
260
Subphylum Anthozoa includes
anemones, corals, sea pens
| used to be called Class
261
another name for epitheliomuscular cells
nutritive cells
262
implication of Cnidaria having only mouth
only one opening
no anus
must expel undigested remains of one meal before consuming more
263
why is the taxonomy we use most parsimonious
1 evolutionary change (acquiring medusa stage) as opposed to 2 changes (loss of medusa in Anth. and 1/2 loss in Staur.)
264
hydrostatic skeleton functions
maintain shape
transmit force of muscle contraction (to produce movement)
protection
265
cnidaria muscles important for hydrostatic skeleton
circular and longitudinal
266
Class Anthozoa characteristics
absence of medusa, operculum, cnidocil
circular mitochondrial DNA, ciliated groove in pharyngeal wall, coelenteron partitioned by sheets of tissue
all marine
267
cnidaria respiratory system
no respiratory structures
268
Anthozoa species
~6000
| 70% of Cnidarians
269
Sea anemone inflation
open mouth, contract longitudinal muscles, expel all water (of h.s. skeleton), results in chewed bubblegum form
270
sea anemone inflation
ciliated siphonoglyphs draw in water, slowly stretches back out - hours - days
mesoglea responds like silly putty - stretches back out slowly
271
Anthozoa reproduction
Asexual - vision, budding, pedal laceration
| Sexual
272
Anthozoa fision
break body in to 2 parts (transverse or longitudinal plane) - reform rest of organism
273
Anthozoa budding
somatic tissue extends in to a bud that differentiates tentacles and other body parts, then separates
274
Anthozoa pedal laceration
common in anemones
| bleb/pinch off part of foot (oral disk) that regrows its parts (form of fragmentation)
275
Anthozoa sexual reproduction characteristics
```
dioecious
gametes arts from gastrodermis
broadcast spawn gametes
fertilization external or internal
free-swimming planula larvae
```
276
dioecious
separate males and females
277
Anthozoa subclasses
Hexacorallia (Zoantharia)
| Octacorallia (Alcyonaria)
278
Hexacorallia
sea anemones- solitary
stony corals - colonial, solitary
tentacles around mouth in multiples of 6
279
mesentaries
sheets in Anthozoa GVC to increase SA
280
Hexacorallia parts
6 pairs of 1º mesenteries
1 pair siphonoglyphs
stony corals have CaCO3 skeleton
281
Hexacorallia corals
scleractinian
| hermatypic or ahermatypic
282
reef-building corals
hermatypic
283
Class Octocorallia
```
sea pens, sea fan, sea whip, soft corals - pipe coral
all colonial
have central axis
8n tentacles, septa
pinnate tentacles
```
284
colonial Hexacorallia
polyps connected via GV - all tissue layers are continuos in a tunnel, GVC is continuous
polyps on top of CaCO3
285
pinnate tentacles
numerous lateral outfoldings (pinnules) along tentacles
| side branches
286
colonial Octocorallia
interconnections lined by gastrodermis
polyps are not full individuals - embedded thick matrix mesoglea (soft coral)
CaCO3 spicules in mesoglea
may have proteinaceous axial skeleton
287
Anthozoa larvae unique
only Cnidarian planula larvae that feed
288
Anthozoa feeding
primarily carnivorous
| transfer food - mouth - tubular pharynx (don't directly to GVC)
289
siphonoglyphs
ciliated grooves from mouth down pharynx
290
Tropical coral reefs
very high biodiversity and biomass
very clear water needed - nutrient poor
unicellular photosynthetic organisms
291
photosynthetic symbionts (corals)
zooxanthellae - dinoflagellates
| zoochlorellae - chlorophytes
292
reef building corals
hermatypic
293
chlorophytes
green algae
294
when zooxanthellae/zoochlorellae 'overproduce'
corals release products as mucus which is used by other organisms
295
photosynthetic unicells reside where in Cnidarian
within gastrodermal cells of host (intracellular symbiont)
296
what do photosynthetic unicells provide Cnidarians
nutrition
| sunscreen molecules
297
Anemone territory defence
```
inflate acrorhagi (fighting tentacles) - normally can't be seen
have very potent nematocysts
```
298
cold water coral groups
```
forests of Octocorallia
reefs of Hexacorallia
no photosynthetic symbionts
very deep
increase niche space
```
299
anthozoa surfaces
```
oral surface (tentacle end)
aboral surface (basal disk end)
```
300
Anthozoa mouth
shaped like a barbell (bilaterally symmetric)
| bells lined with siphonoglyphs
301
mouth in Anthozoa leads to
gullet (esophagus)
302
medusae swimming
contract circular muscles - expel water (jet propulsion)
| no antagonistic muscles - bell 'springs back' and re-expands to original shape
303
why there are receptors in medusa not polyp
motile - must monitor surroundings more carefully
304
polyp vs medusa, GVC
polyp - simple sac
| medusa - interconnected canals
305
polyp vs medusa, reproduction
In cnidarians w/ alternation of generations
polyp - asexual
medusa - sexual
306
Class Hydrozoa characteristics
```
alt. of gen.
greater representation of polyp stage
mesoglea lacks cells
>3000 species
mostly marine
gastrodermis lacks nematocysts
2 subclasses
```
307
medusa body parts
```
mouth - manubrium - stomach
bell
mesoglea
radial canal
ring canal
tentacles
circular muscles
```
308
ring canal
around periphery of bell
309
radial canals
out from stomach to edge of bell (4)
310
manubrium
muscular cylinder at one end
311
medusa surfaces
exumbrellar surface - 'top'
| subumbrella surface - 'underneath', mouth side
312
Subclass Hydromedusa (Hydrozoa)
```
mostly marine
freshwater e.g. Hydra
thick mesoglea
posses velum
gonads develop from epidermis
```
313
velum
muscular shelf of tissue
| goes in towards mouth from edge of medusa
314
velum function
increases speed and agility
restricts aperture - increase water velocity
can open to the side for turning
315
Hydrozoa polyps
majority colonial (modular)
interconnected, continuous GVC
polymorphism
perisarc
316
colonial polyps with specialized polyp types
polymorphism (Hydrozoa)
feeding, reproducing
(can also have 3rd type of polyp, defensive)
317
perisarc
non-living chitinous protective coating around polyps (Hydrozoa)
318
Hydrozoan reproductive polyp produces
medusa
319
hydroids
colonial Hydrozoans that form branching colonies
often have protective coating
e.g. ostrich plume
320
Hydra
freshwater
separate, distinct polyps
may contain zoochlorella
lack medusa
321
Order Siphonophores
```
Hydrozoans
complex colony
pelagic, free floating
polymorphic polyps + polymorphic medusa
very toxic
clustered modules along stem
```
322
Siphonophore example
Portuguese man-of-war
323
Siphonophore body parts
```
float (gas filled)
swimming bells
stem
feeding polyps
tentacles
reproductive medusa buds
```
324
swimming bells, siphonophores
modified medusa
don't produce gametes
jet propulsion
325
Siphonophore genetics
all genetically identical
express different parts of genome
very novel way of achieving complexity
326
Class Scyphozoa
327
local Scyphozoa
Aurelia sp. - moon jelly
328
gastric pouches
have gastrodermis derived gonads (like Anthozoa)
329
rhopalium
8 around margin of bell
| complex set of photoreceptors, gravity receptors, chemo-, mechano-
330
Hydrozoa gonads
arise from epidermis
331
Scyphozoan life cycle
adult medusa -- eggs + sperm -- fertilized egg -- planula larva -- scyphistoma polyp -- strobila -- ephyra -- medusae
332
Scyphozoan reproduction
strobilation
| transverse fission of strobila to form multiple ephyra
333
Scyphozoan budding
budding may occur during scyphistoma stage
334
Scyphistoma
polyp with tentacles
body form that grows from larva
may bud
335
ephyra
'baby medusa'
produced from strobila
genetically identical (from same strobila)
336
Class Staurozoa
```
least known
medusa + polyp
stalked on aboral end
modified tentacles around periphery - anchors
adhesive structures
small, most
```
337
Staurazoa life cycle
no swimming stage
no free medusa
gametes released in seawater
planulae not ciliated (creep)
338
5 major clades of metazoan
```
Porifera
Cnidaria
Ctenophora
Placozoa
Bilateria
```
339
Phylum Placozoa only described species
Trichoplax adherens
340
Trichoplax adherens
```
1883, FE Schulz
smalles metazoan genome
intertidal, warm, marine
very small
amoeba-like
```
341
Placozoa body features
```
ciliated epithelium
contractile cells btw epithelium
no nerve cells
no basal lamina
possible chemical defense cells
enzyme-secreting cells
bona fide intracellular junctions
```
342
Placozoa movement
move via cilia and contractions
343
Placozoa feeding
move over food particle
transient space around particle
secrete digestive enzymes
digest externally
344
Placozoa reproduction
asexual - binary fission, budding
| sexual suspected but not observed
345
earliest Bilateria fossils
trace
~Precambrian-Cambrian boundary
evidence of active burrowing?
346
Bilateral symmetry associated with
actively motile lifestyle
| leading end of body
347
Bilaterian characteristics
two body axes
triploblastic
How genes
348
Bilaterian axes
anterior-posterior (A-P)
| dorsal-ventral (D-V)
349
Bilateria dermal layers
ectoderm
endoderm
mesoderm
350
Hox genes
encode positional identity along A-P axis
351
Functions of Bilateria internal compartments
```
digestion
transport nutrients and gases
hydrostatic skeleton
source/storage of gametes
role in excretion and osmoregulation
```
352
why Bilateria have internal compartments
must provide nutrients to all the different body parts - especially important in large animals
internal compartments allow for specialization of function (unlike GVC in Cnidaria)
353
Types of secondary body compartments in Bilateria
acoelomate
pseudocoelomate
eucoelomate
354
Acoelomate
mesoderm completely fills area between ectoderm/endoderm
| may contain various compartments
355
Bilateria 'Superphyla'
Lophotrochozoa
Ecdysozoa
Deuterostomia
356
Pseudocoelomate
mesoderm only along inside edge of ectoderm - doesn't fill entire body compartment
e.g. nematodes
357
Eucoelomate
epithelium from mesoderm forms separate compartments L/R
control what goes on in body by apical-basal polarity
compartments can specialize
358
epithelium from mesoderm
mesothelium
359
compartments formed by mesothelium in eucoelomate
eucoelom/coelom
360
compartment in pseudocoelomate
pseudocoel
361
concentration of sensor organs at leading end of body
cephalization
362
cephalization =
formation of A-P axis
363
how were taxonomic trees ordered in 1940s
morphology
| embryonic development
364
L. Hyman, 1940 Bilateria tree
Platyhelminthes - Nematoda - (eucoelomate divergence) - two branches
Deuterostomia (Echinodermata, Hemichordata, Chordata)
Protostomia (Mollusca, Arthropods, Annelida)
365
Deuterostomia vs Protostomia, cleavage
D - radial
| P - spiral
366
Deuterostomia vs Protostomia, mesoderm origin
D - endoderm
| P - mesentoblast
367
Deuterostomia vs Protostomia, eucoelom origin
D - enterocoely
| P - schizocoely
368
Deuterostomia vs Protostomia, blastopore fate
D - anus
| P - variable (rarely just anus)
369
germ layer
group of cells that behave as a unit during early stage of embryonic development
give rise to distinctly diff. tissues and/or organ systems
370
key mesoderm derivatives
muscles
| circulatory systems
371
deuterostome formation
enterocoely = evagination of endoderm - club shape - coelomic pouches pinch off - coelomic vesicles
372
Protostome formation
schizocoely =
| mesentoblasts - gradual enlargement and arrangement into compartments
373
mesentoblasts
cluster of cells in protostome
374
Radial cleavage
cleavage planes parallel and perpendicular to cell axis
| daughter cells lie in same plane as mother cells
375
serial cleavage
spindle axes 45º
| at 8-cell stage top cells are smaller
376
Bilateria tree based on molecular studies comparing nucleotide sequences of rDNA
Protostomia - Lophotrochozoa, Ecdysozoa
| Deuterostomia - Echinodermata, Hemichordata, Chordata
377
Superphylum Lophotrochozoa, Phylums
Annelida
Mollusca
Platyhelminthes
(+ others)
378
Superphylum Ecdysozoa, Phylums
Arthropoda
Nematoda
(+ others)
interesting nematodes closer to arthropods than annelids
379
Ecdysozoa characteristics
cuticle (exoskeleton) periodically moulted to allow growth
| no motile cilia/flagella
380
Ecdysozoa sperm
have flagella-like feature but not motile
| NO motile cilia/flagella
381
colinearity
organization of Hox genes in chromosome = order of their expression along AP axis of developing animal
382
Hox genes encode
```
transcription factors (proteins)
Tc factors bind to DNA and restrict downstream gene expression
```
383
Hox gene groups
4 main groups that are similar enough to have originated from single ancestral gene
4 groups unique to Bilateria
384
Radiata Hox genes
2 groups
385
Earth age
>4.5by
386
described species
~1.7 million
387
undescribed species
probably 10 million
388
earliest known unicellular eukaryotes
~2by
389
earliest known Metazoans
```
542-635my
Ediacaran fauna
South Australia
burrow fossils
no hard parts
```
390
best studied invertebrate fossils
Burgess Shale
BC
525 my
391
Phylum Platyhelminthes
Lophotrochozoa
flatworms
free-living freshwater/marine/terrestrial, parasitic
392
free-living terrestrial flatworms
confined to very humid environments
393
parasitic platyhelminths
e.g. tapeworm
| 75% of phylum are parasitic
394
Phylum Platyhelminthes general characteristics
```
bilateral symmetry
triploblastic
cephalization
aceolomate
gut with one opening (GVC)
dorso-ventrally flattened
cerebral ganglia, long nerve cords
prtonephridia
hermaphroditic, complex reproductive system
```
395
Class Turbellaria
free-living flatworms
not true clade
paraphyletic
396
Platyhelminth gut
gut circulates nutrients and gases so it is appropriate to call it GVC
397
Platyhelminth dorso-ventral flattening
no internal tubules for circulatory/gas exchange
gases don't have to travel as far
gas exchange is affected by SA:V ratio
398
Turbellaria body plan
bilaterally symmetric
auricle - ear-like chemosensory structures
eyes - photoreceptors
399
Turbellaria eyes
can not form images
| detect shadows
400
Turbellaria mouth
mid way down ventral surface
| leads to muscular pharynx
401
Turbellaria pharynx
can sometimes be extended out of body for feeding
402
Turbellaria feeding
mostly predators or scavengers
- secrete digestive enzymes
- swallow prey whole
- terrestrial flatworms have unique feeding
403
Turbellaria enzyme digestion
enzymes digested by pharyngeal glands
begin digestion outside body
suck-up semi-digested soup
404
Terrestrial flatworm feeding
grasp prey w/ adhesive secretion
ensnare prey in sticky mucus
neurotoxins
405
tetrodotoxin
binds to Na channels
| blocks action potentials
406
Turbellaria GVC
not a simple sac
| series of interconnected side branches
407
Turbellaria locomotion
ciliary-mucus crawling
muscular crawling
body undulations for swimming
duoglands
408
ciliary-mucus crawling, Turbellaria
secrete mucus layer, beat cilia, swim over secretion
409
Turbellaria duogland
viscid gland (adhesive) + releasing gland, inside of supporting cell
410
Helps turbellarians with muscular crawling and body undulations
parenchyma cells
411
Parenchyma cells
full of water at constant volume
| can act as hydrostatic skeleton
412
ganglia
concentration of neurons
413
Turbellarian nervous system
cerebral ganglia
2 longitudinal nerve cords
Peripheral nerve plexus
414
Protonephridia
hollow cell in excretory system containing a tuft of rapidly beating cilia that serve to propel waste products into excretory tubules
415
Protonephridial functions
osmoregulation (maintain salt, water balance)
| excretion of ammonia (waste product of protein catabolism)
416
Protonephridium structure
invagination in epithelium = duct
end of duct = terminal cell
basal lamina around duct + terminal cell
flagela in middle of terminal cell go down duct
417
flame bulb
name for terminal cell b/c flagella are beating so much it looks like its flickering
418
function of flagella in protonephridial function
beating of flagella expels water down duct
(-) pressure
draw interstitial fluid into terminal cell through cytoplasmic processes
419
function of basal lamina in protonephridial function
size selector - ultrafiltration
| otherwise everything would leave
420
Selective reabsorption
particles that are accidentally lost through terminal cell can be re-absorbed through duct
421
Waste in the protonephridium is released through the
nephridiopore
422
Turbellaria reproduction
Asexual
| Sexual
423
Asexual reproduction, Turbellaria
transverse fission plane
divide body in half - regenerate missing half
common in free-living flatworms
424
Sexual reproduction, Turbellaria
hermaphroditic
internal fertilization
comple m/f reproductive systems
425
Turbellaria male reproductive system
a series of testis - sperm moves down to sperm duct - moved in to seminal vesicle (stored until copulation) - penis - male gonopore (genital pore)
426
Turbellaria female reproductive system
ovary (1 or more pairs) -- oviduct -- yolk glands -- female gonopore -- copulatory bursa (sperm storage)
427
Turbellaria copulation
each worm delivers sperm to the other
428
hypodermic/traumatic impregnation
use stylit to stab in to body and deliver sperm to body interior
429
Phylum Platyhelminthes Classes
"Class Turbellaria" - free-living
Class Trematoda - flukes (endoparasite)
Class Cestoda - tapeworms (endoparasite)
430
Amount of Platyhelminthes that are parasitic
75-80%
431
benefits of being a parasite
protection against predators
| stable, predictable environment
432
Endoparasitism adaptations
Attachment structures
Modified body wall
Strategies to invade new hosts
High reproductive potential
433
why endoparasites need adaptations
maintain preferred position within host
| reproduce - don't want a lot of individuals in single host or host will become compromised
434
Platyhelminthes endoparasite body wall modifications
```
loss of cilia
reduction of musculature
reduction of sensory structures
nutrient absorption
resist host defenses
```
435
why Platyhelminthes endoparasites adapt body wall
no active movement - don't need cilia/muscles and don't need to monitor surroundings
nutrient absorption - live in 'nutrient soup'
436
Platyhelminthes endoparasite strategies to invade new host
complex life cycle w/ definitive and intermediate host
437
definitive host
the host in which the parasite is sexually mature
438
role of intermediate host life stage
parasite is in larval stage
the way in which the parasite is able to invade the definitive host
may have >1 intermediate host
439
Platyhelminthes endoparasite reproductive potential
have many eggs - since chance of getting to definitive host is low
polyembryony - even more eggs
440
polyembryony
asexual duplication of developmental stages
441
Class Trematoda
flukes
2 suckers, pharynx
e.g. Opisthorchis, Schistosome
442
Class Trematoda morphology
```
Mouth at anterior end surrounded by oral sucker
short pharynx below mouth (inside)
ventral sucker
eggs in uterus (about 1/3 of body)
ovary
seminal vesicle
testes
Intestinal caeca (from pharynx down sides of body)
```
443
Opisthorchis (Clonorchis) sinensis
Oriental Liver Fluke
| Trematode
444
Opisthorchis sinensis life cycle
Adult in human (liver bile ducts)-- eggs released in feces -- eaten by snails -- miracidium (larva) -- sporocyst -- polyembryony -- redia -- polyembryony -- cercariae (free-living) -- fish -- metacercariae (in fish muscle) -- eaten by human
445
O. sinensis miracidium
highly ciliated
| hooklets for burrowing in to snail digestive gland
446
O. sinensis sporocyst
full of germinal balls
absorbs nutrients across wall
each germinal ball develops in to another sporocyst
447
O. sinensis redia
also contain germinal balls
| anterior mouth
448
O. sinensis cercaria
hatch out of snail host
many cercaria from only 1 miracidium (1st larva)
muscular tail - free-swimming
swim to find 2nd intermediate host (fish)
burrow through gills into circulatory system of fish, migrate to muscles
449
O. sinensis metacercaria
round cyst
cyst wall
in fish muscles
450
O. sinensis function of first intermediate host
boost numbers
451
O. sinensis function of second intermediate host
exploit feeding habits of definitive host
| complete life cycle
452
having the male and female reproductive organs in separate individuals
dioecious
453
Schistosoma spp.
2nd most prevalent and destructive human disease
tropical
dioecious (unusual in Platy.)
many species w/ different definitive hosts
454
Schistosoma spp. affects where/how
eggs deposited in mesenteric veins
puncture vein, move through circulatory system
try to reach digestive system
455
Schistosoma spp. life cycle
develop in fresh water -- burrow in to body of snail -- polyembryony -- circariae -- swim around in water -- directly infect definitive host by burrowing in to skin and entering circulatory system
456
mesenteric vein
veins that drain large and small intestines (no direct route out of body to export eggs)
457
swimmers itch
Bird schistosomes - try to burrow in to your skin but bird epithelium is thinner so they can't make it through human skin
458
Trematode life stages that undergo polyembryony
sporocyst
| rediae
459
results of Trematode polyembryony
genetic clones
| exploit intermediate host to enhance fecundity (fertility) of parent worms
460
Trematode polymorphism
1 instance found of soldier and reproductive polymorphs (rediae)
soldier is much smaller, non-reproductive, large mouth, very active, attacks non-clonal individuals that may have also invaded host
461
Class Cestoda morphology
```
anterior hooks
2 anterior suckers (look like eyes)
NO mouth
neck
strobila (proglottids)
```
462
generative region of Class Cestoda
duplicative trunks bud off from neck
463
Anterior end of Cestoda
scolex = hooks + suckers
464
Class Cestoda characteristics
typically vertebrate definitive host
hooks on to digestive tract
fertilization can occur between separate proglottids
465
proglottid
duplicative trunk section
contains complete M&F reproductive structures
strobila is the combined set of proglottids
when filled w/ eggs, break off terminally
466
Taenia life cycle
adult tape worm in carnivore -- proglottids -- feces on ground -- eaten by herbivore -- oncosphere (egg) -- hatches -- burrows through gut wall -- cysticercus -- eaten by carnivore (e.g. wolf)
467
Taenia oncosphere
4 central hooks for burrowing through herbivore gut wall
468
Taenia cysticercus
still looks egg-shaped, encysted in herbivore
excess scolex inside definitive host in digestive lumen
scolex latches on
469
encyst
enclose or become enclosed in a cyst
| excyst - escape from cyst
470
Echinococcus sp.
```
Cestoda
2-3mm long
adult has 3-4 proglottids
carnivore def. host (usually wolf/coyote)
hydatid cyst
```
471
Hydatid cyst
unique to Echinococcus sp.
| terminal proglottid is a HUGE ball filled w/ cystocercai undergoing polyembryony
472
Phylum Annelida lifestyles and habitats
motile, sessile, sedentary
| marine, freshwater, terrestrial
473
Significant innovations in the Annelid body plan development
```
gut w/ mouth + anus
metamerism
eucoeloms
gut muscularization
blood vascular system
```
474
Annelid gut
bidirectional: mouth - anus
| allows specialization of different digestion steps, increases digestions efficiency, appropriate for active lifestyle
475
Annelid metamerism
duplication of trunk segments
| generation zone btw last metamere and pygidium
476
pre-Annelid ancestor morphology
prostomium - trunk - pygidium
| mouth - digestive tract - anus
477
Annelid post-metameric ancestor morphology
prostomium - peristomium - 4 metameres - regeneration zone - pygidium
mouth - digestive tract - anus
478
Annelid eucoelomic compartments
2 compartments around gut lined w/ mesoderm
| connected by dorsal/ventral mesentaries
479
1st segment of Annelid
peristomium
480
Annelid gut muscularization
increased digestion efficiency by being able to move material down gut while organism remains stationary
481
Annelid coelomic compartments interior
lined w/ cilia to circulate gases, maintain homogeneity rather than allowing gradient to form at surface so that diffusion will continue
482
mesentery
double layer of mesothelium mid-dorsally and mid-ventrally between coelomic compartments (in each metamere)
483
Annelid last segment
pygidium
| not a metamere
484
Annelid blood vascular system
convey nutrients/gases between metameres through dorsal/ventral blood vessels
also segmental blood vessels
485
segmental blood vessels
each metamere has blood vessels between d/v blood vessels in each coelomic compartment
486
Annelid blood movement
dorsal blood vessel is lined with epitheliomuscle cells that pump it
487
Functions of coelomic compartments, Annelids
circulation of nutrients and gases
hydrostatic skeleton
role in excretion, osmoregulation
storage of gametes
488
Annelid hydrostatic skeleton
metamerism aids the ability to thrust - change shape of body w/o allowing pressure to be conducted to rest of body
489
Peristaltic Burrowing
alternation of circular + longitudinal-muscle-contraction waves
Forward movement produced by contraction of circular muscles, which elongates body; contraction of longitudinal muscles shortens and anchors body
490
Needed for peristaltic burrowing
fluid-filled coelom (hydrostatic skeleton)
circular + longitudinal muscles
Setae (chaetae)
491
Setae
chitinous bristles
important in locomotion
diagnostic of Annelids
492
Annelid excretion
dorsal bv is leaky fluid passes through basal lamina-- circulates through coelomic comp. - in to metanephridium - out of body
493
Annelid excretion, basal lamina
ultrafiltration
494
Annelid excretion, metanephridium
tube-like structure in-to coelomic compartment
selective reabsorption
opening to coelom is in a different metamere than opening to external environment
495
metanephridium external opening
nephridiopore
496
functional significance of metameres
facilitate regional pressure differentials (help generate unidirectional thrust)
497
dorsal blood vessel leaky cells
podocytes
498
coelomic compartments gametes
gametes generated by mesothelium
| stored in eucoelom
499
Annelid nervous system
dorsal brain
| ganglionate ventral nerve cord
500
Annelid dorsal brain
2 cerebral ganglia in prostomium
501
Annelid nerve cord
ventrally under v.b.v
| 1-2 ganglia in each metamere
502
How chaetae work
held erect on shortened fat metameres to maintain position in burrow
503
past Annelid taxonomy
Polychaeta s.g. to
Oligochaeta s.g. to
Hirudinea
Oligo. + Hiru = Clitellata
504
groups that didn't fit in past Annelid taxonomy
Pogonophora (tubeworm)
Echiura (spoon worm)
Sipuncula (peanut worm)
505
trouble with past Annelid taxonomy
groups didn't have a clear position
| Polychaeta was not monophyletic (para)
506
New Annelida taxonomy
developed w/ molecular taxonomy
we will focus on
Errantia and Sedentaria
both contain polychaetes
507
Errantia
active lifestyle
| many annelid plesiomorphic traits
508
Sedentaria
-sedentary/sessile
| diverse, derived traits
509
Errantia examples
Nereididae
| Glyceridae
510
Polychaeta
polyphyletic group
511
Sedentaria examples
```
Arenicolidae
Sabellidae
Terebellidae
Siboglinidae
Echiuridae
```
512
Nereididae
Errantid
ragworm
paired, well-developed parapodia on each metamere
high concentration of cephalic sensory appendage
513
Errantia lifestyle
active - burrowing, surface crawling, swimming
| why they have lots of sensory appendages
514
Errantia habitat
marine
515
Errantia morphology
well-developed, similar parapodia on most metameres
eversible, armed pharynx
prominent head appendages - sensory reception
516
Errantid parapodium morphology
2-lobed
| 2 muscular rods w/ bundle of chitinous chaetae
517
Errantid parapodium lobes
dorsal lobe = notopodium
| ventral lobe = neuropodium
518
Errantid parapodium rods
acicula - responsible for back and forth movement (stroke, recovery)
519
Errantid acicula function
traction when crawling
surface area when swimming
(due to the chaetae)
520
Errantid locomotion
```
2-gear
slow crawling
rapid crawling
(stroke, recovery)
parapodia on opposite sides of body are out of phase
stroke propagated down length of body
```
521
Errantid rapid locomotion
lateral body undulations
effective stroking augmented by convex curvatures of body thrusting against medium
convex curve = effective stroke
522
Errantid jaws
at end of everted muscular pharynx
grab/shred/capture prey
fossilized records
523
Glyceridae
Errantid
blood worm
red - hemoglobin
live in burrows - low O2 environment
524
Glyceridae ancestral traits
prostomium
| small parapodia
525
Glyceridae tunnel
interconnected tubes
| anterior end near entry - detect movement - lung out w/ long muscular pharynx
526
Glyceridae jaw
4 jaws at end of everted pharynx, each w/ venom gland
527
Sedentaria lifestyle
sedentary/sessile
| permanent burrows or secreted tubes
528
Sedentaria morphology
reduced parapodia
regional specialization of parapodia
pharynx may evert but not armed
some elaborate head appendages for feeding
529
Arenicolidae
```
Sedentary
'lug worm'
muddy sand substrate
j-shaped burrow
reduced parapodia
no jaws
```
530
Arenicolidae parapodia
only on mid section
neuropodia - reduced to ridge w/ chaetae
notopodium - elaborate dendritic branching gill
531
Arenicolidae pharynx
no jaws
filter feeder
covered w/ stick lapilli - 'mop up' sediment
532
Arenicolidae feeding
anterior at end of J-shaped burrow - peristaltic body movement - pull water in - H2O percolates through sand at head end - escapes through sink hole - leaves behind particles
533
J-shaped burrow 'head end'
'blind end'
534
Arenicolidae waste disposal
back up out burrow entrance - stick anus out - eject fecal material = fecal castings
535
Sabellidae
```
Sedentary
'feather duster worm'
sessile
secreted, proteinaceous tube
find on docks
entire life in tube
```
536
Sabellidae crown
radioles (tentacles) - ciliated, create water currents
capture phytoplankton, carry down central axis to mouth
suspension feeding
537
Sabellidae parapodia
minimal anterior extensions for crawling up/down tube
538
Radiole pigment spot
photoreceptor
| Sabellidae
539
Terebellidae
```
Sedentaria
'spaghetti worm'
surface deposit feeder
under rocks
2 tentacle types
```
540
Terebellidae tube
cemented together local particles (shell debris, sand)
541
Terebellidae parapodia
very small/reduced
542
Terebellidae tentacles
long white - feeding
| red, fine, short - gas exchange
543
Siboglinidae
```
Sedentaria
giant vent worms
previously not known to be annelid
secreted tube
red plume/tentacles
```
544
Siboglinidae morphology
red tentacles - not feeding
opisthosome
trophosome
545
Siboglinidae opisthosome
segmented posterior (metameres) - each has coelomic compart., paired chaetae bundle
546
Purpose of Siboglinidae posterior chaetae
hanging on to tube
547
Siboglinidae trophosome
contains sulphide oxidizing bacteria - intracellular bacteria
548
chemosynthesis metabolic pathway
H2S (sulfide) + O2 -- SO4 (sulfate) + E
| E drives calvin benson cycle -- fix organic carbon
549
Echiuridae
Sedentaria
trunk buried in sediment
deposit feeder
elongate anterior end extends to environment
550
Echiuridae morphology
paired setae
trunk
prostomium - long anterior extension (elongate prostomium homolog)
551
Bonellia
genus in Echiuridae
long, ciliated, forked prostomium
green
552
Echiuridae labelled w/ anti-serotonin antibody
highlife segmentally arranged neurons = metameric pattern of neuronal cell bodies
only preservation of metamerism
553
Annelid reproduction (ancestral)
Dioecious (gonochoristic)
Gametes from mesothelium
Broadcast spawn
External fertilization in seawater
554
Annelid gametes
from mesothelium of eucoelomic compartment
| stored in euceolomic comp.
555
Annelid spawning
broadcast
| gametes escape coelom via coelomoducts or metanephridia
556
Class Clitellata Subclasses
Oligochaeta (earthworms)
Hirudinea
(leaches)
557
Siboglinidae branchial filaments
increase surface area for gas absorption
558
Gases needed for Siboglinidae symbionts
O2
CO2
SO4 (sulphate)
branchial filaments connect to trophosome
559
Marine Annelid reproduction
dioecious
external fertilization broadcast spawn
trochophore larva
560
Marine Annelid gametes
from mesothelium
stored in coelom
escape through coelomoducts or metanephridia
561
Epitoky
morphological transformation into a sexual individual
562
Annelids undergo epitoky
to leave benthic habitat and swim up in water column
563
when do Annelids undergo epitoky
in response to environmental cues, all at same time for reproductive purposes
564
Annelid epitoky - the changes
large eyes (to detect enviro. cue)
parapodia enlarge
ripe gametes in coelomic compartments
regression of gut
565
enlargement of parapodia in epitoky (Annelid)
enlarged for swimming paddles
| chaetae increased for efficiency
566
regression of gut in epitoky (Annelida)
only in some species
| using every bit of energy they can for reproduction (then die)
567
Type of transformation (epitoky, Annelida)
Direct transformation
Posterior transformation
Posterior budding
568
Direct transformation (epitoky, Annelida)
whole worm undergoes transformation and swims up in water column
569
why is epitoky dangerous
the swimming up-column 'in-mass' (swarming) proposes a high predation risk
570
Posterior transformation (epitoky, Annelida)
only posterior transforms -- breaks off -- posterior 1/2 swims up
571
Posterior budding (epitoky, Annelida)
Epitokes bud off of posterior end and swarm up in water column
572
trochophore larva
apical ciliary tuft
stomach, mouth, anus, complete digestive tract
2-3 bands of cilia
feeding or non-feeding
573
trochophore larva circumferential ciliary bands
prototroch - anterior, swimming
| metatroch - posterior, feeding
574
trochophore larva feeding
prototroch effective stroke (down) draws particles toward metatroch -- metatroch effective stroke (up) draws particle in to food groove -- short cilia draw particle to mouth
575
trochophore larval development
begin adding metameres to posterior end (pygidium) - lose cilia - crawl away as juvenile annelid
576
Clitellata characteristics
```
Sednetaria
no parapodia
2 pairs of setae/metamere
hermaphroditic
clitellum
```
577
clitellum
several adjacent metameres swollen with glandular cells
| functions in reproduction
578
Annelid movement
peristaltic burrowing through sediment
| alternating contractions of circular and longitudinal muscles
579
contraction of circular muscles, Annelida
contracting fluid in metamere and pushing anterior forward
580
maintaining position in a burrow
shortened/fattened metameres + erect setae push against sides of burrow
581
oligochaete digestive system
regional specialization
| mouth -- pharynx w/ dilator muscles -- esophagus -- crop -- gizzard -- intestine -- anus
582
Annelid gizzard
breaks up material
| physical maceration
583
Annelid intestine
chemical break-down of material
| absorb material
584
Annelid intestine features in cross section
typhlosole
| chlorogogen
585
typhlosole
infolded gastrodermis in centre - increase surface area for enzymatic gland cells and absorptive cells for digestion
586
chlorogogen tissue
specialized mesothelium
| intermediary metabolism
587
what is intermediary metabolism
glycogen/fat synthesis and storage
hemoglobin synthesis
protein catabolism
urea synthesis
588
importance of urea synthesis
ammonia is toxic - hard to flush out in terrestrial animals
| urea less toxic (but metabolically expensive)
589
Oligochaete reproduction
pseudocopulation
| 2 worms in clitellum secreted 'sleeve of mucus' - transfer sperm to seminal receptacle
590
Oligochaete reproduction post-copulation
clitellum forms hard, proteinaceous cocoon + nutrients -- slips down -- collects egg - slips down -- collects sperm -- slips off anterior end
591
oligochaete reproductive structures
clitellum
male gonopore
female gonopore
seminal receptical
592
invasive earthworms
native worms died from glaciation -- agriculture brought them from Europe/Asia - spread by fishing - damaging forest not adapted for them
593
how earthworms can damage a forest
the plants are adapted to nutrients in the top soil layers - worms mix the nutrients down
594
Hirudinea
```
Sedentaria, Clitellata
leeches, bloodsuckers
no parapodia, setae
clitellum, suckers
hermaphroditic
dorso-ventrally flattened
fixed n metameres
```
595
Hirudinia locomotion
swim and crawl
| "looping"
596
Hirudinia locomotion body features
no setae
anterior/posterior suckers
dorso-ventrally flattened
597
leech looping
posterior sucker attaches to substrate - contract circular muscles - elongate - anterior sucker attaches -- release pos. sucker - contract long. muscles -...
598
Hirudinia swimming
dorsal/ventral undulations
599
Hirudinian parasitism
```
ectoparasitism
attach on w/ anterior sucker
3 jaws
buccal secretions
dilator muscles of pharynx
```
600
Hirudinian jaws
cuticle elaborated/sculted to form cutting blades
| may leave Y-shaped incision on host
601
Hirudinian buccal secretions
topical anesthetic (so host is unaware)
vaso-dilators (expand vessels to increase flow)
anticoagulants (hirudin)
602
Hirudinian pharynx dilator muscles
expand lumen of pharynx - creates negative pressure - blood gets sucked in to body (similar to oligochaete pharynx)
603
Hirudinian digestive system
jaws -- pharynx -- crop -- crop caeca -- intestine -- anus (below anterior sucker)
604
crop caeca
extensions of crop for wall expansion during feeding
605
why do Hirudinia need crop caeca
blood is high H2O - need a lot to get nutrients - have to expand alot to get good meal
606
Hirudinia excretion
metanephridia
607
two smaller Lophotrochozoan groups
Phylum Nemertea
| Phylum Rotifera
608
Phylum Nemertea
```
'proboscis worms'
'ribbon worms'
long, thin, dorso-ventrally flattened, ciliate epidermis
secrete celephane-like tube
highly extensible
predatory
*proboscis
```
609
Nemertea habitat
mostly marine, shallow water benthic, rock or sediment
610
Nemertea movement
motile
muscular/cilia crawling
peristaltic-type movement (deformable body)
611
Proboscis
mesothelium sac lined w/ circular muscle, above mouth, contains extendible proboscis - attached to proboscis retractor muscle - may be barbed and toxin bearing
612
how proboscis is ejected
proboscis sac filled w/ fluid - circular muscle contraction - increased fluid pressure - propel prob. out
613
Nemertine body compartments
Rhynchocoel (prob sac) - mesothelium
| lateral blood vessels - coelomic compartments
614
Nemertine blood vessels
epithelium - true coelomic
exterior lined w/ basal lamina
interior ciliated
apicobasal polarity exactly like miniature annelid compartments
615
Nemertine reproduction
dioecious
transient gonads
broadcast spawn
free swimming larva
616
Nemertine gonads
concentrated cells - repeated clusters of gametes - down length of body, ducts form in reproductive season - broadcast spawn
617
Nemertine larva
trochophore-like
external fertilization
juvenile worm develops inside of larva body -metamorphosis- breaks out - eats larva body
618
Phylum Rotifera
```
'wheel animalcules'
ciliated corona
small 0.1-0.5mm
pseudocoelomate
eutely
some syncytial
lorica
```
619
Rotifer corona use
swimming
| phytoplankton capture
620
pseudocoelomate
secondary body compartment not derived from mesothelium
621
eutely
following development constant n cells - never more - every animal the same
622
lorica
intracellular cytoskeletal elements
meshwork of keratin-like protein fibres
thin/flexible or thick/rigid
623
Rotifer morphology
corona - 3 ciliary bands, mouth, master
trunk - stomach, protonephridia, anus
foot + toes
624
Rotifer cilia
function like trochophore larva (direct food to mouth) through convergence
625
mastax
pharynx with trophi (chitinous plates)
626
Rotifer diversity
swimming, sessile in secreted tube, herbivore, predatory, swim by moveable stiff lorica extensions (plates/scales), colonial
627
Rotifer freshwater survival
protonephridia
cryptobiosis
amictic-mictic life cycle
628
protonephridia role in freshwater survival
help to maintain osmotic balance
629
cryptobiosis
expel all water - survive long time as 'dried up flake' - rehydrate in favourable condition
630
Rotifer life cycle
favourable conditions: amictic female (2n) -- diploid egg -- amictic female --
unfavourable: amictic female - mictic female (2n) - haploid egg - haploid male - fertilized egg (2n) - amictic female
631
amictic
incapable of being fertilized : parthenogenetic : producing eggs that develop without fertilization
632
Rotifer reproduction during favourable conditions
parthenogenesis
633
how amictic/mictic reproduction helps Rotifer survive winter
fertilized eggs can enter diapause
"winter eggs"
"diapause eggs"
thick secreted coating that withstands freezing/dessication
