1
Q
Where is the word animal derived from?
A
“Animalus”: means “having breath”
2
Q
What are some characteristics of animals? What is another common name?
A
- eukaryotic, lack cell walls, heterotrophic, motile, multicellular
- AKA Metazoans
3
Q
What does diversity mean?
A
- having different forms types
4
Q
What is taxonomy? How might early and later evolved animals be placed?
A
Taxonomy produces a formal system to name and group species
- animals with recent common ancestry will be grouped more closely, whereas animals with common ancestry further back are placed in different groups as higher taxonomic levels
5
Q
Who was the first to classify organisms on structural similarities?
A
- Aristotle: “ the history of animals” - 350BC
6
Q
Name the two individuals who introduced comprehensive animal naming systems
A
- John Ray: a more comprehensive system
- Linnaeus (current system) : much has changed by principles stayed the same - created a hierarchy system for classification
7
Q
What is linnaeus’ system?
A
- every species has a latinized name composed of two different words (genus and species)
- italicized, genus is capitalized and epithet (species) is lower case
8
Q
True or False: Genus can be re used
A
FALSE:
9
Q
Why is it important to use binomial nomenclature?
A
- because there are many different names for individual organisms
- more precise and consistent than common names
10
Q
What are the different kinds of biodiversity? Why are they important?
A
- taxonomic: variety of species
- ecological: variety of ecosystems (community)
- morphological: genetic diversity
important for conservation!
11
Q
What are the 4 places animals can live?
A
- terrestrial, marine, freshwater, brackish water
12
Q
Describe the two kinds of dwellers in water and their terms
A
benthic: live on sea floor
- sediments/substrate
- infaunal (burrow)
- epifaunal: live on top
pelagic: live in the water column
13
Q
What does it mean for animals to be heterotrophic?
A
- they require external energy sources
14
Q
Describe two kinds of animal interactions
A
- symbion and parasitic
15
Q
What does monoecious and dioceious mean?
A
monoecious: hermaphroditic = two sex organs on one organism
dioecious: separate sexes
16
Q
what does semelparous mean?
A
- dies shortly after reproduction (eg; salmon)
17
Q
Name the 3 ‘parity’s’
A
- oviparity: egg laying animal
- ovoviviparity: eggs hatch inside body, birth live young
- viviparity: births live young
18
Q
What does direct and indirect development mean?
A
- direct: duckling grows into a duck
- indirect: caterpillar first turns into cocoon, then butterfly
- eg; juvenile stage is distinct from adult stage
19
Q
What is the geological time scale? learn the important events that occur!
A
- a time scale since animals first began to develop
- Camels Often Sit Down Carefully Perhaps Their Joints Creak
20
Q
Is evolution linear or branched?
A
- the idea that evolution is linear is a farce! evolution is BRANCHED
21
Q
what is a synapomorphy?
A
- shared derived character states : allows us to develop phylogenetic trees
22
Q
Define homology and homoplasy
A
homology: similar characteristics due to divergent evolution (same common ancestor)
homoplasy: similar characteristics due to convergent evolution ( not recently related; similar environments leads to similar development)
23
Q
What are the 3 kind of phyletic groups?
A
monophyletic: includes recent common ancestor and all of its descendants (ie: clade)
paraphyletic: monophyletic group that excludes some of the descendants (some not all)
polyphyletic: a group consisting of members from two or more non overlapping monophyletic groups (random groups)
24
Q
True or false: simplicity indicates evolutionary complexity
A
FALSE: simplicity does NOT indicate evolutionary complexity
- think sea sponges
25
What are the key transitions in animal architecture?
1. level of organization/complexity
2. body symmetry
3. body cavity organization
4. developmental traits
- protostome vs. deuterostome
26
What are the 5 levels of organization/complexity?
1. protoplasmic level
2. cellular level
3. cell tissue level
4. tissue level
5. organ and organ system level
27
describe the protoplasmic level
- not in animals
eg; unicellular eukaryotes
28
describe the cellular level
- aggregation of cells with differentiated functions
- adhesion between cells
29
Describe the cell tissue level
- begin to see animals here
- specific cells work together to have specific functions
30
at what stage of organization do we begin to see animals?
- cellular tissue level
31
Describe the tissue level
- true tissues secrete an extracellular matrix
- derived from embryonic germ layer
- highly coordinated unit
32
Describe the organ and organ system levels
- tissues work together to form an organ with a specialized function
- organ systems work together :Most complex (circulatory system, digestive system)
33
Review your knowledge of body symmetry terms!
- asymmetry
- radial: similar halves, like a pizza
- biracial: divisible into left and right in some planes
- bilateral: mirrored left and right sides when cut on a sagittal plane - anterior and posterior, dorsal and ventral
34
what does cephalization mean?
when nervous system concentrates to the anterior side of the body (head forms)
35
What are the two forms of body cavity organization? what do they mean for development?
- triploblastic: three germ layers - endoderm, mesoderm, ectoderm
- true body cavity can form
- diploblastic: only ectoderm and mesoderm - no true body cavity (eg; one mouth/anus hole, no gut)
36
What are two examples of diploblasts?
Cnetophores and cnidarians - sea anemones, jellyfish
37
What does gastrulation mean?
- the division of cells into the ectoderm and endoderm (sometimes mesoderm)
38
Describe the difference between diploblastic gastrulation and triploblastic gastrulation
- diploblastic: no mesoderm, cells divide into ectoderm and endoderm
- triploblastic: mesoderm forms in between!
39
What are the general development patterns of the ectoderm and endoderm?
- ectoderm becomes skin, endoderm forms gut
40
What are the 3 terms for the types of spaces between the ectoderm and the endoderm?
- Aceolomate: lacks ceoloum (space between) - mesoderm completely fills up space
- pseudoceolomate: mesoderm lines the ectoderm not the endoderm (gut) at all
- (Eu)coelomate: mesoderm lines ectoderm and endoderm- forms true pocket!
41
what is another word for the endoderm?
gut
42
What is unique about coelomates?
- mesoderm lines the endoderm and the ectoderm, allowing for a true coeloem (pocket) to form!
- higher level of organization within body plans, complex
43
True or False: the coelom is a synonym for gut
FALSE: Coelom is the space between the ectoderm and endoderm (pocket) formed by the mesoderm
- the gut is the endoderm, a tube within a tube
44
What are the two developmental traits that derive key body plan differences? What do they mean?
protostome and deuterostome
- protostome: mouth first
- deuterostome: mouth second
45
Describe the unique processes in protostome formation?
- spiral cleavage
- mosaic embryo (can't 'pull' a cell out ; leads to arrested development)
- blastopore becomes mouth, anus forms second
- coelom forms by splitting (just arrives!)
46
Describe the unique processes in deuterostome formation
- radial cleavage
- regulative embryo (can develop from one blastomere)
- blastopore becomes anus, then mouth
- coelom forms through out pocketing
47
What is true segmentation?
partitioning of the body parts into distinct sections
48
What are the 4 big basal groups?
1. porifera
2. radiata
3. placozoa
4. bilateral
49
Describe the phylum Porifera
- porifera: bore bearing
- sessile (sit at bottom) filter feeders
- body is efficient aquatic filter
- use choanocytes to move water
50
Are all porifera marine?
- most marine, some live in brackish water, some are freshwater
51
Describe the aquiferous system of porifera
- no mouth or anus
- oscia: incurrent pores, brings water in
- oscula: excurrent pores, brings water out
- space in between is called spongocoel
52
what are the two main cells in the phylum porifera?
- choanocytes and archaocytes
53
What are choanocytes?
- flagellated collar cells
- used for water currents and feeding
- powerhouse
54
What are archaocytes?
- Totipotent: can give rise to many kinds of cells
- exist in the mesohyl
- can become cells that: phagocytocize, make spicules, sponging, collagen, reproduction
55
where would one find a archaocyte?
- in the mesohyl of the song (phylum porifera)
56
What allows sponges to reaggregate?
- the archaocytes are totipotent and therefore can regenerate themselves
57
What are the three kinds of canal systems?
- asconoiod
- syconoid
- leuconoid
NOTE: canal system is like the pore that water flows through in the aquiferous system
58
What does asconoiod mean?
--> choanocyte-lined spongocoel
--> only found in class calcarea
59
What does syconoid mean
choanocyte lined canals
- folded inner alter creates canals
- only seen in class calcaerea
60
what does leuconoid mean
- choanocyte lined chamber
- increased in size
- no spongocoel (just osculum)
61
How do sponges stay upright?
- collage fibres in all sponges
- some sponges have specific collagen fibres called spongin
- spicules: calcium carbonate, silica
- unique to different classes; taxonomic fingerprint
- deters predators
62
what are the 4 kinds of relevant porifera? What do they all have in common?
Homoscleromoropha: skeleton absent
Calcarea: calcium carbonate spicules
- Demospongiae: spicules, spongin often present
- Hexactinellida:
- all have internal system of pores and canals
63
How do sponges feed?
- intracellular digestion
- phagocytosis: current brings in particles, archaeocytes (totipotent) engulf
63
Describe carnivorous sponges
- no choanocytes!
- hooks snare prey
137 spp
64
how do sponges reproduce?
- both sexually and asexually
- sexually: sperm from choanocytes released into water and taken in by another sponge whose archaocytes release oocytes (eggs)
- asexual: budding/fragmentation, or dormant gemmules (protected internal buds)
65
Why are sponges important to humans?
- first non food item to be (over) harvested (since they are filter feeders, coral reef providers, symbiotic relationships, this is harmful)
- pharmaceutical importance: have cancer curing compounds (due to long term existence / evolution)
- industry and technology
66
Describe the phylum placazoa
"flat animal"
- simple tissue
- asymmetrical symmetry
- 2 cell layers thicks, simplest body plan for all animals
- neither diploblast or triploblast (No ECM)
67
Describe the animal architecture of placazoa
- cell tissue
- asymmetrical
- development stops at blastula
- no body cavity
- no segmentation
68
What are the key transitions that occur between the phylum placazoa and the phylum cnidaria?
- true tissue develops
- radial symmetry
69
what species are found in the phylum cnidaria? How many species are there?
- sea anemones, coral, jellyfish
- ~10,000 aquatic species
70
What are the two main body forms in cnidaria?
- polyp (anemone) and medusa (jellyfish, eg)
71
Describe the polyp form of the phylum cnidaria
- polyp is mostly sessile
- coronal or solitary forms
- ie: anemone form
72
Describe the medusa form of cnidaria
- ie jellyfish form
- swimming around
73
What is the symmetry of cnidaria? What does this mean for their senses? what are their mouth parts called?
- radial (like a pizza)
- mouth side is oral, non mouth side is aboral
- can sense "all around" (no head)
74
True or False: cnidaria has a head
False
75
What kind of development does cnidaria have?
- cnidaria is diploblastic!
- has an ectoderm and an endoderm
76
How many tissues does the cnidaria have? Describe them please
- Cnidaria is a 'diploblast with 3 layers'
- ectoderm - develops into epidermis
- endoderm - develops in gastrodermis
- mesogela: a non-living 'jelly'
77
what kind of cavity foes a cnidaria have?
gastrovascular cavity: lined by the endoderm
- NOT a true body cavity (because they are diploblasts!!)
78
Describe the nerve and muscle cells of cnidarians?
- they have the ability to move
- epitheliomuscular cells
- nerve cells (one/two way synapses)
- nerve net: no true brain but has some control
79
What are cnidocytes? what parts are associated?
- found in phylum cnidaria
- called "nettle animal's cells"
- cnidocyte: the cell
- cnidae: capsules within the cell
- nematocyst: harpoon like paralyze prey with venom
- cnidocil: hair like trigger
80
What is commonly known as "nettle animals" cells?
Cnidocytes!
81
What is a cnidocil? How does it work?
- cnidocil is a hair like trigger that allows the nematocyst to fire its venom
- one time fire that uses hydrostatic pressure increase to trigger release
82
What part of the jellyfish has the most nematocysts?
- tentacles are covered in nematocysts, whereas the bell generally has none (why you can hold a jelly upside down)
83
How do cnidarians reproduce?
- sexually and asexually
- alternation of generations
- polyp reproduces asexually to produce the medusa form, medusa reproduces sexually (meiosis) to form the gametes which fuse to a planula larva - planula settles to form polyp
84
Describe polyp polymorphism
Clone buds ( zooids) in a single animal (ie: colony)
- types of zooid clones:
gastrozooids, gonozooids, dactylozooids
85
Describe the organization, symmetry, cavity, development, and segmentation of phylum cnidaria?
organisation: true tissue (diploblast!)
Symmetry: radial
Cavity: no true body cavity (gastrovascular cavity)
Development: diploblastic
Segmentation: no
86
What are the 5 classes of cnidaria?
- anthozoa (only polyp)
- staurozoa (only polyp)
- scyphozoa
- hydrozoa (only polyp)
- cubozoa
87
What are Anthozoa?
- polyp only "flower animal"
- anemones and corals
- tubular body and pharynx, large gastrovascular cavity
88
Describe the body of the class anthozoa?
- large gastrovascular cavity (think anemone)
- tubular body and pharynx
89
What are the two subclasses of anthozoa?
- hexacorillia:
- 6 axes of symmetry (eg; anemones, some corals)
Octorallia:
- 8 part symmetry
- proteinaceous, fleshy bodies
- mostly colonial
90
Why are anthozoa important to ecology
Coral reefs in general: 25% marine life, deep sea ecosystems, biodiversity hot spot, habitat
91
Describe the symbiotic relationship with zooxanthallae?
- anthozoa and zooxanthellae have a mutualistic endosymbiotic relationship
- zooks provide 90% of food for coral (O2 and sugars) and coral provides CO2, protection, wastes in return
92
What is the process called when zooxanthellae are expelled from coral?
Coral bleaching
93
What are some examples of mutualism with anemones?
fish (eg; clownfish) and crabs
94
Describe class staurozoa
- of the phylum cnidaria
- does NOT have a medusa form
- 8 extensions with adhesive pads ending in tentacle clusters
- creeping planula larva
- bod with white spots with nematocysts to defend gonads
95
Describe the class Scyphozoa
of the phylum cnidaria
- true jellies
- small or big
- dioecious
- large oral lobes extend from mouth
96
What are the 3 steps of reproduction for the class Scyphozoa?
- scyphistoma
2. strobila: long stack
3. Ephyra: separate stack and develop into large medusa form
97
Describe the class cubozoa
- square shaped bells (tentacles at the corners)
- rhopalia: eyes (some image forming)
- fatal sting
98
Describe class Hydrozoa
- of the phylum cnidaria
- disparate groups: many look very different
- includes the only freshwater cnidarians
- no medusa form (polyp only)
- most are colonial and exhibit polymorphism
99
What are siphonophores?
refers to the colonies of hydrozoans that form
100
What are ctenophores?
- phylum in basal group radiata
- comb jellies, eg (have 8 comb rows with paddle like ctenes) for swimming
- biradial symmetry
- exclusively marine!
- colloblasts cells
101
What are ctenes?
- ciliary / comb plates for swimming
- swim mouth forward using waves of beating cilia
102
How do cnetophora swim? what direction do they swim?
Swim using ctenes (plates covered in cilia)
- swim mouth forward using beating motion
103
Why are ctenophores colourful?
Most are not! most are transparent/colourless especially near the surface
- Some refract light off of the ctenes (rainbow)
- Some are bioluminescent (the highest % of luminescent) - usually blue/green using proteins in photocyte cells
104
How do ctenophores create light?
most don't but some are bioluminescent
- mostly green/blue, using proteins in photocyte cells
105
What are the different forms of predation in Ctenophora?
- most have 2 retractable tentacles with colloblasts (swipe cross mouth to eat)
- some use muscular mouth lobes to engulf prey
- some use cilia on lobes to draw prey / water in mouth
106
Do Ctenophora have nematocysts? Explain
No they do not but some can engulf and carry undischarged nematocysts of medusa cnidaria in a process called kleptocnidism
107
What are the body forms of Ctenophora?
- tentaculate: free swimming
- lobate: free swimming
- thimble shaped: free swimming
- Ribbon: free swimming (Venus girdle)
- creeping sole (epibenthic, sessile)
108
What is the largest animal to swim using cilia?
Phylum cnetophora, specifically the Venus girdle
109
Describe the nervous system of the ctenophores
- nerve net similar to cnidarians : nerve plexus concentrated under each comb plate
- statocysts: sense organ on aboral pole
110
What is the statocyst?
- in ctenophores, a sense organ on aboral pole
- with a statolith
- used for equilibrium / balance
111
How do ctenophores reproduce?
Asexually: regeneration of any lost part
Sexual: most monoecious, gametes shed into water via mouth = free swimming larvae
- some undergo internal fertilisation and brood their eggs
112
Describe the anatomy of the Ctenophora
Tissue
Biradial
Diploblast
no cavity, no segmentation
113
What defines bilateria?
- active, directional movement
- protostomia and deuterostomia
114
How does cephalization impact bilaterian development?
- sense organs at anterior end to sense environment head first
- moving in one direction
forward movement gives anterior and posterior
- mouth in head region - anus wastes left behind
115
Describe the makeup of the bilaterian groups
- xenaacoelomorpha: a basal sister group, still bilateral but NOT protostome or deuterostome
- protostome + deuterostomes = nephrozoa
- inc. Platyhelminthes
116
What is the phylum xenaacoelomorpha?
- new phylum, SISTER BASAL GROUP of the nephrozoa
- includes xenoturbella and acoelomorpha
- bilateral, triploblastic, aceoleomates
- unlike other bilaterians: lack anus, nephridia, circulatory system
- simple marine / brackish worms
117
Describe the group makeup of the bilateria
Bilateral are composed of nephrozoa and the xenaceolomorphs (sister basal group)
Nephrozoa: protostomes and deuterostomes
118
Where, in the groups, are Platyhelminthes located
in bilateral --> protostome --> lophotrochozoa (Platyhelminthes)
119
What are lophotrocozoa?
in the protostomes, some groups have trochophore larval groups and lophophore feeding structures
120
What are the Platyhelminthes?
- flatworm
- acoelomate, bilateral, tribloblasts, vermiform (worm like body)
- most parasitic
- no anus; intestines but no anus
- flame cells: excretion and osmoregulation
- developed reproduction; hermaphrodites
- four classes, phylogeny under debate
121
Describe the organization, symmetry and development of Platyhelminthes
- bilateral and dorso ventrally flattened
- tribloblastic and acoelomate body plan
- organs
122
What are flame cells?
in platyhelminthes; the earliest excretory system
- filters fluids from the body, removes metabolic waste
- controls osmotic pressure: retains important ions
- flame cells + tube cells = protonephridia
123
What are protonephridia
- the unit that flame cells and tube cells form together; found in the platyheliminthes
124
Describe the phylogeny of Platyhelminthes
- parasitic and non parasitic groups
- the non parasitic group is NOT a monophyletic group, they are paraphyletic
- the parasitic group is a clade
125
Describe the non parasitic groups in Platyhelminthes
- "turbellarians" - not a real clade
- textbook flatworm
- mostly free living; marine, freshwater, damp (terrestrial)
- small to large
- swim/glide with muscles, cilia, slime
126
Describe the skin and muscle of turbellarians
- ciliated epidermis
- epidermis contains rhabdites
- attach and detach system: dual gland adhesive organs
127
How do the turbellarians attach and detach?
with dual gland adhesive organs
128
Describe feeding the turbellarians
- muscular pharynx in ventral centre of body (mouth in middle)
- intestines can be simple or branched
- extracellular and intracellular digestion
- scavengers, predators
129
Describe the nervous system of the turbellarians
- cephalization
- diffuse nerve plexus and ladder like pattern
- auricles: ear like lobes packed with chemoreceptive and tactile cells
- statocysts, rheoreceptros (currents) and ocelli (eye spots)
130
What are auricles? Where can they be found?
In turbellarians: ear like lobes packed with chemoreceptors and tactile cells
131
How do turbellarians reproduce?
- asexually; fission, reproduction
- sexually: hermaphrodites (monecious), internal fertilisation with copulation
132
What group sees the penis fighting flatworms?
- the turbellarians of the Platyhelminthes: don't want the burden of bearing eggs, try to fertilize the other
133
Describe the parasitic clade of the Platyhelminthes
- monophyletic ( a real clade)
- called Neodermata
134
Describe the skin of the Neodermata
- syncytial, no ciliated epidermis
- unites parasitic group into neodermata
135
Describe the digestive system of neodermata
- lacking in some groups (absorption)
136
describe reproduction and the nervous system in Neodermata
- minimal cephalization
- reproduction: different among the classes
137
What are the four "classes" of platyheminthes?
- turbellarians, trematoda, monogenea, Cestoda
138
Describe the class cohort Trematoda
- the parasitic flukes
- endoparasitic
- adaptations for parasitism: enzymes, hooks, penetration, cyst forms
- most have complex life system: digenea = 2 hosts
139
Which subclass requires 2 hosts to complete its life cycle
Neodermata: Class cohort Trematoda: the subclass digenea requires two hosts
140
Describe the life cycle of Digenea Flukes
1. intermediate host: first host, amplification (asexual)
2. Definitve host: final host (sexual)
- think human --> eggs eaten by snail --> amplified eaten by fish --> into human
141
What are some common digenean flukes?
Liver fluke: undercooked/raw fish
blood fluke:
- schistosomiasis
- enters human skin and enters blood vessels and intestines
- anemia and indirect symptoms
- swimmers itch
142
Describe the class cohort Monogenea
One host only!
- ecotoparasitic
- on skin/gills of fish
attachment called opisthaptor
- simple life cycle: eggs --> ciliated larvae --> adult
143
Describe the class cohort Cestoda
→ The tapeworms
→ long, flat bodies with key features:
Endoparasitic (hang onto intestines)
Scolex (attachment to host)
Strobila (main body) of proglottids (reproductive units)
No digestive system (no mouth, only attachment)
Microtriches
144
What is the main body of the Cestoda called?
- main body: strobila
- NOT true segmentation (individual units can be shed)
- reproductive factories
- youngest at head, mature (gravid) posterior
- fertilisation from same or different strobila
- eggs out of the uterine pore
145
How do humans get infected by Cestoda?
- protected larvae shed from colon (out faces) and ingested by an intermediate host (eg; cow)
- larvae form cysts in the muscle
- undercooked meat consumed by human, living cysticercus eaten by definitive host
146
What is the pork tapeworm? Is it lethal?
- an example of Cestoda ingestion
- pork tapeworm :
- mostly harmless if ingested cysticercus (via undercooked meat): anemia, discomfort, diarrhea
- BUT if ingested fertilized egg (eg; contaminated faces) meant for intermediate host can be lethal
147
What is cysticercus form?
- the larval form of Cestoda (of the parasitic Platyhelminthes
- not lethal if ingested by human but if the fertilised egg meant for intermediate host is ingested it can be lethal
148
Describe the organizations of the Platyhelminthes?
- organisations: organs
- bilateral symmetry
- acoelomate
- no segmentation
- tribloblast
149
What are the Great Lophotrocozoans?
- trochozoans : the annelids
- AKA ring worms / bristle worms
- marine, freshwater, damp terrestrial
- deposit feeders, predators, suspension feeders, blood feeders
- closed circulatory system and centralized nervous system
150
What is the key transition found in the Annelids?
- true segmentation / metamerism
- body composed of serially related unit separated by septa:
- each unit contains components of most organ systems - derived form mesoderm
- coelom plays a large role
151
How do annelids perform locomotion?
- the coelom separated the body tissues and eventually body parts
- coelom is filled with fluid and is a hydrostatic skeleton
- contraction of the circular muscles: elongation and lengthening
- contraction of the longitudinal muscles: shorten and expand
- alternating these muscle movements leads to movement (peristalsis)
152
What allows for efficient burrowing in the annelids?
- coelom is fluid filled and allows for peristalsis
153
What are 2 defining features of the annelids?
- setae/chaetae
- parapodia
154
What are setae?
- chitinous epidermal bristles
- helps in burrowing, tubes, locomotion
- in the annelids (not leeches)
155
What are parapodia?
- paddle like feet
- used in swimming, crawling, sensory, respiration, modified gills
- not seen in many groups
156
What are the three historical annelid divisions?
- polychaete, oligochaetes, hirudineans
157
Describe the clade Errantia
- motile polychaete body plan: many long hairs
- mostly marine
- well developed sense organs and cephalization
- external fertilisation with trochophore larvae
- eg; sand strike worm
158
What are the clades found in the annelids
- Errantia and Sedentaria
159
Describe the clade sedentaria
- sedentary tube dwelling polychetes - beard worms, spoon worms, oligocheates and leeches
- modified heads for filter feeding/particle feeding
or reduced heads for deposit feeding
160
Describe the sedentaria "polychaetes"
- tube dwellers
- cilia mucus and food grooves on tentacles for food capture
- reduced parapodia: respiration or separates gills
- reduced setae: anchor into burrows and tubes
161
Describe the family siboglinidae
-Annalid, of the class sedentaria
- beard worms discovered in 20th centrury
- secrete long chitinous tube dwellers
- no mouth or digestive system - absorption via/depend on bacteria that use H2S
- found in hydrothermal vents
162
Describe the family Echiuridae
- spoon worms
of the class sedentaria
- flattened, extendible proboscic
- unsegmented
- homologous annelid state
163
Describe the order Clitella
- synapomorphy: clitellum (reproductive structures)
- oligochaete body plan
- no parapodia, setae reduced/lost
- hermaphroditic
- all have direct development (no trochophore larvae)
164
What are oligochetes
subclass of the family clitella
- freshwater, marine, terrestrial
- earthworms
- developed circulatory, digestive, excretory systems (nephridia)
- ecologically important
165
Do carnivorous sponges have choanocytes?
nope, they have microscopic hooks to snare prey
166
What does 'Mollusca' mean?
Soft
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Which phylum is the most diverse?
phylum mollusc - 90k species -highly diverse and disparate
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Why are molluscs important to humans?
food, pearls/shells, bioindicators, pests, biotechnological/medical importance
169
How is climate change impacting molluscs?
Ocean acidification is making shells weaker
170
What is the archimollusc?
HAM: Hypothetical Ancestral Mollusc
- common ancestor of all of the molluscs
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What makes a mollusc?
1. Head foot
2. visceral mass
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Describe the head foot
Head: sense organs + feeding
- radula: chitnous ribbon of teeth (not in bivalves), odontophore cartilage holds teeth
- foot:locomotion, attachment, ventral side
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What is odontophore cartilage?
Holds the teeth of the radula
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Describe visceral mass
- includes internal organs (digestion, excretory, reproductive, respiratory)
and mantles and mantle cavity
175
What is the mantle and mantle cavity?
Mantle.= the skin - can have muscles, chemoreceptors, etc
- makes the shell!
Mantle cavity: open to the world, for excretion (metabolic and digestive waste)
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What forms the shell?
the outer layer of the mantle secretes the shell
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What are the 3 layers that form a shell?
1) Periostracum: outer organic layer
- resistent protein concholion
2) prismatic layer: CaCO3 stocks
3) nacre: mother of pearl - continuously thickens, CaCO3 protein sheets
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What are pearls?
layers of nacre overlapping invading particles
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what are the basic internal characteristics of the Mollusca?
- bilateral coelomates (reduced coeloms)
- mantle/cavity for respiration (gills, lungs, diffusion)
- most have open circulatory systems
- complex digestive system
- varied nervous system
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Describe the reproductive system of Mollusca
almost never asexual
- dioecious or monoecious
- trochophore larvae in most
veliger larvae common (aquatic bivalves and gastropods)
- some have direct development
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Which classes have veliger larvae?
- bivalves and gastropods
182
Describe the organization of Mollusca
- coelomate
- triploblastic
- bilateral symmetry
- no segmentation
- organs
183
What are the 8 classes of molluscs
Aplacophorans: class caudofoveata and solenogastres
Class polyplacophora
Class monoplacophora
Class gastropoda
Class bivalvia
Class Scaphopoda
Class Cephalopoda
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What are the Aplacophorans
- classes caudofoveata and solenogastries
- AKA spicule worms
- wormlike, shell less
- calcareous spicules
- reduced head/no foot
- burrowed; detrital consumers, marine
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Describe the Polyplacaphorans
- "Many plates" - 8 moveable plates
- mantle girdle around outside
- some serial repetition: ctenidia (gills) on lateral grooves on the mantle cavity
- marine intertidal grazers on hard bottom
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Describe the monoplacaphorans
- "one plate" -
- large foot
- shell like round shell
- serial repetitionL gills, nerves, gonads, nephridia
- deep sea grazers on hard ground
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Describe the class Gastropoda
eg; snails and nudibranchs
- highly diverse, most diverse of the Mollusca
- 'stomach + foot'
- coiled shell, dome shell, no shell - some have a protective operculum
- widest range of habitats (all)
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What is the snails 'door' called?
a protective operculum
189
What are the 3 functional groups of gastropods?
1. Prosobranchia: gills in front of heart - most marine snails
2. opistobranchia
- gills behind heart; most marine shell less forms (cerata)
3. Pulmonata: no gills, mantle cavity develops lungs
- most land and FW snails/slugs
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what are torsion and coiling? Which happens first?
torsion: 180 of the mantel and mantle cavity
coiling: coiling of the shell
- both occur ~same time during development (veliger) but coiling occurs first
191
Describe the feeding habits of gastropoda
- diverse but all adaptations of the radula
- piercing, drilling, scraping
- herbivore, scavenger, carnivore; some use photosynthetic endosymbionts (sheep slug)
192
How do gastropods reproduce?
- simultaneous hermaphrodites
- love dart = boost sperm production before mating
- eversible gonopores - simultaneous sperm transfer
193
Describe the class bivalvia
- clams
- two valve shells
- NO HEAD, NO RADULA
- laterally compressed body: hinge on the dorsal side, gapes open ventrally
adductor muscles attach the two side
- marine/FW
194
what attaches the bi valve in clams?
the adductor muscles!
195
How do bivalves breathe?
- they have 1 set of ctenidia (gills) for respiration and particle intake
196
How do bivalves move?
- clam uses foot (burrowing)
- adductor muscles to swim (scallops)
- some sessile (byssal threads, cemented)
197
Describe the class Scaphopoda
- tusk shells/tooth shells
- shell open at both ends
- a lot of diffusion in mantle cavity: no heart, no gills
- tentacular foot (captacula) for burrowing/food capture (foraminifer)
- marine/benthic burrowers
198
Describe the class Cephalopoda
- "head foot"
- predators (beak like jaws)
- arms, tentacles, siphons
- marine only
199
Describe the basic body of the cephalopods
- 8 arms (squids/cuttelfish have 2 tentacles)
- closed circulatory system
- incredible nervous system: large vision centre in brain, large lens eyes, intelligent/likely sentient, innervation of arms
200
DO cephalopods have shells?
nautiloids; large shell
Cuttle fish : internal cuttle bone
Squid: ink pen
Octopus: none
201
How do cephalopods move?
Arms, jet propulsion, fins
202
How do cephalopods camouflage and ink?
- camouflage using 4 types of chromatophores
- ink: melanin (and some mucus) from anus
203
How do cephalopods reproduce?
- diocieous
- mating rituals
- direct development
- semelparous
204
Describe phylum Nemertea
- ribbon or proboscis worms
-long, fragile
- known for their proboscis that extends from the rhynocoel cavity
- coelomate, mostly carnivorous, unsegmented
- produce neurotoxins, pharmaceutical chemicals, pesticides
205
Why are small lophotrocozoans so important?
Form the base of the food chain
206
Describe the phylum Rotifera
- pseudocoelomate
- external segmentation only, not internal
- have rotating crown of cilia called corona
- the pumping pharynx = mastax
- many species without males (parthenogenetic diploid egg)
- others where the amictic egg = females and unfertilized mictic (haploid) eggs = male
- Dormant fertilized eggs can withstand desiccation for months
207
Why is it that the first species to show up after drought might be Rotifera?
- because their fertilized eggs can withstand desiccation for months
208
What are the different rotifer body styles?
- globular, colonial, swimmers/creepers, sessile = vase like
209
Describe the subclass acanthocephela?
- spine head
- retractable spikey proboscis
- all parasitic vertebrate intestines (eg fish)
- crustaceans are the intermediate host
- absorb nutrients through epidermis, NO DIGESTIVE TRACT
210
What are the "lophophorates"
- lophophore: crown of cilia covered tentacles
- extension of the coelom
- feeding/respiration
- U shaped
- mouth inside, anus outside
211
Which phyla are lophophorates
- Ectoporcota, brachiopoda, phoronidia
212
Describe the phylum Ectoprocta
AKA Bryozoa
- rich fossil record since to Ordocivian period
- most colonial (zooids) in zoecium (onblong calcareous chamber)
- invasive, fouling
- medial compounds via bacterial endosymbionts
213
Describe the phylum Brachiopoda
- lamp shades
- ancient
- articulate and inarticulata
- two calcareous shells secreted by a 'mantle' = ventral and dorsal
- attached with a pedicel
- bottom dwelling, shallow marine
- adults non segmented but larva show some repetition of ecto/mesoderm tissue
214
Describe the phylum phoronida
- ~10 spp
- wormlike, unsegmented
- leathery chitonous tube
- unique actinotroch larvae
- benthic substrate
