BIOL V03 Lecture: Invertebrates (Campbell10: Ch 33)
“life without a backbone”: just the phyla in the text
©
2014 copyright Marta D. de Jesus
Note: we are not covering all animal phyla & animal phylogeny is still being actively
researched; some of this may change with time... (at least 2 newly discovered phyla within
the last 10 years)
I. P? Porifera = sponges (pore animals) ~5500 spp.
A. body plan:
1. symmetry
2. diploblastic development
a. outer epidermis
1) epidermal cells
2) porocytes
ostia
b. middle mesohyl
1) amoebocytes
spicules
2) skeletal materials
c. inner layer
choanocytes
3. osculum
B. reproduction
1. sexual
a. sexes
b. gametes from
c. use cross-fertilization
2. asexual
gemmules
C. ecology: mostly marine
1. mostly filter/suspension feeders,
sessile
2. others
D. history
1. oldest animals?
2. monophyletic group: probably not
The Shape of Life Video clips: traveling through a sponge (feeding), spicules, waterpumping
II. “Coelenterates” - old name no longer used
A. shared characteristics
1. have tissues
2. radial symmetry
3. respiration & excretion
4. diploblastic development
B. P: Cnidaria
1. 2 basic body plans
a. polyp vs. medusa
1) gastrovascular cavity
2) mouth/anus – oral surface
other surface: aboral
3) tentacles
4) nerve net
2. tissues
a. epidermis
mesoglea
b. gastrodermis
c. some have hard skeletons
3. hunters using cnidocytes
a. nematocyst
4. 2 clades with 4 classes
a. Cl: Medusazoans
C: Hydrozoa
C: Scyphozoa
C: Cubozoa
b. Cl & C: Anthozoa
5. habitat
6. reproduction
a. asexual
b. sexual
dioecious
The Shape of Life Video clips: body plan, polyp vs. medusa, nematocysts on feeding
tentacles, fighting tentacles
C. P: Ctenophora
1. habitat
2. size range
3. some have retractable feeding tentacles
4. 8 rows of comb-like plates of fused cilia
5. superficially like Cnidarians
6. colloblasts
7. some bioluminescent
8. not well known
II. Minor phyla
A. Placozoans
habitat
body
B. Acoel flatworm
physically resemble flatworms
but
III. Bilateria
A. shared characteristics
1. bilateral symmetry & start of cephalization
2. triploblastic development
3. have organs
IV. Lophotrochozoans: allied by DNA
A. lophophore
B. trochophore larva
C. P: Platyhelminthes
1. in general
a. movement by
b. acoelomate
c. digestive system
1) pharynx
2) gastrovascular cavity
d. nervous sysem
1) ventral nerve cords connected by horizontal nerves
2) ganglia in head
sensory organs
e. osmotic regulation & waste removal:
protonephridia
f. reproduce
sexually
asexually
g. ecology: live in damp terrestrial & water
2. Major Classes
a. C: Turbellaria
eg: planaria
c. C: Trematoda
eg: Schistosoma
d. C: Cestoda
scolex
proglottids
eg: Taenia
The Shape of Life Video clips: body plan, predatory behavior
D. P: Rotifera
1. mostly fw
2. very small
a. hydrostatic skeleton
some have lorica
b. complete animals with organ systems
3. reproduce
a. some only asexually parthenogenesis
b. some can reproduce sexually
4. cryptobiotic
E. Lophophorates
1. P: Brachiopoda
marine
resemble bivalves but not
2. P: Ectoprocta = Bryozoa
marine & fw
small, colonial
reproduce asexually & sexually
F. P: Mollusca = mollusks
1. basic body plans
a. ventral foot
b. visceral mass
c. unique
1) mantle
2) radula
d. open circulatory systems (except cephalo’s)
2. most are unisexual; but many snails are hermaphrodites
3. major classes (T33.3)
a. C: Polyplacophora
b. C: Gastropoda
1) largest group
2) habitat
3) torsion of body
c. C: Bivalvia
1) habitat
2) gills used feeding
3) no distinct head
d. C: Cephalopoda
1) habitat
2) predators
3) advantages: brain, siphon, eyes, body coloring
4) large size range
5) mostly no external shells
6) closed circulatory system
The Shape of Life Video clips: body plans
G. P: Annelida
1. size range
2. habitat
3. basic body plans
a. segmentation
setae
b. closed circulatory system
c. metanephridia
4. 2 major clades
a. Cl: Errantians: most of the former Polychaete
1) habitat
2) many setae & parapodia
3) well-developed head & sense organs & metal-rich teeth
b. Cl: Sedentarians
1) earthworms & relatives: few bristles [33.25]
habitat
some important to soil ecosystems
all hermaphroditic
2) tubeworms
3) leeches
habitat
some predatory, some parasitic
used medicinally
The Shape of Life Video clip: body plan
V. Minor Lophotrochs
A. P: Acanthocephalans
curved hooks on head
B. P: Cycliophora (1 sp.)
1. relatively new phylum (1995)
2. small
3. strange life style on lobster “lips”
C. P: Nemertea
1. habitat
2. predators; often colorful
3. size range
VI. Ecdysozoans
A. usually have external exoskeletons/cuticle & must molt (ecdysis) to grow
B. P: Nematoda
1. may be single most abundant kind of animal (individuals)
2. habitats
3. lifestyles
a. decomposers/detrivores
b. parasite
eg: Ascaris, hookworms, Trichinella, pinworms, filiarsis
c. predatory (with teeth)
4. anatomy
a. size range
b. pseudocoelom
c. only longitudinal muscles
d. no specific circ system structures
e. usually reproduce sexually
C. P: Arthropoda
1. found everywhere
2. keys to success
a. true coelom & segmentation
b. jointed appendages
c. exoskeleton (cuticle of chitin)
3. open circ. system
4. 2 sexes
5. major groups (T33.5)
a. Cl: Trilobitomorpha
b. Cl: Chelicerata
1) 6 sets of appendages
2) Horseshoe crabs
3) Arachnids
- mostly terrestrial & carnivorous
- body plan
cephalothorax & abdomen
- use book lungs or gills
c. Cl: Myriapoda
1) Chilopoda
carnivores
2) Diplopoda
herbivores
d. Cl: Pancrustaceans: insects, crustaceans, & others
1) Crustaceans
habitat
body plan
head, thorax, & abdomen
biramous = branched appendages
2 pair of antennae
pair of mandibles
2 pairs of maxilla
3 pairs of maxillipeds
1 pair of chelipeds (pincers)
4 pairs of walking legs
5 pairs of swimmerets
1 pair of uropods
compound eyes
gills
2) Insects
the most successful group of animals
habitat
3 part body:
head, thorax & abdomen
6 pairs of walking legs
unbranched appendages (1 pair of antennae,
mandibles, maxillae)
compound eyes
tracheae
Malpighian tubules
incomplete metamorphosis vs. complete
The Shape of Life Video clip: body plan
VII. Minor Ecdysozoans
A. P: Loricifera
1. deep sea marine
2. have a corset (lorica)
3. at least 1 sp. anaerobic
B. P: Priapula
1. marine
2. size range
3. burrow in mud
4. protostome in most respects but mouth forms 2nd
C. P: Tardigrada
1. small
2. habitat
2. walk
3. survivalists
D. P: Onychophora
1. habitat
2. between annelids & arthropods?
3. spitters
VIII. Deuterostomes
A. characteristics
B. P: Echinodermata
1. general characteristics
a. habitat
b. adults pentaradial symmetry/larvae bilaterally symmetric
c. calcium endoskeleton
d. unique water-vascular system
2. classes
a. C: Crinoidea
oldest group
filter feeders
b. C: Asteroidea
most familiar group
5-20 arms usually
mostly carnivores
can reproduce asexually
recently added: sea daisies
c. C: Ophiuroidea
why named
d. C: Echinoidea
NO arms
often herbivorous
e. C: Holothuroidea
elongated bodies
The Shape of Life Video clips: body plan, starfish behavior
E. P: Hemichordata
1. head resembles acorn
2. “half-chordates”
F. P: Chordata (next chapter)
Useful websites:
Marine Life of So. Calif
http://www.cyberphyla.com
An on-line animal museum
http://www-biol.paisley.ac.uk/courses/Tatner/biomedia/home/
UCMP at Berkeley
http://www.ucmp.berkeley.edu/