05/06/2004 I still have to update the notes
Test tips: familiarize yourself with all the material you have observed in lab especially those that you have figures and text for (on this page or your lab text). know the material (anterior-posterior, medial-lateral, proximal distal, dorsal-ventral positions and orientations). know the different dermal bones of the skull, lower jaw; the bones of the girdles and limbs and their processes, bones of the hands and feet of the cat.
to print the figures etc, save the file and then print
Follow Dr. Campbell’s notes
you should be able to identify organs/structures of different parts and different groups of animals. watch out for characters that are lost/reduced or exaggerated due to specialization
classification and characters of chordates (Kingdom, phylum...)
terms - planes of symmetry and direction...
shared and unique characters of each sub-phylum and shared characters with invertebrates :-
Chordata characters (gill slits; notochord; dorsal hollow nerve cord; tail behind posterior end of digestive tract)
characters of Vertebrates (bilateral symmetry; 2 pairs f jointed appendages/limbs; internal segmentation / metamerization; endoskeleton; distinct well developed brain; dorsal nerve cord; closed circulatory system with a ventral heart and median dorsal artery)
Hemichordates
enteropneusta, pterobranchia
Stomochord present but does not function like the notochord and their homology is uncertain.
'U' shape gill slits and pores present supported by 'm' shaped skeletal rods chordate feature
tongue bar in gill slits amphioxus character
hepatic-caeca may not be homologous with vertebrates
invertebrate character - dorsal and ventral nerve cord present; dorsal is not hollow
larva is like echinoderm
Cephalochordates
notochord present, acts as hydro-static skeleton
segmented body, though assymmetric, myomeres present, metamereic nerves present
anus to left of mid-ventral
gill slits divided unlike enteropneusts, tongue bar and skeletal rods are also similar to enteropneusts
endostyle function...
pre-oral ciliary organ of enteropneusts similar to wheel organ of cephalochordates
branchiostome pharynx similar to tunicate pharynx
Urochordate
notochord present in tadpole larva
neural tube present
no segmentation
Vertebral column of vertebrates
Vertebrae form at intersections of myotomes
types of tail in fishes
Types of vertebrae; Parts of vertebrae
Identifying vertebrae in isolation (anterior/posterior; Differentiation in the column)
Specialized / unique / lost characters of vertebrae of certain groups
Salamander Vertebrae - 5 poorly differentiated regions; 1 cervical (lack of processes = limited dorso-ventral head motion); all trunk vertebrae but last few have ribs; 1 sacral; sacral ribs attach to pelvic girdle; 2 to 4 caudo-sacrals (may or may not have ribs); last caudo-sacral has haemal arch - support cloaca; caudals have haemal arches.
Observe key characters of the frog, bird and reptiles
Frog Vertebrae - 1 cervical (lack of processes = limited dorso-ventral head motion); no tail; no haemal process; ribs present in primitive adult frogs; 1 sacral followed by long urostyle (composed of post-sacral vertebrae).
more cervical vertebrae result in greater flexibility of the neck. no centrum in the atlas, it has become the odontoid process. length of the centrum determines the neck length. vertebre-arterial canal or transverse foramen of the mammalian cervical is formed by the fusion of the bicipital cervical ribs to the transverse process and centrum. the vertebral artery passes through this foramen. the canal may be present in birds. this blood vessel is present in reptiles but does not pass through any canal.
Turtle (Reptile) Vertebrae - 8 cervical vertebrae are procoelous allowing great flexion.
Bird Vertebrae - specialized for flight; body vertebral column is inflexible; Atlas similar to mammals (no centrum) - may be independently derived; Cervical - heterocoelous for greater neck flexion; Synsacrum - fusion of last thoracic to first few caudals + pelvic girdle for weight bearing (this fusion reduces the need for many muscles, thus reducing weight for flight); pygostyle present (fusion of last few caudals).
Mammal vertebrae - 5 differentiated regions; usually 7 Cervical (Atlas and Axis; all but last perforated by vertebre-arterial canal); Thoracic (costal facets for rib articulation; tall neural spine; short centra; small pre and post zygapophyses; last few have reduced neural spine and transverse process, but more prominent zygapophyses with extra process called metapophysis); Lumbar (large and stout; large neural spine; anteriorly directed transverse process; prominent ancillary processes - meta and anapophysis); Sacrum (fused 3 in cat, 5 in man; articulate with ilia of pelvis; large lateral expansions; Caudal (all processes are diminished caudally; coccyx in man)
Skull
Chondrocranium (encases the brain; no roof; cartilaginous)
Dermatocranium (amphioxus, lamprey, fish, tetrapods),Dermal bones of skull roof and palate (1, 2, 3), and of lower jaw
Variation in skull between groups; types of skulls (Anapsid, Synapsid, Diapsid)
Splanchnocranium (visceral skeleton), Branchial arches number and their fate (amphioxus, lamprey, fish, tetrapods) homologies. the first visceral arch was the mandibular that required the support of hyoid arch (2nd arch) when it formed biting jaws. Thus the dorsal part of the mandibular (palatoquadrate) was in contact with the chondrocranium (connected by ligaments), supported by the dorsal of the hyoid arch posteriorly. the ventral or distal portion of the mandibular (Meckel's cartilage) became the functional lower jaw. this condition is referred to as the amphistylic jaw suspension. The condition where the palatoquadrate is supported by the hyoid arch only and from the chondrocranium by ligaments only is referred to as hyostylic suspension (occurs in sharks). The condition where the amphistylic palatoquadrate is instead fused to the chondrocranium, thus obviating the support of the hyoid arch is referred to as autostylic suspension. this resulted in the hyoid arch (its dorsal component only) being incorporated into the middle ear of mammals (columella / stapes), as they were already in a position conducting vibrations from the external environment to the inner ear (otic capsule, to which they were attached). The quadrate-articular (refer figure on homologies) jaw articulation is found in tetrapods except mammals. they form the incus and malleus of the middle ear respectively in mammals.
fate of the palatoquadrate, meckel's cartilage and hyoid (2nd branchial) arch in jaw suspension and in different tetrapods.
Types of teeth, dentition, which bones bear what teeth
shark skeleton; necturus skeleton; frog skeleton; turtle skeleton (2, lower jaw); bird skeleton; cat skull disarticulated; cat skull notes;
Pectoral girdles (fish, tetrapods) (follow lab text)
Amphibians - the girdle is not attached to the vertebral column; they have only 4 fingers.
Turtle - no sternum because of plastron; clavicle is absent - fused into the plastron; the girdle has a dorsal scapula, ventral coracoid and an acromion process (anterior projection from the scapula) = homologous to that of mammals.
Birds - interclavicle = wish bone; sternum has a strong keel (ventral) for attachment of flight muscles.
Mammals - no interclavicle or precoracoid; clavicle is missing sometimes; diferentparts of the scapula shown in your lab text are sites of muscle attachment.
Pelvic girdle
Elasmobranchs pelvis(fused pair of cartilaginous plate = pelvic girdle)
Primitive amphibian pelvis is of large bony plates; modern amphibian pelvis is derived; [ventral puboischiaic cartilaginous plate; posterior rounded ossification = ischia; ilium is dorsal articulating with sacral rib; femur fits in acetabulum (junction of pubic cartilage, ischium, ilium) like a ball-socket joint]
Reptile pelvis (little cartilage; flat; large foramen between pubis and ischium; large dorsal projecting ilium; pelvis is lost or greatly reduced in snakes)
Bird pelvis (continuous innominate bone by fusion of ilium ischium and pubis also fused with sacral = synsacrum; acetabulum is meeting point of the 3 bones; femur head fits into acetabulum, it descends directly ventral from the girdle; innominate bones are widely separated ventrally, probably for egg laying)
Mammal pelvis [fusion of the same 3 bones to form innominate hip bone; ilium dorsal and largest articulates with sacrum, ischium is dorsal and posterior to acetabulum (posterior end = rough curvature in cat - ischial tuberosities, meeting at the ischial symphisis); pubis is anteroventral of innominate; ischial and pubic symphyses are fibro cartilage; acetabulum is where the three bone meet and form a part of the acetabulum]
ribs and sternum
Sternum occurs only in tetrapods; cartilage in amphibians and reptiles; they serve to provide a base for the pectoral girdle, and ribs to brace and source of the ventral muscles of the fore limbs.
Tetrapods have double headed ribs (bicipital - dorsal tuberculum, and ventral capitulum). no skeletal cage of ribs in amphibians; ribs have proximal (to the vertebra) costal rib and distal sternal rib. latte may be cartilaginous.
salamanders have bicipital ribs, but frogs have only a single head on the ribs.
turtle have no cervical ribs. ribs of the trunk are fused with the costal plates. sacral ribs are short, not fused to the costal plate; instead they fuse with ilia of the pelvic girdle.
birds - 5 pairs of thoracic ribs, haing an uncinate process. posterior ribs fuse with synsacrum.
mammals - the costal ribs are cartilaginous.
Limbs and digits (know the different bones, shapes, position, points of attachment of bone/ ligament/ muscle)
tetrapod limb (Propodium, Epipodium, Mesopodium, Metapodium, Phalanges)
propodium - humerus / femur
epipodium - radius-ulna / tibia-fibula
mesopodium - carpus (wrist) / tarsus (ankle)
metapodium - metacarpus (palm) / metatarsus (sole)
phalanges - fingers / toes
fore limbs; hind limbs; bat wing
patella = sesamoid bone, (mineralized nodule developed in a tendon/ligament in a zone of stress)
references (including illustrations on this page):
Wake, M.H. (editor). 1979. Hyman's Comparative Anatomy (3rd edition). The University of Chicago Press.
Kent, G.C. and L. Miller. 1997. Comparative Anatomy of the Vertebrates (8th edition). Wm. C. Brown Publishers.
links :
