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Long Exam 1 Intro to Tetrapods
The study of the descriptive and functional morphology of vertebrates
Comparative anatomy
What do you call the study of evolution which shows the changes in structures of different animals across time?
Phylogeny
morphology:____________
anatomy:_______________
structural evolution; describing the structure as it is
Species are grouped together with how they are similar to each other
Cladogram
not all species of chordates would develop the structures as they get more mature. these are called what?
prochordata
Animal species with distinct head part with tripartite brain
Craniata
Jawless animals
Agnathan
Why are prochordates and chordates grouped in a single taxon?
because they possess these FIVE ELEMENTS in at least 1 point in their lifetime
Rod of living cells ventral to the CNS and dorsal to the alimentary canal
notochord
what will the notochord develop into in adulthood?
vertebral column
more complex, jointed skeleton that develops in most vertebrates
vertebral column
do adults retain the notochord?
no, this develops into the vertebral column since adults retain only remnants of the embryonic notochord
the part of the notochord near the head region will be incorporated into the ____________ while those in the rest of the body will eventually _____________
skull floor
surround the cartilaginous or bony vertebrae structures
what are the different fates of the notochord during adulthood?
protochordates: chief axial skeleton surrounded by notochord sheath
agnathans: chief axial skeleton + lateral neural cartilages
fishes and amphibians: Persists the length of the trunk and tail within the centrum of the vertebral column
reptiles, birds, and mammals (amniote): Disappears and becomes pulpy nucleus in mammal vertebrae
an animal whose embryo develops in an amnion and chorion and has an allantois; a mammal, bird, or reptile.
amniotes
What do you call the study of evolution which shows the changes in structures of different animals across time?
phylogeny
does the notochord develop into the CNS?
No
the dorsal hollow nerve cord of a chordate embryo develops from what?
a plate of ectoderm that rolls into a tube dorsal to the notochord through invagination
the action or process of being turned inside out or folded back on itself to form a cavity or pouch during gastrulation
invagination
this develops into the CNS— the brain and spinal cord
dorsal hollow nerve cord
the pharynx is common to what two phylum?
hemichordata and chordata
these are species that do not possess all 5 criteria to classify them as chordates
hemichordates
the pharynx can be perforated by what?
openings (stilts) to either the exterior or an atrium (reflecting common ancestry)
define the pharynx
Membranous digestive and respiratory organ located at the back of the mouth that serves as passageway of food and air
what does the pharynx develop into?
gills of fishes (permanent slits)
lungs for tetrapods (temporary slits)
skeleton and musculature of jaws
endocrine glands (Parafollicular cells and parathyroid glands)
middle ear cavity of tetrapods (Auditory and tympanic cavity )
initial cells of immune system during fetal life and shortly after (thymus)
what are the embryonic components of the pharynx?
pharyngeal arches
pharyngeal clefts
pharyngeal pouches
pharyngeal slits
pharyngeal arches are separated by grooves. of the groove is OUTSIDE the embryo, what is it called? what if it is INSIDE the embryo? what if it makes an OPENING?
cleft; pouch; slit
what do the arches develop into?
skeleton
muscles
nerves
blood vessels
how many pairs of arches develop in the cranio-caudal sequence?
6 pairs where development starts from the pharyngeal arch closest to the head (cranial) and proceed caudally to the tail
Indentations are present in both external and internal arches. describe each
external: clefts lined with ectoderm
internal: pouches lined with endoderm
what are the skeletal elements in the first pharyngeal arch?
meckel’s cartilage
malleus
incus
what are the muscles in the first pharyngeal arch?
muscles of mastication
anterior belly of digastricus
tensor tympani
tensor palati
what cranial nerve in the first pharyngeal arch?
trigeminal nerve (mandibular division)
what are the skeletal elements in the second pharyngeal arch?
stapes
styloid process
upper part of hyoid
what are the muscles in the second pharyngeal arch?
stapedius
stylohyoid
muscles of facial expression
posterior belly of digastricus
what is the cranial nerve in the second pharyngeal arch?
facial nerve
what is the skeletal elements in the third pharyngeal arch?
lower part of hyoid
what is the muscle in the third pharyngeal arch?
stylopharyngeus
what is the cranial nerve in the third pharyngeal arch?
glassopharyngeal nerve
what are the skeletal elements in the 4th-6th pharyngeal arches?
laryngeal cartilages
what are the muscles in the 4th-6th pharyngeal arches?
cricothroideus
pharyngeal constrictors
instrinsic laryngeal muscles
what is the cranial nerve in the 4th-6th pharyngeal arches?
vagus nerve
what are examples of laryngeal cartilages?
epiglottis, thyroid, cricoid, arytenoid
examples of muscles of mastication are
Masseter. Temporalis. Lateral pterygoid. Medial pterygoid
what is digastricus
the digastric muscle - important muscle in the neck, which pulls the mandible downward to open the jaw and elevates the hyoid bone for stabilization during swallowing, and it is also involved in chewing and speech
what are the components of pharyngeal arches?
Supportive skeletal elements of the pharyngeal skeleton
Striated muscles that operate the arch
Branchiomeric muscles
Cranial nerves (5, 7, 9, 10) which innervate muscles and provide sensory input to the brain
Aortic arch that connects the ventral and dorsal aortas
The blood vessel dorsal to the arches (dorsal aorta) and the ventral aorta are connected by the aortic arches
what are the components of pharyngeal clefts
Ectodermally-lined grooves on the outside of the embryonic pharynx
Only the first cleft is important
Develops into the external auditory meatus of the ear
Provides the outer epithelium of the tympanic membrane
Clefts are lost in development because of proliferation o f the underlying mesoderm
T/F: The dorsal nerve cord develops from the process of invagination
true
Enumerate the four types of adult structures that arise from the pharyngeal arches
Skeleton
Muscles
Nerves
Blood vessels
where do pharyngeal pouches arise from?
Arises as diverticula/invagination of endoderm of foregut
pharyngeal poches _________ toward the surface of the animal
grow/deepen
these establish the limits of the pharynx
pharyngeal pouch
max. number of pharyngeal pouches in basal shark
8
max. number of pharyngeal pouches in living agnathans
15
Pharyngeal clefts grow toward each pouch and is separated from each other via the _________
pharyngeal plate
Pharyngeal clefts grow toward each pouch and is separated from each other via the pharyngeal plate. If you lose the plate, it will now become the
pharyngeal slit
first pharyngeal pouch derivatives
middle ear cavity
endodermal aspect of tympanic membrane
pharyngotympanic tube
second pharyngeal pouch derivatives
palatine tonsil
third pharyngeal pouch derivatives
inferior parathyroid gland
thymus
fourth and fifth pharyngeal pouches derivatives
superior parathyroid gland
parafollicular cells of the thyroid gland
Formed between the pharynx and the exterior when the pharyngeal plate ruptures
pharyngeal slits
What do you call vertebrates with absent jaw?
agnathans
Which cranial nerve arises from the second pharyngeal arch?
facial nerve
glandular groove in the floor of the pharynx and is involved in filter feeding
endostyle
endostyle gives rise to
thryoid gland
an endocrine that produces hormones
thyroid gland
where does the endostyle/thyroid gland arise from
floor of pharynx
involved in iodine metabolism
significance of muscular postanal tail to many aquatic species
propelling force
Special sense organ to monitor external environment through senses
head
centralization/localization of nervous structures and functions in the head with accompanying dominance of the head
cephalization
what houses most of the visceral organs?
coelom
what surrounds the coelom?
Body wall surrounds the coelom and consists chiefly of muscle, vertebral column, and the ribs
Present in ALL EMBRYOS though adult form may lose this along development
postanal tail
type of Chordates with a NEUROCRANIUM or BRAINCASE
craniates
Animals that have a NOTOCHORD in the embryo stage at least
chordates
T/F: craniates have a three-part brain
true
Chordates with vertebrae
vertebrates
when does the vertebrae appear?
during embryonic development after the notochord has formed
Which group of animals are considered as chordates but NOT as craniates?
protochordates
Enumerate the five fundamental structures in the architecture of vertebrates
Notochord
Dorsal hollow nerve cord
Pharynx
Endostyle or Thyroid Gland
Postanal tail
The science that studies the inheritance of traits from parents to offspring.
genetics
Which of the following is NOT characteristic among agnathans?
presence of a notochord
absence of a jaw
presence of swimbladder
presence of a postanal tail
presence of swimbladder
Which of the following is an important reason for studying comparative vertebrate anatomy?
To understand man's place in the vertebrate world without emphasis on man himself
To comprehend the functional basis of biology
To appreciate the superiority of vertebrates in comparison to lower forms of organisms
To understand the organism-environment interactions of man and the biosphere
To understand man's place in the vertebrate world without emphasis on man himself
Which of the following groups of organisms are classified as deuterostomes?
Cnidaria
Nematoda
Hemichordata
Arthropoda
hemichordata
Which structure separates the pharyngeal cleft/groove from the pharyngeal pouch
pharyngeal plate
Which of the following adult structures are derived from the 3rd pharyngeal pouch?
thymus
incus
palatine tonsil
facial nerve
thymus
which of the following descriptions are TRUE regarding the different pharyngeal components?
Pharyngeal slits are temporary structures for adult animals that breath through gills.
Pharyngeal clefts are lined by ectodermal cells.
Pharyngeal arches give rise to all the cranial nerves.
Gnathostomes have a maximum of 6 pharyngeal pouches during embryonic development.
Pharyngeal clefts are lined by ectodermal cells.
Which of the following is FALSE regarding the regional components of a vertebrate?
The trunk has a coelom which houses most of the organs derived from ectodermal cells.
All craniates posses a three part brain.
Postanal tail may be lost during adulthood among some vertebrates.
Cephalization pertains to the localization of nervous structures in the head.
The trunk has a coelom which houses most of the organs derived from ectodermal cells
Why are protochordates grouped separately from chordates?
Lack of cephalization of sense organs.
Some of the fundamental architectures of chordates are lost during adulthood.
Some of the fundamental architecture of chordates are absent even during embryonic stage.
Failure to develop bony vertebrae during adulthood.
Some of the fundamental architectures of chordates are lost during adulthood.
who proposed a taxonomic classification of deuterostomes
Ernst Haeckel (1874)
deuterostomes are also known as
Also known as ENTEROCOELOMATES
Coelom develops through enterocoely
Four extant phyla (still seen today, present time)
Xenoturbellida
Invertebrate
Echinodermata
Invertebrate
Hemichordata
Chordata
difference of cleavage formation
difference of coelom formation
difference of fate of blastophore
Blastophore forms during gastrulation and connects the archenteron to the exterior of the gastrula
The three-germ layer already formed
Ectoderm outside, endoderm within lining the primitive gut, mesoderm lying between the ectoderm and endoderm
Now develop into two different structures:
Protostome
Blastophore will become the mouth
Deuterostome
Blastophore will become the anus
What is the fate of the blastophore during deuterostome development?
anus
TRUE or FALSE: the indeterminate cleavage of deuterostomes makes it possible for one embryo to give rise to identical twins
true
what are closest relatives of vertebrates along with the hagfish
protochordates
protochordates are composed of
hemichordata
urochordata
describe hemichordates
Acorn worms
Vermiform bottom dwellers found in shallow mud water
Very small but can reach up to 5 feet in length
Very fragile
Note 
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