Lecture Exam #4 Ch. 34 Flashcards
where do the animals called vertebrates get their name from?
vertebrae, the series of bones that make up the backbone
what modern animals did vertebrates give rise to? (3) (ARM)
1) amphibians
2) reptiles (including birds)
3) mammals
how many vertebrates are there on Earth and what do they include?
57,000 and they include some of the largest organisms
what do verterbrates have?
great disparity with a wide range of differences within the group
what do chordates have?
a notochord and a dorsal, hollow nerve cord
what type of animals are chordates and what clade do they belong to?
they are bilaterian and they belong to the clade konwn as dueterostomia
what does chordates comprise?
1) all vertebrates
2) group of invertebrates, the urochordates and cephalochordates
what do all chordates share?
a set of derived characteristics
what do some species of chordates have?
some of the derived traits only during embryonic development
4 key characters of chordates (NDPM)
1) notochord
2) dorsal, hollow nerve cord
3) pharyngeal slits or clefts
4) muscular, post-anal tail
a longitudinal, flexible rod between the digestive tube and nerve cord
notochord
what does the notochord provide?
skeletal support throughout most of the length of the chordate
in most verterbrates what devleops
a more complex, jointed skeletal and the adult retains only the remnants of the embroynoic notochord
what does the nerve cord of a chordate embryo develop from?
a plate of ectoderm that rolls into a tube dorsal to the notochord
what does the nerve cord develop into?
the central nervous system (the brain and the spinal cord)
found in most chordates, grooves in the pharynx that develop into slits that open to the outside of the body
pharyngeal clefts
functions of the pharyngeal slits (3) (SGD)
1) suspension- feeding structures in many inveterbrate chordates
2) gas exchange in vertebrates (except vertebrates with limbs, the tetrapods)
3) develop into parts of the ear, head and neck in tetrapods
in many chordate species what is greatly reduced during embryonic development?
the tail
what does the tail provide in many aquatic animals?
propelling force
what are lancelets (cephalochordata) named for?
their bladelike shape
what type of feeders are lancelets?
marine suspension feeders
what do lancelets retain as adults?
the characteristics of the chordate body plan
what is more closely related to chordates than lancelets?
tunicates
when does tunicates most resemble chordates?
during their larval stage (which may only last a few min)