Vert Synapmorphies Flashcards
Vert Synap: _______________________ Endoskeleton
Cartilaginous or Bony
Muscles outside of skeleton -> muscle size less limited
Less energy input into skeleton since it grows with animal (molting UNNECESSARY)
NOT the endoskeleton itself is considered a synap, must be made of one of these 2 things
Cartilaginous Endoskeleton
Reflects ORIGINAL condition - BONY endoskeleton
ALL embryos start with cart. endoskeleton -> fast growth and flexible
Adult hagfishes, lampreys, sharks, and others retain
Hypotheses for origin of bony endoskeleton
Bone in skin of ancient fishes served as protection
Good for muscle attachments - stronger than cartilage
Minerals (e.g., calcium): heart can’t pump w/o calcium
Increased complexity of myomeres (segmented body muscles) - increased control of body
V-shaped in cephalochordates
W-shaped in vertebrates
Pharynx functions as respiratory structure (e.g., extant fish) - ancestrally a filter-feeding apparatus
Pharynx supported by pharyngeal skeleton and muscularized (new muscles evolved)
Vascularization of pharyngeal arches (gills)
Gut evolved from functioning by ciliary action (__________) to muscular action (______________)
ancestral; like pharynx
Evolution of _______________
Accessory glands (e.g., liver, pancreas)
Thus, liver is vert synap
Circulatory system modifications
Enhanced gas and nutrient transport
3 chambered heart, ERYTHROCYTES/RED BLOOD CELLS, HEMOGLOBIN
Closed circulatory system is NOT a vert synap (showed up in amphioxus)
Relieves constraint on size
Enhanced sensory, motor, and integrative control
Evolution ASSOCIATED with predatory habit
Protected ____________ brain (fore/mid/hindbrain)
TRIPARTITE
__________ sense organs
PAIRED
Allow organism to detect things they wouldn’t be able to w/o pairs
Eyes -> photoreceptors Ears -> equilibrium and sound Chemoreceptors -> Taste and smell Lateral line -> water movements Electroreceptors -> prey detection in water
Neural Crest
Cells along neural tube
Give rise to most of cranium, pharyngeal skeleton, dentine, Schwann cells, some endocrine glands
Ectodermal placodes
Plate-like cells on sides
Give rise to olfactory epithelium, eye lens, inner ear epithelium, some cranial nerves, and more
Duplication of Hox genes
Hox genes found in ALL segmented organisms
Ancient genes give developmental identity to body segments (e.g., limbs)
ONE copy in inverts
MULTIPLE copies in vertebrates
–THIS is the synap
May have facilitated evolution of increased complexity of segments in vertebrates
