BIO 474 Study Guide - Winter 2018, Comprehensive Midterm Notes - Muscle, Bone, Skin
BIO 474
MIDTERM EXAM
STUDY GUIDE
Fall 2018
Conodants
Early group of fish with mineralized tissue, notochord, cranium, but lacked pharyngeal slits
Where did vertebrate life originate?
The efficiency of the vertebrate kidney at removing water from the body points to vertebrate life
originating in freshwater where there was an abundance of water. On the other hand, the earliest
vertebrate fossils are found exclusively in marine environments.
Agnathans
Paraphyletic group of jawless extant vertebrates without reproductive ducts who reproduce externally
Hagfishes
Essentially the only extant Agnathans who are found at 1% males in a population (possibly
hermaphroditic). They lack jaws, vertebra, external armor, are found worldwide (except for polar
waters) \, and feed as scavengers.
Distribution vs. range
Range refers to the distance an individual will travel while distribution refers to the regions in which a
species can be found.
Lampreys
Have small simple vertebrae, feed as parasites by drinking blood, have well-developed kidneys to allow
them to reproduce in freshwater (making them Anadromous), and are sedentary filter-feeders as larvae.
They respire via gill tissue where water exits it's gills, using tidal ventilation instead of flow-through
ventilation since they may be fixed to their prey at times.
Benefits of jaws
Bite, chew, eat larger prey than self, speak, grip, facial expressions, talk, defense, digging,/burrowing,
forceful ventilation. Jaws likely developed from mutated gill arch bones. Jawed teeth are derived from
the jaw bone, unlike previous teeth, which were dermal bone.
Placoderms
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Early jawed fish derived from ostracoderms that lacked teeth. They were covered with a thick bony
shield that was separated in to a head and trunk portion unlike ostracoderms. They began as marine
organisms but the fossil records show an evolution to fresh water living. They have an extra pelvic lobe
similar to that of sharks called "claspers" used for copulation believed to be the origin of sex since the
placoderms fertilized internally.
Viviperous
Offspring born living
Oviperous
Offspring born from an egg
Acanthodians
After Placoderms, these had 6 pairs of fins.
Buchal pumping
using muscular contractions to force water out of the Buchal (oral) cavity
Ram ventilation
Swimming with an open mouth to allow water to flow through the gills for respiration
Gill tissue structure
Primary lamellae with secondary lamellae that have capillaries within them with a thickness of 1 cell to
allow for gas exchange. The primary lamellae have abductor muscles that when contracted allow water
to flow between the lamellae rather than around, increasing oxygen uptake.
Countercurrent exchange
Blood and water flow in opposite directions within the gill tissue to maximize O2 uptake rather than
them equilibrating as it would if they flowed in the same direction (lateral to medial blood flow).
Increased O2 uptake allows for increased activity due to more metabolic resources. Also used for
thermoregulation where heat is maintained in the organism's core. It allows muscle temperatures to
drop more slowly than outside water temperature.
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Early group of fish with mineralized tissue, notochord, cranium, but lacked pharyngeal slits. The efficiency of the vertebrate kidney at removing water from the body points to vertebrate life originating in freshwater where there was an abundance of water. On the other hand, the earliest vertebrate fossils are found exclusively in marine environments. Paraphyletic group of jawless extant vertebrates without reproductive ducts who reproduce externally. Essentially the only extant agnathans who are found at 1% males in a population (possibly hermaphroditic). They lack jaws, vertebra, external armor, are found worldwide (except for polar waters) \, and feed as scavengers. Range refers to the distance an individual will travel while distribution refers to the regions in which a species can be found. Have small simple vertebrae, feed as parasites by drinking blood, have well-developed kidneys to allow them to reproduce in freshwater (making them anadromous), and are sedentary filter-feeders as larvae.
