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Bio 242- Week 8 Notes (exam 3)

by: LaKeisha Crum

Bio 242- Week 8 Notes (exam 3) BIOL 242

Marketplace > University of Louisville > Biology > BIOL 242 > Bio 242 Week 8 Notes exam 3
LaKeisha Crum
U of L

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About this Document

These notes cover the first day of Exam 3 notes. Chordates up to the amniotes.
Diversity of Life
James Alexander
Class Notes
Chordates, Tetrapods, Amniotes
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This 4 page Class Notes was uploaded by LaKeisha Crum on Friday October 14, 2016. The Class Notes belongs to BIOL 242 at University of Louisville taught by James Alexander in Fall 2016. Since its upload, it has received 14 views. For similar materials see Diversity of Life in Biology at University of Louisville.


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Date Created: 10/14/16
Bio 242­ Exam 3 (Week 8 Notes)  Chordates:   Dorsal, hollow nerve cord (this was different from the protostomes who had a ventral  nerve cord.   Notochord­ cartilaginous structure (vestiges stay to form the vertebral column)   Pharyngeal gill slits­ go on to form the jaw and inner ear   Postanal tails­ (coccyx in us, grows past the anus  Close circulatory system   Radial, indeterminate system  Advanced excretory system­ humoral defense and cellular defense  Cephalochordata: lancelets ­ Ring of tentacles around the mouth filters water into the gill slits to goes into the atrium  and then out of the atripore. TIP: To remember the order just remember that it is  alphabetically backwards. It goes through the pharyngeal gill slits, to the atrium, and  then the atripore.  If food is in the water, it is grabbed by mucous in the gill slits and then it is redirected to the anus.  ­ Segments­ chevron muscles (v­shaped) ­ They are found next to the water line in marine environments.  Urochordata: sea squirts (also called tunicates) ­ You can squeeze them and a small amount of water will come out due to the contraction  of muscles around the siphon (Vocab Review: siphons are tubes that water flows  through) ­ 2 siphons for water in and out  ­ Filter feeders as adults ­ Lose notochord ­ Sessile ­ Expanded pharynx ­ Tunicin= rough outer coats (why they are also called tunicates) ­ Has larvae that resemble the cephalochordata  Sea squirt Hagfishes ­ Larger bodies that look like eels (tubular body) ­ Rasping tongue with teeth to tear off chunks of prey ­ Scavengers and Carnivores­ recycle dead animals (whales) by plowing into their bodies  and decomposing it ­ Lack Jaws ­ We used to say that they lacked vertebrae but they are recently shown to have  rudimentary vertebrae (analogous to us)  ­ No scales ­ Retain notochord  ­ Make a lot of slime to help them burrow and to protect themselves (animals like us  cannot keep a hold of them). Also used to protect against bacteria ­ Can make knots in their body (like shoe string) to help them plow into the body of the  dead ­ No paired appendages ­ One pair of semicircular canals (Like our inner ear that helps us with balance) to tell them where their head is  ­ Iso­osmotic­ liquid on inside of their body is as strong as the sea water so no osmosis  occurs.   Cephaladpidomorphi  ­ (lampreys or petromyzontida) ­ Very large with larvae similar to that of the lancelets  ­ Notochord stays until adulthood like the hagfish ­ Circular mouth with keratinized teeth  ­ Rasping tongue ­ Carve out circular holes in the prey (live off of other fish)  ­ Two pairs of semicircular canals (for balance)  ­ Regulate their body fluid (more advanced than the hagfishes) Gnathostomes :  (“gnatho”= to chew or a jaw) Jawed Vertebrates  Gill support structure becomes jaws and middle ear bones (skeletal rods around the  pharynx generate the jaw and ear bones)   Have jaws and teeth with enamel   Paired limbs   3 pairs of semicircular canals (good idea of where their heads are)   Well­developed brains with ganglia (clusters of nerve cells) Chondrichthyes­ cartilaginous fish (rays, sharks, skates) ­ first group of jawed fishes ­ Gills for respiration ­ Reproduction:  Oviparous­ to lay eggs. TIP: “Ovi” sounds like ova Viviparous­ to give birth to live animals. TIP: “Viva” means live  Ovoviviparous­ egg live laying. (These produce eggs but retain them. The eggs grow inside of  them and then the actual offspring is birthed). TIP: it is ova and live blended together, so they do  both.  ­ Hearts with 2 chambers (One atrium and one ventricle)  ­ Cartilage bones­ this is an apomorphy (Vocab Review­ derived trait) ­ Placoid scales (Like our nails, made of keratin, stick out of the surface of the skin)  ­ Tail provides propulsion (Other fins for stabilizing) ­ Torpedo shaped body ­ Must continue to swim to breathe (float around when they are asleep). Must move to keep water moving through their gills to obtain oxygen.  ­ Buoyancy by oils  Osteichthyes: the bony fish *most abundant vertebrate* TIP: “Ost” is usually used in words  referring to bones such as ossicles and osteoporosis  ­ Structure: Mouth, anus, caudal fin (end of body­ tail), postanal tail, swim bladder,  stomach, gonads, liver, two pairs of fins, nostrils( for chemosensory­ not connected to  respiratory system like ours), scales that cover the entire outer layers of skin to prevent  water loss and bacterial attack (like our skin) ­ Operculum­ flat like cover that surrounds the gills but with an opening to allow water to  pass out TIP: the “oper” in the word kind of  looks like open and it is a  flap that covers an opening  Tetrapods : four limbs TIP: “tetra” means four like tetrahedron.  ­ Four classes­ amphibians, reptiles, birds, and mammals  ­ Pectoral, pelvic girdle,  ­ Lung, double circulatory system (pulmonary and systemic)  Amphibians­ frogs and salamanders ­ Smooth, moist, glandular skin ­ Return to water to lay eggs ­ Lungs and may breathe through their skin, aquatic have gills ­ Closed circulatory system with three chambers (1 ventricle and two atrium)  Amniotes= shelled eggs to prevent desiccation.  ­ Four extra membranes­   Allantois­ stores wastes, gas exchange Chorion­ gas exchange outermost membrane Yolk Sac: yolk and albumin for protein and food Amnion­ immediately surrounds the embryo. Called the “internal ocean”. Cushions and protects  the embryo.  ­ 3­4 Chambered hearts ­ Urea or ammonia produced (produce guanine as well as waste) ­ Tough, leathery skin ­ Strong jaw muscles­ can be lifted off of the ground due to jaw muscles ­ Internal fertilization­ low number of sperm because they are safer this way. Sperm dries  out in the dry air  ­ Efficient circulatory and respiration systems  ­ +/­ pressure breathing


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