Post on 02-Jan-2016
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Chordate Embryos and Tissues
• Chordates have 3 layers of tissue• Deutersomes
– Anus forms first, then the mouth forms
• Coelomates• Bilaterial symmetry• Endoskeleton• Complete digestive system
Tunicates(subphylum Urochordata)
• The deepest branching lineage of chordates.• Resembles other chordates most intensely during
larval stages• Larva tunicate settles down, and goes through
metamorphasis– Many chordate characteristics disappear
• Tail and notochord go away, nervous system is destroyed• Often called “sea squirts” as they shoot out water from their
anus to jet away when attacked
Lancelet(subphylum cephalochordata)
• Named after their bladelike shape• Lancelet Larvae:
– Devolop a notochord, dorsal, hollow nervecord, pharyngeal slits, and post-anal tail
– Food source is plankton
• Post metamorphasis:– Spend most of their time in the sand, leaving their mouth
exposed, catching their food. – Segmented muscle developed from somites - found in all
chordate embryos
Craniates• craniates (literally means cranium/skull) are unique
from their other chordate relatives in a number of characteristics:– Possess 2 clusters of ‘Hox’ genes– Neural Crest - collection of cells at the dorsal margins in an
embryo which give rise to a variety of structures:• Teeth• Many bones and cartilage of the skull• Inner layer of skin (dermis) on the facial region• Sensory capsules in which sense organs such as eyes develop.
-Pacific Hagfish-
Myxini
•These bad boys have a skull made of cartilage, and swim in a snake-like motion
•They Also have a small brain, eyes, ears, and a nasal opening which connects to their pharynx
Vertebrata Craniates Lampreys (Cephalaspidomorphi) are the oldest living lineage
of vertebrates, and lack a jaw
Vertebrata Craniates Conodonts (“cone teeth”)
•Early, slender, soft-bodied verebrates with advanced eyes, and lacked a jaw
Vertebrata Craniates OstracodermsAdditional vertebrates stemmed from the same period. Ostracoderms -- had paired fins, inner ear and sense of balance, a muscular pharynx, and armored bodies
Vertebrata Craniates Gnathostomes (“jaw mouth”) = jawed vertebrates
• The jaw enabled animals to grip food and chew it up for digestion• 4 Hox Genes• Enhanced sense of smell and vision resulted in a larger forebrain• Have lateral line systems, which detected vibrations• Consisted of placoderms = “plate-skinned” and acanthodians, which are closely related to ray-finned fish and lobe-finned fish• Went extinct around 360 million years ago
Vertebrata Craniates Chondrichthyans
• Consists of Sharks, rays, and their close relatives• Have skeleton made mostly of cartilage and loads of calcium, developed mostly in embryonic stages
Sharks:• have a spiral valve, which makes up for the sharks short digestive tract• Have noses meant only for smelling, not breathing• Eggs fertelized internally
• Some species are oviparous• Some species are ovoviviparous
Rays:• Bottom-dwellers, whiplike tails, venomous barbs
Vertebrata Craniates Osteichthyes (“Bony Fish”)
• Bony endoskeletaon• Breathe through gills
• protected by bony flaps called operculum• Buoyancy controlled with an air sac called a swim bladder
Common fish
Vertebrata Craniates Osteichthyes continued…
Ray-Finned Fishes• Majority of aquatic osteichthyans• Bass, trout, perch, tuna, herring• Fins allow for increased
• maneuverability• defense
Blue-Fin Tuna
Vertebrata Craniates Osteichthyes continued…
Lobe-Fins• Fins have a thick muscle layer in pectoral and pelvic fins• Used to “walk” across the sea floor• Only three lineages left today
• Coelacanths, lungfishes, and tetrapods
Coelacanthslungfish
Vertebrata Craniates Tetrrapods -- gnathostomes with feet
• Have 4 feet with digits• Able to support weight on land• No gill slits
• in embryonic development, what would have developed into gill slits creates ears and glands
• Overall, adaptions making organisms fit for land
Vertebrata CraniatesFirst Group of Tetrapods: Amphibians
• 4,800 species today:• Comprising of salamanders, frogs and caecilians
• Live on land and in water• Scientists believe that the earliest tetrapods were heavily tied to water
Sources• http://depts.washington.edu/fhlk12/links/StudentProjects/Images/CionaTunicateBiology/tadpole_low.gif • http://lh3.ggpht.com/_yItZwKwfM-I/TTPNPSBC1LI/AAAAAAAAA_U/HobmwJ3weYo/chordatecharaceristic
s219.jpg• http://www.blc.arizona.edu/courses/schaffer/182/Vertebrates/AmphioxusPurvis.jpeg• http://www.blc.arizona.edu/courses/schaffer/182/Vertebrates/AmphioxusPurvis.jpeg• http://www.google.com/imgres?um=1&hl=en&biw=1290&bih=658&tbm=isch&tbnid=vC0HTQ2FBF6zuM:
&imgrefurl=http://northgoessouth.com/tag/giant-bluefin-tuna/&docid=meFYCiQ-KwXP0M&imgurl=http://northgoessouth.com/wp-content/uploads/2010/07/27Tuna-t_CA0-articleLarge.jpg&w=600&h=315&ei=axmOT8KNEsGo2wXvvr2DDA&zoom=1&iact=hc&vpx=170&vpy=384&dur=1148&hovh=163&hovw=310&tx=199&ty=95&sig=110107029035550495494&page=2&tbnh=110&tbnw=209&start=18&ndsp=20&ved=1t:429,r:15,s:18,i:224
• http://www.google.com/imgres?um=1&hl=en&biw=1290&bih=658&tbm=isch&tbnid=mEB3K2EHov4tkM:&imgrefurl=http://www.richardherrmann.com/PersonalProjects/GameFish.html&docid=QxMmdZhCQxO_NM&imgurl=http://www.richardherrmann.com/PersonalProjects/images-persProjects/05BluefinTuna011637.jpg&w=700&h=518&ei=axmOT8KNEsGo2wXvvr2DDA&zoom=1&iact=hc&vpx=777&vpy=210&dur=1074&hovh=193&hovw=261&tx=118&ty=118&sig=110107029035550495494&page=3&tbnh=151&tbnw=199&start=38&ndsp=23&ved=1t:429,r:14,s:38,i:266
• http://images.nationalgeographic.com/wpf/media-live/photos/000/005/cache/giant-stingray-bluesheet_547_600x450.jpg
Sources part 2• http://www.biog1105-1106.org/labs/deuts/chordates.html• jaws.jpg (640×480)• http://www.google.com/imgres?um=1&hl=en&biw=1290&bih=658&tbm=isch&tbnid=1QBTNyeBRDnkjM:&imgrefurl=http:/
/palaeos.com/vertebrates/gnathostomata/gnathostomata.html&docid=ZJEYZYbF12ssWM&imgurl=http://palaeos.com/vertebrates/gnathostomata/images/Gnathostomata1.jpg&w=400&h=262&ei=aw2OT6X5BIXs2QWvgvSgDA&zoom=1&iact=rc&dur=598&sig=110107029035550495494&page=2&tbnh=107&tbnw=163&start=19&ndsp=22&ved=1t:429,r:8,s:19,i:145&tx=122&ty=70
• http://www.google.com/imgres?start=89&um=1&hl=en&biw=1290&bih=658&tbm=isch&tbnid=C4sKRRafgcCXkM:&imgrefurl=http://palaeos.com/vertebrates/bones/gill_arches/epibranchial.html&docid=WvfSn5InEtkJlM&imgurl=http://palaeos.com/vertebrates/bones/gill_arches/images/TristychiusRecon.gif&w=500&h=143&ei=QQ2OT7SgBqjW2AXIoemiDA&zoom=1&iact=rc&dur=211&sig=110107029035550495494&page=5&tbnh=56&tbnw=195&ndsp=24&ved=1t:429,r:12,s:89,i:31&tx=155&ty=32
• https://www.google.com/search?q=neil+patrick+harris&um=1&ie=UTF-8&hl=en&tbm=isch&source=og&sa=N&tab=wi&ei=RAKOT4iSDMKcgQfe3Y3yDQ&biw=1290&bih=658&sei=RwKOT560DMjq2QXe_KWfDA
• http://30.media.tumblr.com/tumblr_lb0tidWR5R1qd8z9zo1_250.gif• http://upload.wikimedia.org/wikipedia/commons/c/cd/Tunicate_komodo.jpg• http://tolweb.org/Craniata• http://cdn.physorg.com/newman/gfx/news/hagfish.jpg• http://farm4.static.flickr.com/3357/3476498612_d29a5984ed.jpg