Bio 123: PP15 Material Flashcards
What are the 4 key characteristics of Chordates?
1) There is a presence of notochord
2)The nerve cord runs parallel with the notochord and gut, anterior end develops into the brain
3)Gill slits penetrate the wall of a pharynx (at least at some point in embryological development)
4) Tail extends past the anus (at least at some point of their development)
*** All of these features are present is chordate embryos
Do all vertebrata have vertebrates?
NO
What are 2 basic characteristics of Chordates?
They are coelomate and demonstrate bilateral symmetry.
What is the Notochord?
It is a rod of stiffened, but flexible, tissue that helps support the body.
The notochord also later develops into the vertebral column
What are some characteristics of the bodily systems of chordates?
-They have a defined central nervous system
-The pharynx moves from a digestive tract to a respiratory organ
What are the 3 major sub-phyla of chordates?
1) Urochordata (invertebrates)
2) Cephalochordata (invertebrates)
3) Vetebrata
What is a distinguishing characteristics of the vetebrata?
The vertebral column evolves from primitive notochord, composed on individual vertebral bones and are separated by disks (ligaments)
What is the common name for Urochordata?
They are known as sea squirts or tunicates.
What are the characteristics of Urochordata?
-Is the most ancestral sub-phylum of chordates.
-They begin as bilateral larvae swimmers
-Adults display evolutionary reversals
-They have a jellylike tunic around the pharynx
-Most are a few centimeters long
-Live in a variety of aquatic habitats
-Are filter feeders and have an incurrent and outcurrent siphon, gill slits
-The pharynx is a respiratory organ as well
-Gas exchange is done through diffusion
What are some reversals that we see in adult Urochordates?
-Their tail is reabsorbed
-They take on more of a radial symmetry
-Their nerve cord is absorbed into their body
-They gather oxygen through diffusion
-Have a basic circulatory system
What is the tunicate?
The larva form of urochordates
What are the characteristics of Cephalochordata?
-Closets relatives to Vertebrata
-Only 3-7 cm long
-Body display all chordate features throughout their life
-Have a head and a simple brains with neurons
-Have segmented muscles
-Are filter feeders
-Nerve cord sits dorsal to the notocord
-Tail is used for balance
What are some major body characteristics of Cephalochordata?
-Have an eyespot
-Tentacle like structures around the mouth
-Dorsal tubular nerve cord
-Notocord
-Pharynx with gill slits
-tail extending past anus
What are the myomeres?
They are each segmented muslce
What are the characteristics of Vertebrata?
-Pharynx completely shifts to gas exchange
-Accessory digestive organs such as the liver and pancreas
-Have chambered hearts
-Have tripartite brain
-Have advanced sensory structures (increased cephalization)
-Have an affinity for oxygen in red blood cells (hemoglobin)
-Have kidneys
-Have an endocrine system
What does tripartite brain mean?
That the brain have a forebrain, midbrain, and hindbrain