Lecture 21: Non-bony Vertebrates Flashcards
How many extant species of Vertebrata are there?
Roughly 50 000
What is the primary characteristic of Vertebrata?
Chordates with vertebrae
What does the root word “cranium” mean?
Skull
What is cool about Vertebrata? They have the _______ of any species
The largest animals that have ever lived
What is a vertebral column?
A chain of skeletal elements (cartiliage or bone) surrounding and protecting nerve cord.
Vertebrata have two or more _________, why?
Hox genes
- results of ansertral mutation that duplicated the set of genes
How many Hox genes do non-vertebrata chordates have?
They have only one
What are neural crest cells?
Clusters of embryonic cells that form near dorsal margins of closing neural tube.
What is the function of neural crest cells?
Contribute to formation of bones and cartilages of the cranium, and other structures.
Vertebrata have a ____________ and pronounced _________
endoskeleton
cephalization
What is cephalization?
when the brain is encased in protective plates.
How many sets of eyes do Vertebrata have?
They have one set of eyes.
What is unique about vertebrata’ circulatory system?
- they have a closed circulatory system with a pumping heart
- Hemoglobin in red blood cells
What is the function of pharynheal clefts?
They function as gill slits ancestrally.
What are the Pikaia?
They look like chordate’, but not vertebrata
Do pikaia have carniums
No
What is unique about Haikouichthys?
They posses no braincase or defined eyes.
Do any of the Vertebrata from the cambrian era have clear vetebrae?
No, none of them do.
What are agnathans?
Jawless vertebrates
What does the root word “gnath” mean?
Jaw
Do agnathans have paried fins?
No they have no paired fins
What are Myxini?
They are agnathans called “hagfish”
How many species of Myxini are there?
roughly 20-30 species.
Do myxini posses vertebral elements?
They have very small cartilaginous vertebral elements.
What is cartilage?
A flexible connective tissue with an abundance of collagenous fibers embedded in chondroition sulfate.
What is Cartilaginous?
carnium and other skeletal elements.
How do Myxini eat if they have no jaws, or fins?
They grip the flesh with Keratinous plates in their mouth
They then tie their body into a knot
What is the main mode of self defense for Myxini?
They slime their targets.
What dose the root word “Myxo” mean?
Slime.
What is one reason why Hagfish are indangered?
They are being overfished for their skin
What is the most well known Petromyzontida?
Lampreys
What surrounds the notochord of Petromyzontida?
A cartilaginous tube.
The Cartilaginous tube of Petromyzontida is a primitive ______ _______
Vertebral column.
What are the characteristics of the cephilization on Petromyzontida?
They have eyes with lenses
but no jaws or paired limbs.
Larval Lampreys look and behave like ______
cephalochordates.
How do larval lampreys feed?
through suspension feeding.
How do adult lampreys feed?
they feed through parasitism
What dose the root word -petro- mean?
rock
What dose the root word -myzo- mean?
suck
What dose the root word -Gnath- mean?
Jaw
What is the main characteristic of Gnathostomes?
They have 2 pairs of fins
Extant Gnathostomes have _________ Hox genes
4 clusters
What are Hox genes?
genes that specify regions of the body plan of an embryo along the head-tail axis of animals
What is the origin of the Jaw?
Modifications of 2 pairs of skeletal rods that had supported anterior pharyngeal slits
What happened to the posterior pharyngeal slits?
They became specialized for gas exchange and evolved into gills
What are the most well known Chrondrichthyes
Sharks and rays
What is the endoskeleton of Chrondrichthyes made of?
cartilage.
Are the teeth made of cartilage in Chrondrichthyes as well?
No, they are made of bone.
What is the common name for Chrondrichthyes?
Cartilaginous fish.
What dose the root word -Chondro- mean?
Cartilage
What dose the root word -ichthys- mean?
Fish
What is a fish?
It is a paraphyletic group including any completely aquatic vertebrate that uses gills for respiration
What did the ancestor of Chrondrichthyes have that modern ones do not?
The ancestors had bony skeletons
During the development of most vertebrates, skeleton is first cartilage and then becomes _____________
Ossified.
What dose the root word -os- and -ost- mean?
Bone
where dose the main swimming propulsion of Chrondrichthyes come from?
Comes from the tail
What is the function of the Pectoral fins in Chrondrichthyes?
It adds lift (vertical moment)
How do Chrondrichthyes gain buoyancy?
By storing oil in their liver.
What is unique about sharks skin and teeth?
the teeth appear to be homologous to the jagged scales that make shark skin so tough.
True or false:
Shark teeth continuously replace themselves.
True.
What can Sharks detect through the use of their lateral line?
vibrations in water
What can sharks detect through pores around their head?
Electrical fields generated by muscular movement
How do sharks transfer sperm?
Through copulation.
How do sharks grasp other sharks during copulation?
Males have fins that grip called claspers.
What protects the eggs of most sharks?
A leathery egg case.
How do shark young get nutrients
Vivparous species gain nutrients through
- placenta
- milk
- eating eggs or smaller siblings
What is true about the rear opening of sharks?
Everything comes out of it, Poop, pee, and babies.
What is it called when everything comes out of the same opening?
Cloaca.
What do the larges sharks feed on?
Zooplankton
How do rays and skates (members of the Chrondrichthyes phylum) get around?
By flapping large pectoral fins.
What are the teeth of skates and rays like?
Flat and plate like (for grinding prey)
What are Chimeras?
They are like rays with flat tooth plates, but also have dorsal spines and venom sacs.
Why are Chimeras called Chimeras?
Because they look like they were put together from parts of other fish.
Why are sharks dying off so fast?
- shark watching is becoming popular
- dorsal fins get removed for soup
- they have very low reproductive rate
