Lecture 8 DA Flashcards
What are 6 characteristics of subphylum vertebra?
Hollow dorsal nerve cord, extends into the brain anteriorly.
Internal skeletal cranium protects brain.
Notochord terminates at the cranium’s base.
Head, trunk and post anal tail.
Well developed ventral heart.
Have pharyngeal slits.
What is a feature of advanced clades in subphylum vertebra?
Notochord is replaced by cartilaginous or bony vertebral column.
What does the notochord evolve into? What about paired fins and gills?
Notochord - vertebral column
Paired fins - limbs
Gills - lungs
What are fish?
Aquatic vertebra with gills.
What can be a fish?
Anything that isn’t a fish.
If appendages are present on fish, what are they usually?
Fins.
What is the skin of fish like?
Covered in scales.
What is the most diverse group of vertebrates?
Fish (jawed specifically).
What do fish dominate?
Fauna of aquatic environments.
What did tetrapods evolve from exactly?
Sarcopterygii - the rhipidistians.
What did all fish descend from?
Unknown free swimming protochordate.
What are agnatha?
Jawless fish.
What kind of body and skeleton do agnatha have?
Cylindrical body with cartilaginous skeleton.
What is the tail of agnatha like? Is it symmetrical?
Heterocercal tail, not symmetrical.
Do agnatha have paired fins? What about ventral fins? What are their fins in general like?
No paired fins, or ventral fins. Fins have a broad base.
What are the two classes of agnatha, and their common names?
Myxini - hagfish
Petromyzontida - lamprey
What is the water environment of myxini?
Entirely marine.
What do myxini feed on?
Dead or dying fish.
How are myxini adapted to feeding?
Attach to food using keratinised plates. Tear food using rapss. Ties a knot in its body for leverage.
Do myxini produce slime?
Yes.
Do myxini have larva?
No, large eggs, but no larva.
Do myxini have osmoregulation?
No.
What is the water environment of petromyzontida?
Marine or freshwater.
Where do all petromyzontida spawn?
Freshwater streams.