Fishes Lecture Flashcards
Cyclostomata synapomorphies
Circular mouth
Single median nostril
Branchial basket
Velum
Rasping tongue supported by cartilage (lingual cartilage)
Myxiniformes anatomy and ecology
Degenerate eyes
Barbels
Single semicircular canal situated at an angle
Vary in gill slits
Single median fin
Direct development
Petromyzontiformes anatomy and ecology
2 dorsal fins
Caudal fin
Eye
Pineal eye
Buccal funnel
2 semicircular canals
Indirect development (larval stage)
Ectoparasitic
Anadromous
Myxiniformes metabolism and tonicity relative to environment. Why?
Low metabolism, osmoconformers. Cannot support active transport needed to have a different tonicity relative to their surroundings
Petromyzontiformes metabolism and tonicity relative to environment. Why?
Higher metabolism, osmoregulators. Are able to support active transport between environment and tissues
What can you infer about the Petromyzontiform kidney?
Used to help osmoregulate
Why is it important for Petromyzontiformes to be osmoregulators?
Relative salt concentration between tissues and environment changes between life stages. Juveniles are found in fresh water and must transport salt into their tissues and vice versa for adults
What traits do gnathostomes have that cyclostomes do not?
Paired fins and limbs
Increase in metabolism
Larger forebrain (receives more sensory info)
3 semicircular canals
Lateral paired gills rather than midline
Mineralized tissues (bones, teeth)
Paired nasals
Jaws
Describe the development of paired nasals in gnathostomes
In gnathostomes, the nasohypophyseal plate has split into two nasal placodes and the adenohypophyseal placode. This splitting allowed the mandibular mesoderm to migrate farther into the head along with the mandibular neural crest cells to form the upper and lower jaws
What is developmental bias/constraint? Give an example
Due to development, not all morphological variation is equally probable.
Ex. mandibular mesoderm could not migrate with neural crest cells due to nasohypophyseal plate in Cyclostomata, so it was unlikely for them to develop two nasal passages
What are the developmental contributors to the vertebrate skull?
Neural crest cells and the mesoderm + neural crest cells
What type of cell is an osteocyte?
A cell that makes bone
What type of cell is an osteoblast?
A cell that makes osteocytes
What type of cell is an osteoclast?
A cell that destroys osteocytes
What are the bone types of the vertebrate skull?
Dermal bone and endochondral bone
What is endochondral ossification?
The process of developing bone from existing cartilage
What are the developmental contributors, bone types, and functions of the chondrocranium?
Neural crest cells + mesoderm, endochondral bone, functions as a brain case
What are the developmental contributors, bone types, and functions of the dermatocranium?
Neural crest cells, dermal bone, functions as the covering of the brain case and palate of the mouth
What are the developmental contributors, bone types, and functions of the splanchnocranium?
Neural crest cells, endochondral bone, supports gill arches and throat plus helps in the formation of jaws
Where is dermal bone found in the vertebrate skull?
Dermatocranium
Where is endochondral bone found in the vertebrate skull?
Chondrocranium and splanchnocranium
What is the biggest difference in the ventilation structures of a Lamprey and a Hagfish?
Hagfishes have a nostril that connects to the oral cavity. The nostril of a Lamprey does not connect to its oral cavity.
What happens in the development of Cyclostomes that causes them to not form jaws?
The nasohypophyseal placode blocks the migration of of mandibular tissue toward and around the mouth.
What do the premandibular/mandibular mesoderm form from?
Neural crest