Lectures Eight-Nine: Bony Fish Flashcards
Most modern radiation of ray-finned fishes:
Neopterygii
With a bony skeleton, what increases?
Density
How do bony fish combat their tendency to sink due to their denser bones?
Swim bladder
How did the swim bladder allow for the transition to land?
Precursor to lung
How has mouth placement changes from cartilaginous to bony fish?
Subterminal to terminal
How have caudal fins changed from cartilaginous to bony fish?
Heterocercal to Homocercal
Do bony fish have a greater variety of body shapes than cartilaginous fish?
Yes
Which vertebrate group has the most extant number of species?
Bony fish
Why might bony fish be the most successful vertebrate group?
They are found EVERYWHERE there is water
What is an important takeaway from the documentary clip we watched about energy expenditure?
- Everything costs energy when living in the wild
In order to survive, how must energy flow?
More in than out
How do shoals come together?
There’s a genetic component that informs the fish which chemical signal to be attracted to.
What would happen to fish in a shoal if they were not constantly changing position?
They would suffocate.
How might a fish know its a full moon (to time the tides well)?
They probably don’t. It’s likely another factor that corresponds to the full moon that is perceived.
Who tends to be larger, female or male vertebrates? Why?
When/why might this be reversed?
Females are larger than males. Being a female costs a lot more energy due to reproductive needs.
The male is usually only larger if there is a dominance display associated with mating.
How does endochondral bone (long bones) originate?
First forms as cartilage then becomes bone.
How does dermal bone originate?
Starts as bine but keeps growing.
Why are ray-finned fishes called ray-finned fishes?
They have bony rays extending out into their fins.
What 6 changes to anatomy happen in ray-finned fishes?
- Pectoral fins move up to the side of the body.
- Pelvic fins move forward (the most posterior ventral fins are anal)
- Heterocercal tail to homocercal tail
- Gill slits -> bony operculum cover
- More muscles in the head to move operculum
- Jaw structure change to project jaws
Did lobe- or ray-finned fishes evolve first?
Lobe-finned
How does internal bony structure of fins differ between ray- and lobe-finned fishes?
Lobe: Bone extends out into fins (later became tetrapod limbs)
Ray: Ray-like projections of bone
Describe fin placement in lobe-finned fishes.
Pectoral and pelvic fins located similarly to in Chondrichthyes. In standard “limb” placement.
Describe placoid scales.
Found in sharks and rays.
Tooth-like, with blood supply. Stay the same size.
What is the purpose of scales?
Protect the outside of the body.
Prevents diffusion, allowing for more controlled osmoregulation.
