L2 - Fish Anatomy Flashcards
How did the loss of external armour help chondrocytes?
Increased their mobility and their ability to escape from predators
Wahat fins do chondrocytes have?
Pectoral, Pelvic and Dorsal
How do each move?
a) sharks
b) skates and rays
a) Via their tail and pelvic fins
b) undulating movements of their enlarged pectoral fins
What feature did most Osteichthyes develop to supplement their gills?
Air filled sacs - in most species these has evolved into swim bladders
Briefly describe how fish evolved from the water to being terrestrial animals
1) gills were inadequate for low O2 waters, so lunglike sacs developed to supplement the gills in some bony fish
2) this allowed them to breath air and leave the water temporarily
3) Lungfish were important predators in the Devonian period but only 6 species survive
What is another name for the tail of a fish?
Caudal fin
Where is the adipose fin found?
present on the mid-dorsal line of some teleosts such as salmonids
Where are the pectoral fins positioned?
- Carried on the pectoral girdle
- located dorsally or ventrally behind the operaculum - the more dorsal the fins the more advanced
- used for steering and propulsion
Where are the pelvic fins? give one specialised form
- They are located on the fishes pelvis usually half way down the fish
- They are in front of the anal fins
- Specialisation = pelvic adhesion - specialised into a sucker
What is the function of dorsal fins?
- stabilise the fish and prevent it from rolling
- acts as a pivot during fast turns
- may be used defensively - venomous such as in the weaver, stone and scorpion fish
In terms of the caudal peduncle, what is seen in advanced teleosts and why?
A narrow CP as it allows for efficient high speed sustained locomotion using propulsion created by the caudal fin
In fish what is each used for?
a) white muscle
b) red muscle
a) white muscle - used for rapid swimming (escape), is the majority of the fish
b) red muscle - used for steady sustained swimming
What is an otolith and what can it be used for?
It is the ear bone of a fish and can be used to age and look at the growth history of the fish
Shape is species dependent
State which fish each kind scale belongs to:
a) Placoid
b) Cosmoid
c) Ganoid
d) Cycloid
e) Ctenoid
a) Placoid - sharks
b) Cosmoid - lungfish
c) Ganoid - bowfish and sturgeon
d) Cycloid - trout and herring
e) Ctenoid - sole and perch
What is special about the scales of cycloids?
They are transparent to allow light to pass through and the reflective properties of guanine crystals in their skin to show
They also provide a growth record
