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Do fish have eyelids? |
Do fish have eyelids?
The Class Osteichthyes:
Lobe-finned fish
Known only as a fossil until 1938.
Has paddle-like fins with a fleshy base.
Lungfish
Have lungs, internal organs for gas exchange between air and the blood.
Only a few species are known.
Ray-finned fish
Fins are supported by stiff rays and/or bony spines.
All other bony fish, both freshwater and saltwater, are in this group.
Types of scales and body movement:
The circulatory system of simple vertebrates:
Spawning: the external fertilization of fish eggs.
Research Links:
Types of fins and the motion they produce:
Dorsal - top of body - helps keep the body upright.
Caudal - the "tail fin" - provides forward motion.
Anal - located just anterior to anus - helps keep the body upright.
Pelvic - paired fins on ventral surface - turns fish left or right and backward.
Pectoral - paired fins behind the gills - moves fish up or down.
Adipose (catfish & trout) - a fleshy fin between dorsal and caudal fins - no motion.
Lateral line:
A row of scales with
sensory depressions down each side of the fish.
This system detects vibrations in the water.
Chromatophores: structures containing pigment to provide color patterns.
No eyelids:
Most fish have large eyes to help gather light in dim surroundings.
In bright surroundings, this causes fish to seek shadows.
Gills:
external tissue rich with blood vessels to exchange gases with the water.
Operculum - a hard plate on either side of the head that protects the gills and opens at the rear to allow water to flow through the mouth and over the gills.
Swim bladder:
A thin-walled sac along the top of the abdominal cavity containing a mixture of oxygen, carbon dioxide, and nitrogen obtained from the bloodstream.
The swim bladder usually produces neutral buoyancy, but some fish are able to adjust their buoyancy by slightly changing the amount of gas in the swim bladder.
Almost all fish have a swim bladder. Those without one, like sharks and freshwater darters, sink if they stop moving their fins.
Yes, fish can talk!
The nervous system of simple vertebrates:
Atrium -
Ventricle - the pumping chamber.
Forebrain:
Midbrain:
Hindbrain:
Cranial - connect major sense organs directly to the brain.
Spinal - connect internal organs and muscles to the spinal cord. (6)
In many fish species, the male uses his fins to make a depression to use as a "nest".
He then tries to guide a female to the nest to release her eggs.
He swims over the eggs and releases his milt, a
fluid containing the sperm. This "external fertilization" is inefficient, but having the eggs in the depression helps.
In most cases, the female will guard the nest until the eggs hatch. After that, the hatchlings are on their own.
3.1c
Assignment - Chordates, Vertebrates & Fish
