Lamprey on a Salmon Video Video. Lamprey Anatomy.

Lamprey on a SalmonVideo

Lamprey Anatomy

Critical Thinking???

• Hagfishes have tiny eyes buried beneath the skin and lampreys have large, exposed eyes. Explain how each type of eye is an adaptation for feeding style.

Critical Thinking???

• How & why would the respiration process differ from a lamprey to a bony fish?

Interpret This Graph

Marine FishesClass Osteichthyes – Bony fishes; the most prominent group of vertebrates, they

include about 24,000 species.

In addition to having a bony skeleton, there are some other major differences between bony and cartilaginous fishes.

Marine Fishes

Bony and cartilaginous fishes also have very different strategies for maintaining theirposition within the water column.

Most bony fishes use a swim bladder for lift, whereas most sharks rely on theswimming generated lift that is a function of the fluid dynamics of their fins and tail.

Both groups do however use bands of muscle called myomeres to generate the basicundulating motions of the body.

There are many exceptions though…

Marine Fishes

There is however great variationto the basic themes of movement,as well as the body shapes thatare best adapted to differentenvironments and differentswimming habits…

Marine Fishes - Coloration

The color of bony fishes is typically found in special cells in the skin called chromatophores.

Different chromatophores, each with varying amounts of pigments, can dictatethe basic color pattern of the different fishes.

Many fishes can even change their coloration based on their environmental conditions (for predation, avoidance of predation, and communication with others of the same species).

Examples of general fish coloration patterns:

Warning coloration

Cryptic coloration

Disruptive coloration

Countershading

Marine Fishes – Circulatory System

The circulatory system of all fishes are based on a two-chambered hearts that pumpblood to the gills, from where the oxygenated blood is carried to the bodythrough arteries and capillaries, before returning to the heart through theveins.

Marine Fishes – Circulatory System

The mechanism for irrigating the gills is different for bony and cartilaginous fishes.

Cartilaginous fishes:

Bony fishes:

Spiracles

Marine Fishes – Circulatory System

Gas exchange occurs in the gills, where a counter-current flowing blood/water system allows for very efficient oxygenation of theblood…

Marine Fishes – Sensory SystemMarine fishes have well developed nervous and sensory systems.

Many have a great sense of smell. Their nostrils open to olfactorysacs on both sides of the head. Some sharks can detectblood at concentrations as little as one part per million!

Fishes detect taste with their taste buds in their mouth, as well ason their barbels (whisker-like organs found around the mouths of some bottom dwelling fishes).

Most fish have a somewhat well developed sense of vision. Some shallow water bony fishes have color vision, but most fishesdo not… also, focusing is done by moving the lens as supposedto changing it’s shape…

Some cartilaginous fish have sensory organs around the head calledampullae of Lorenzini. They can detect week electrical fieldsthat may be used for navigation, as well as for detecting prey.

Most fishes can also perceive sounds with their inner ear, and they can detectchanges in their position within the water column using their earstones or otoliths… (nerve cells detect changes in positioning).