Bio 123: PP16 Material Flashcards
What starts the class of fish?
Chondrichthyes
What are the sub classes to Chondrichthyes?
Holocephali and elasmobranchii
What is a unique characteristic we begin to see with Chondrichthyes?
They begin to have jaws.
What is the study of fish?
Ichthyology
-Chon
means having cartilage
What is the purpose of having pointed bodies?
It allows for efficient hydrodynamic movement
What are some characteristics of Chondrichthyes?
-about 900 species
-Cartilaginous skeleton
-oily liver
-5-7 pairs of external gill slits
-3 pairs of semicircular canals
-Almost all viviparous
-two chambered heart
-heterocercal caudal fin
-pelvic claspers
-placoid scales
-ventral. outh and polyphydont teeth
What is the purpose of the liver in chondrichthyes??
It plays a dual function where it takes care of toxins in the body and regulate fat. It is also now full of vacuoles that help it maintain buoyancy.
Viviparous
giving birth to live young
oviparous
being born from an egg
What is the purpose of pelvic claspers?
Helps male sharks keep female sharks in place since they are not as willing to mate. The claspers attach to the females and inflict pain if they begin to move too much or try to fight the male sharks.
Define polyphydont teeth in sharks
They keep constantly growing where older teeth are in the front and newer teeth are in the back.
What are the variations of the caudal fin?
Heterocercal (shark)
Diphycercal (lungfish)
Homocercal (perch)
What is the ancestral form of the caudal fin?
The heterocercal tail
What are the variations of scales in fish?
-Placoid scales (cartilaginous fishes)
-Ganoid scales (nonteleost bony fishes)
-Cycloid scales (teleost fishes)
-Ctenoid scales (teleost fishes)
What is the ancestral scale form?
Having placoid scales
Atrium
top chamber of the heart
ventricle
bottom chamber of the heart
Heterocercal
asymmetrical tail
Homocercal
Having a symmetrical tail
Diphycercal
having a symmetrical tail but it also comes to a point
Placoid scales
each scale has little tiny spines that give it a sand paper feel
Ganoid scales
diamond like scales
Cycloid scales
overlapping circular scales
Ctenoid scales
circular/square shape with little spines at the end
Biphydont teeth
Type of teeth humans have; having two sets of teeth
What is one specialized sensory characteristics of Chondrichthyes?
They have neuromast cells that are found in the lateral line that act as mechanoreceptors and detect movement in the water
What is a second specialized sensory characteristics of sharks?
They have ampullae of lorenzini which are sensory cells that are sensitive to electrical potentials and detect prey, which gives off a weak magnetic field.
Are the 2 final specialized sensory characteristics of sharks?
-They have chemoreception which aids in their amazing smell and can detect 1 part per 10 billion - hammer heads specifically have stereo smell and really good vision.
How does the mechanoreception and electroreception work in sharks?
They have jelly filled canals that are concentrated in the rostrum that are electroreceptive; electrical pulses are then passed onto a bundle of nerves (known as ampullae of larenzini) that sits at the base of these canals.
What is the main differences between Holocephali and elasmobranchii?
Holocephali are includes the ratfish and rays and have 4 gill slits opening.
Elasmobranchii includes the sharks and has 5-7 fill slits.
What are holocephali also called?
Chimaeras
What are the characteristics of holocephali?
-Know as rabbitfish, ratfish, spookfish, ghostfish (25 species)
- remnants left of a line that diverged from the shark lineage during the devonian era (300 mya)
-Have jaws that bear large flat plates, upper jaw is fused to cranium, and have a grinding dentition (bottom jaw)
-Have bizarre shapes and are not well understood, rarely caught but are beautifully colored and iridescent
What are the major differences between skates and rays?
-Skates have an elongated but thick tail stalk that supports two dorsal finds and a terminal caudal fin, they are also oviparous.
- Rays have a whiplike tail, and its fins are replaced with one or more enlarged, serrated, and venomous dorsal barbs; viviparous.
Differences between skates and rays simplified
1) Rays are normally larger
2) Skates are oviparous while rays are viviparous
3) Skates have a thick and long tail stalk while rays have a whiplike and venomous tail.
What is the fourth class under vertebrata?
Osteichthyes (have bone)
What are the subclasses to osteichthyes?
Actinopyterygii (ray finned) and Sarcopterygii (lobe fins)
What are the characteristics of Actinopterygii?
-Known as the ray finned fish
-adapted to radiation in Devonian age (age of the fish)
-Includes 27,000 species
-Have a bony skeleton
-Have a homocercal tail
-Have ganoid scales in ancestral forms and cycloid or ctenoid scales in derived forms
-Have pairs fins that are supported by lepidotrichia (sharp ray like bones in fins).
What the Devonian era known form?
Was 300 mya and is known as the age of the fish.
What are lepidotrichia and what is its purpose?
They are sharp ray-like bones in the fins that provide structure and protection.
What are the operculum?
Boney covers over the gills of fish
What are some basic external anatomy features of Actinopterygii?
-Lateral line
-Dorsal fin
-Caudal fin
-Anal fin
-pectoral fin
-pelvic fin
-gills
-operculum
How does respiration occur in Actinopterygii?
Respiration is accomplished through their gills. The gills have a counter-current exchange system that allows respiration to occur.
Explain the purpose of the swim bladder in Actinopterygii
It aids in the buoyancy in fishes.
In chondrichthyes they have large oily livers with vacuoles in the liver cells that increase pressure and allows for movement in the water column
In actinopterygii, they have gas bladders that adjust with water and aid in movement in the water column.
Sarcopterygii
Commonly known as the lobe-finned fish
What are some characteristics of sarcoptergii?
-They had morphological characteristics that were superficially similar to amphibians
-There are 8 extant species within 2 orders
-They have a diphycercal tail
-Fertilization can be external or internal
-The big change: was the beginning of the evolution of lungs.
What order are the lungfish in?
The Dipnoi order. This class is closest to amphibians
What are some species of lungfish?
-Australian lungfish
-African lungfish
-South American Lungfish
Australian lungfish
Are the ancestral forms and had one lung, were aquatic, and rely on gills but can use lung as a backup.
-They swim by slow body undulations or through “walking” with fins and similar to early amphibians
-Use single lung when stressed
African (Protopterus) and South American Lungfish (Lepidosiren paradoxa)
-Have tiny gills and rely more on their lungs.
-Can drown if they are prevented from using its paired lungs
-Highly mobile paired appendages
-Undergo estivation (African lungfish)
-First time we begin to see a true transition from living in the sea to life on land.
Estivation
Ways that an organism accomplishes torpor by avoiding dry, hot weather
Torpor
Reducing your metabolic rate and decreasing your energy demands
