BIO 204 Lab Practical 6

Lab 11: FIshes

Notocord

Rod shaped structure that supports the back in vertebrates, it later develops into the spine or vetebral column

Dorsal hollow nerve cord

Bundle of fibers running down the back that becomes the central nervous system in vertebrates

Pharyngeal bars and slits

Openings that connect the side of the throat to the outside of the neck, often used for filter feeding or as gills.

Endostyle

Structure of the throat [e.d thyroid] that helps regulate metabolism and iodine uptake

Post anal tail

Muscular extention of the body that reaches past the anal opening

What is a tripartate brain and why is this and evolutionary advantage?

Three divisions of the brain; larger brain—> increased ability to process responses to the environment; possibly related to evolution of more complex sensory organs

What is a ‘lateral line system’ and what organisms is it present in?…

Receptors in the skin that sense vibrations and changes in water pressure.

What are two functions of the pineal organ?

Perceive environmental light changes, melatonic secretion to regulate behavioral rhythms

What are the two heart chambers evolutionary significance?

There is one atrium and one ventricle; evolved with increased capillaries, increased respiratory efficiency because muscle is required to pump blood more efficiently to many tiny capillaries

What is the main function of the liver?

Protein + fats—> charbodydrate metabolsim

What is the main function of the kidney?

Waste removal, maintaining solute equilibrium

What is hemoglobin?

Hemoglobin is a repiratory pigment which increases blood oxygen content by binding with oxygen in the blood

Why do vertebrates have both hemoglobin and myoglobin?

• Hemoglobin: Transports oxygen through the bloodstream from respiratory organs to tissues.

• Myoglobin: Stores oxygen directly inside muscle cells and has a higher affinity for oxygen allowing it to efficiently "pull" oxygen out of the blood for immediate cellular use.

What might high myoglobin content say about the ecology of a vertebrate?

Myoglobin content indicates that a verterbrate is evolved for a highly athletic, endurance-based, or deep-diving lifestyle requiring sustained aerobic metabolsim

Myxini; [Hagflish]

Jawless, mostly marine, produce mucus in defense

Petromyzontida: [Lapreys]

Many parasitic taxa, rasping toungue, are anadromous

What does anadromous mean?

Migration from ocean to freshwater to reproduce, then juvenilles swim to the ocean

Gnathostomata (jawed vertebrates) apomorphies

jaws, calcified teeth, paired fins, muscular stomach, pancreas, spleen

Who belongs to the group of Chondrchthyes [cartilaginous fish]

sharks, rays, skates, ratfishes

Chondrchthyes [cartilaginous fish] apomorphies

Placoid scales

Claspers (male reproductive organs)

Chondrchthyes [cartilaginous fish] features

Carnivorous, marine, cartilaginous skeleton

Osteichthyes [Bony fish] apomorohies

• Gas bladder: functions for boyancy control

• Operculum: hard bony flap that covers and draws water over gills

• Adenticulate scales

What are Actinopterygii?

Ray finned fishes

Homocercal vs heterocercal tail

Homocercal: asymmetrical; spine bends upward into a larger top lobe (produces thrust + lift, e.g sharks)

Heterocercal: symmetrical spine stops at the base; generates forward thrust in fish with swim bladders (bony fish)

Sarcopterygii: [Lobe-finned fish] apomorphies

• Muscular lobed pectoral and pelvic fins

• True enamel on teeth

Actinista apomorphy

• 3-lobed tail

• Only 2 extant species

Choanata: Dipnoi [Lungfish]

Breathe air for boyancy control

Chondrichthyes: Elasmobranchi apomorphies

1. Two fin species (dorsal fins)

2. Ampullae of Lorenzini ( tiny pores on snout;detects weak electrical fields from hidden prey; geomagnetic navigation)

3. Spiricals: water intake value for bottom dwellign fish can inhale water while their mouths are burries in sand

What does a heterocercal tail say about an organisms ecology?

Highly dynamic and versitile swimming ecology