Med Aka

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The Life of Glenn the Japanese Medaka By: Jordan McGee and Hannah Smith Period 5

Stage 2 • We received our eggs on April 6. • The egg is fertilized. The yolk is

yellowish in color and transparent.

Stage 17 • The central nervous system is starting to occur.

Stage 18 • The anterior end of the keel has

broadened into two divisions of the rudimentary brain.

Stage 19 • The tail is termination and the rudimentary optic vesicle has formed.

Stage 21 • Pericardial cavity and optic cup. The primary rain divisions are distinguishable.

Stage 22 • The optic lens starts to become

clearer, and the brain ventricals are forming.

Stage 23 • The heartbeat pulsates 40 to 60 beats per minute.

Stage 27 • The pectoral fin bud and blood circulation is strong.

Stage 28 • There is pink blood visible, the

most is in the heart, and the beats per minute is 120.

Stage 30 • The urinary bladder is developed

and the blood is a darker pink. The eats per minute is 140.

Stage 32 • The liver rudiment is developed.

Also the cornea of the eye may be raised slightly off of the lens.

Stage 33 • The swim bladder is formed. The rudiments of several internal organs have developed by the sixth day.

Stage 35 • The spleen and mouth are formed.

The spleen arises as a small crimson colored rudiment between the urinary and swim bladders.

Stage 36 • The medaka hatches. • Our medaka hatched on April 27.

Life Before Hatching • When you first get the eggs, you

have to change the water that they lay in everyday. We received our egg on April 16 and changed the water everyday.

Life After Hatching • After the egg has hatched and you

look at it, you have to transfer it to a tank with spring water. You need to feed them turtle food. Our egg hatched on April 27.

Filament and Chorion • The filament is a long chain of

protein subunits such as those found in hair or muscle.

• The chorion is the external layer of the egg that protects it during development.

Cytoplasm and Yolk Sac • The yolk sac is the sac of fluid that

the baby eats while it is developing and growing.

• The cytoplasm is the part of the cell that is enclosed within the plasma membrane.

Oil Globule and Heart • Oil Globule helps nourish the fish while it is developing.

• The heart is the organ that is

responsible for pumping the blood through the blood vessels.

Fin • Pectoral- is located on either sid

usually just behind the operculum.

• Caudal- this is the tail fin. • Dorsal- this helps the fish make

sudden turns, and keeps the fish stabilized.

Optic cup/eye and the brain • The brain is what controls all of the movements of the fish and how it reacts.

• The optic cup is the part that holds

the eye into the fishes head, and the eye is used to help the fish see.

Somites and Mouth/Jaw • Somites are the divisions of the body.

• The mouth and jaw are used to eat the food.

Resources • Japanese Medaka book • wikipedia.com/japanesemedaka