CATDOLL : CATDOLL: How do siphonophores reproduce?

1. How do siphonophores reproduce?

The complex tube jellyfish contains four basic jellyfish bodies: swimming body, floating body, protective body, and reproductive body. The reproductive body can split into asexual reproduction buds. The buds of a few jellyfish can float independently in the sea, but they can neither prey nor live long, and they die once they release sperm and eggs. However, the buds of most tube jellyfish do not separate from the mother body, but attach to the mother body to release sperm and eggs, just like reproductive organs.

Siphonophores reproduce asexually! They divide themselves

How can low-level jellyfish reproduce by scratching themselves? How can they compare to the elegant Butterfield jellyfish and Diffie jellyfish, which have more than 800 reproductive postures?

Jellyfish are dioecious, with reproductive glands near the stomach sac. Mature sperm flow into the female jellyfish for fertilization. The fertilized eggs develop into larvae and leave the mother's body. After swimming in the water for a while, they sink to the bottom of the sea to form larvae, which later become polyps. The polyps split into multiple disc-shaped larvae, and then develop into adult jellyfish. Although jellyfish are low-level coelenterates, they have three generations living under the same roof, which is enviable. Jellyfish give birth to baby jellyfish. Although the baby jellyfish can survive independently, the parent-child relationship seems to be deep and they can't bear to be separated, so the baby jellyfish all cling to the jellyfish's body. Soon after, the baby jellyfish gave birth to grandchildren of jellyfish, and they are still closely connected.

2. Can the eggs laid by jellyfish in the jellyfish tank be hatched?

Jellyfish eggs are shown in the picture: Jellyfish, represented by the moon jellyfish, mainly go through generations. In the water, sperm and eggs combine to produce free-swimming planula larvae. Planula larvae attach to stone walls or corals and grow into polyps. The upper end of the polyp is hollow and cylindrical, with tentacles around the mouth and nematocysts on the tentacles. The tentacles capture and send food into the mouth. The lower end of the polyp is used for fixation. The polyp undergoes fission reproduction (asexual reproduction) and gradually grows to form a transverse body, releasing jellyfish larvae at the top. The jellyfish larvae eventually grow into a medusae body, and some medusae reproduce sexually. However, not all jellyfish have the above generations. For example, the Anthozoa class of cnidarians only has polyps. Some jellyfish do not have jellyfish larvae. The Turritopsis dohrnii can revert from a medusae body to a polyp in dangerous situations, and can repeat indefinitely. Jellyfish are dioecious, with gonads near the stomach sac. The mature sperm flows into the female jellyfish for fertilization. The fertilized eggs develop into larvae and leave the mother's body. After swimming in the water for a while, they sink to the bottom of the sea to form larvae, and then become polyps. The polyps split into multiple disc-shaped larvae, and then develop into adult jellyfish. Although jellyfish are low-level coelenterates, they have three generations living together, which is enviable. Jellyfish give birth to baby jellyfish. Although the baby jellyfish can survive independently, the parent-child relationship seems to be deep and they can't bear to be separated, so the baby jellyfish all cling to the jellyfish's body. Soon after, the baby jellyfish gave birth to grandchildren of jellyfish, and they are still closely connected.

3. How to hatch the magical jellyfish bought at the store?

It is probably brine shrimp or other microorganisms, the possibility of jellyfish is basically zero. Look at the instructions and try it according to the instructions.

4. How do jellyfish grow?

The jellyfish umbrella is colorless and transparent, disc-shaped, with a diameter of about 10 to 30 cm, and 98% of the body is water. When floating, the outer umbrella is upward and the lower umbrella is downward. There are 8 nodule-like structures on the edge of the umbrella, each with a sensory organ, and a hollow tentacle sac in each sensory organ, with a balance stone at the end of the sac. Many tentacles are suspended on the edge of the umbrella between every two nodules. There is a square mouth in the center of the lower umbrella, and a drooping oral arm at each of the four corners of the mouth. The four horseshoe-shaped reproductive glands are pink.

They are distributed in all oceans of the world. In my country, groups of moon jellyfish can be found along the coast of Yantai, Shandong Province in July and August.

【Biological characteristics】

There are many stinging cells on the oral arms, which can release stinging threads to paralyze small invertebrates, and then swallow them into the mouth and enter the stomach through the oral canal. The stomach is relatively large and protrudes to form four stomach sacs. After the food is digested, it is transported to the whole body by the radial tubes, and the indigestible residues are still discharged from the mouth. Breathing and excretion are both carried out on the body surface that is in contact with water.

【Life History】

There is a typical alternation of generations in the life history. The moon jellyfish is dioecious and similar in appearance. Sperm swims out of the mouth, enters the digestive cavity of the female body and fuses with the egg to form a zygote. The zygote attaches to the oral arm and develops into a floating larva with many cilia. After a period of floating, the cilia fall off and sink, attaching to objects on the seabed, becoming a polyp-type larva or a scyphistoma with a mouth and tentacles. Later, it uses transverse fission to produce a disc-shaped larva (ephyra). Each disc-shaped larva, after turning over, finally develops into a free-living moon jellyfish. Some can directly develop from polyp-shaped larvae to adults without complex metamorphosis.

【Living conditions】

The optimum temperature is 22-26 degrees, the upper limit is 30 degrees, and the lower limit is 15 degrees. The optimum salinity range is 28-32. The lower limit of salinity is 25, and the upper limit is 38. Tolerant to ammonia nitrogen and nitrite nitrogen, the upper limit is 2 mg/L, the better the water quality, the stronger the vitality

5. Do jellyfish give birth?

Jellyfish have many different forms and stages of function during their growth and development, a phenomenon called polymorphism. Sometimes, these forms can lead scientists to mistake different stages of a jellyfish for new species.

Generally, jellyfish go through four different stages: the vegetative body with tentacles that can hunt; the finger-like body without mouth and tentacles, with a large number of stinging cells on the top of the individual body for protection; the stinging body with bone spurs in the epidermis that have support and protection functions; and the last one is the reproductive body. The reproductive body has jellyfish buds, but they are not released from the group to swim freely. Instead, the jellyfish buds produce sperm or eggs that are fertilized in the seawater.