Black Sea Nettle is a common name for this species of jellyfish however it is scientifically know under the name of Chrysaora achlyos. This name was created using the organism's Genus and Species classifications. There are five other levels of Taxonomy in the list below that separate the Black Sea Nettle from nearly all other life on Earth.
Level of Taxonomy and Classification
- Kingdom: Animalia
- Phylum: Cnidaria
- Class: Scyphozoa
- Order: Semaeostomeae
- Family: Pelagiidae
- Genus: Chrysaora
- Species: achlyos
All of these species of jellyfish can be found in the same family as the Black Sea Nettle which is the third most specific taxonomic level. Since all of these jellyfish are closely related, they have many common characteristics.
These Characteristics Include:
- These jellyfish do not have a ring canal, which is an anatomical feature near the center of the jellyfish that many other jellyfish have.
- Their tentacles come from clefts or small indentations between lappets (sensory structure) on the outside edge of the jellyfish.
- They have long oral arms that are pointed and folded and ruffled.
- Jellyfish in this family also have a painful poisonous sting.
Black Sea Nettle Diagram
The evolution of jellyfish including the Black Sea Nettle remains mostly a mystery. This is because the soft tissue of jellyfish decomposes so quickly that remains are almost never captured by fossilization.
There are very few pressures on Black Sea Nettle or other jellyfish to adapt. Actually, many problems that are negatively affecting other ocean species are having a positive impact on jellyfish species. This has lead to the potential overpopulation and expansion of jellyfish.
Global warming is slowly warming oceans. This is allowing jellyfish that prefer warmer waters to spread towards both poles away from the equator. Black Sea Nettle prefer moderate temperatures and this allows them to expand farther north along the North American coastline.
Global warming also targets predators of Black Sea Nettle including sharks, sea turtles and some large species of fish.
Fertilizers and nutrients from farms eventually end up in the ocean. Some plankton thrive on these nutrients. Jellyfish then have a constant food source and can also thrive.
Other than contributing to global warming and fertilizers in the ocean, humans also over fish predators. This problem alternates the food chain and puts the Black Sea Nettle on the top of the food chain. This is a problem because this species reproduces very quickly and with few natural predators, more of them would reach maturity. This would overpopulate the oceans with jellyfish.
First, male jellyfish (XY sex chromosomes) produce sperm in their gonads. Likewise females (XX sex chromosomes) produce eggs in their gonads. The males release the sperm into the water. As the females swim through the water, the eggs attached on the upper oral arms are fertilized.
They attach to the surface and develop into "polyps." One end attaches to the surface and the other end that has tentacles draws food in.
After the polyp becomes more mature, which may take years, polyps can asexually reproduce and split off into more polyps. Polyps will also start to develop horizontal lines around the stalk that eventually will become a stack of saucers.
Each saucer will develop into a baby jellyfish called an "ephyrae". About 5 to 15 ephyrae will come from the polyp. This is another example of asexual reproduction.
These ephyrae quickly develop into the popular form of jellyfish, the "medusa". The medusa is sexually mature after a few months and only lives for about 6 months to a year.
The Black Sea Nettle may have anywhere from 44 to 216 chromosomes (the actual number was not found). These chromosomes are comprised of DNA and are diploid. This means that every chromosome is paired with another that contains identical data.
There are no know genetic disorders that affect jellyfish.
*Note that these alleles were created and may not reflect scientific evidence*
Black Sea Nettle that are dark red have the dominant trait for coloration (C). Black Sea Nettle that are dark purple have the recessive trait for coloration (c).
Large Black Sea Nettle are homozygous with the (Sᶫ) allele. Small Black Sea Nettle are homozygous with the (Sˢ) allele. Medium sized jellyfish are heterozygous with both the (Sᶫ) and (Sˢ) allele.
A heterozygous dark red and large sized male mates with a heterozygous dark red and small female. What are the possible phenotypes and genotypes of their children?
The male is (CcSᶫSᶫ) with a possibility of CSᶫ or cSᶫ.
The female is (CcSˢSˢ) with a possibility of CSˢ or cSˢ.
This shows that 100% of the offspring will be medium sized. Also, the offspring will have a 75% chance of being dark red while having a 25% chance of being dark purple. The genotypes of the offspring can be described as a 1:2:1 ratio
- 1: homozygous dark red, heterozygous medium size
- 2: heterozygous dark red, heterozygous medium size
- 1: homozygous dark purple, heterozygous medium size
All jellyfish, including the Black Sea Nettle have a simple digestive system. This means that nutrients are obtained and excreted in the same opening.
The mouth and anus opening can be found in the center at the bottom of the medusa. This opening leads to the gastrovascular cavity in the very center of the jellyfish. It is lined with the gastrodermis which is only one or two cells thick. Some enzymes help break down the food while the gastrodermis absorbs nutrients. Waste is expelled quickly out of the mouth and anus opening so the jellyfish is not weighed down.
Jellyfish are all carnivores and often attempt to eat anything that crosses their paths. They are 95% water and require very little energy. They do not have a brain or any other major energy requiring organs. Also, their movements are incredibly efficient even though they usually flow with ocean currents anyways.
The Black Sea Nettle requires some protein as well as lipids and carbohydrates. It is unknown if jellyfish are using vitamins and minerals from the food they consume.
There are few limitations to the Black Sea Nettle's food source. Zooplankton are extremely common and the jellyfish are able and willing to consume nearly any prey that it comes in contact with. However, if the jellyfish are not consuming enough nutrients, it can stop moving and flow with the ocean currents if necessary.
Jellyfish have a unique and effective way to capturing prey. They use their tentacles and water currents to catch their prey.
Their tentacles are covered in nematocysts which are tiny stinging barbs that shoot out and inject a neurotoxin that paralyzes it's prey. The oral arms then direct the prey through the mouth.
When jellyfish open and contract their bell, they create water currents that direct prey towards their tentacles and plankton towards their mouth. So, the Black Sea Nettle passively collects zooplankton.
This is an effective and efficient system. The jellyfish does not have to spend any energy chasing prey. With the water currents, prey comes directly to the jellyfish. Also, because of the tentacles, the jellyfish does not need to spend energy fighting with it's prey. Jellyfish do not need to see, hear, smell or taste their prey and only need to feel their prey.
Jellyfish actually do not have a circulatory system or any blood. Instead nutrients and oxygen diffuse into the jellyfish. Diffusion occurs when an area of higher concentration spreads into an area of lower concentration. In this case, the oxygen and nutrients travel from the water and through cells into the jellyfish.
The skin of jellyfish, including the gastrovascular cavity, is only a few cells thick. This contributes to the transparency of most species. So, this allows simple diffusion of the nutrients and oxygen into the jellyfish. From there, the oxygen and nutrients continue to diffuse into the neighboring cells.
Osmosis is a process that moves a solvent (water) through cells. The water in the jellyfish have the same concentration of solute (dissolved substance) as the water around them.
This system is beneficial to the Black Sea Nettle because oxygen and nutrients can move around it's entire body without wasting energy or needing another circulation system. It's important to note that this is only possible due to thin body tissues and lack of muscle mass and other tissues, as these tissues would require higher levels of oxygen and nutrients.
Little is known about the immune system of jellyfish.