The so-called natural selection, survival of the fittest. Nature has been working on its survival of the fittest.
In order to avoid the pursuit of predators, animals can be said to have evolved a variety of skills.
For example, when a gecko is frightened, as soon as it touches it, its tail will immediately break off, and the gecko will take the opportunity to escape.
This phenomenon is called "self-cutting" in zoology.
Because there are many nerves in the broken tail, after it leaves the body, the nerves do not lose their role immediately, so they will swing and play a frightening role to achieve the purpose of protecting themselves.
Tips1; The phenomenon of "severed limbs and self-help" often occurs in nature, in addition to geckos, lizards, this phenomenon is also more common in the diptera macroptera insects.
For example, chameleons' skin color changes with background, temperature, and mood, male chameleons turn dark protective colors into bright colors to warn other chameleons to leave their territory; some chameleons will turn calm green to red to intimidate enemies and protect themselves from attack.
Sea cucumbers are even more powerful, they will spit out a lot of white sticky strips when they encounter danger or enemies, which are the internal organs of sea cucumbers. As long as it is frightened, the sea cucumber will throw away the intestines, liver and a large amount of body fluid in the body, which can not only confuse and intimidate the enemy, but also reduce its own weight. When the internal organs erupt, a recoil is created that helps the sea cucumber to escape quickly.
Tips 2: The regenerative ability of sea cucumber is very strong, if the flesh of the sea cucumber is removed, after 5 to 7 days, small bumps will regenerate in the excised part, and these small bumps can grow to 1 to 2 mm after 30 days.
<h1 class="pgc-h-arrow-right" data-track="46" > animals that eat their brains</h1>
There is an animal that does the opposite, and does not take the usual path.
Not only do they eat their brains, they also turn themselves into "plants" and eventually become food on the table. It is "reverse evolution" – the sea squirt.
Friends who live in coastal areas or like to eat seafood should be familiar with the delicacy of sea squirt.
Sea squirts are also known as "sea pineapples" and "sea pineapples", and some coastal areas in the north will also call them "sea tits". It is not only delicious but also nutritious, and is loved by people.
The newly born sea squirt looks like a small tadpole. At that time, their bodies had various organs inside, the digestive system and brain were online, and they could move freely.
Tips3: Sea squirts like cold environments, widely distributed in the world's cold or temperate major oceans, is a very common marine life, the world has about 3,000 kinds of sea squirts.
<h1 class="pgc-h-arrow-right" data-track="24" > the sea squirt has a chord with a chord with a chordate. </h1>
First, let's popularize what is a chordate.
The Chordate Phylum is the highest class in the animal kingdom and the most successfully developed class.
Its common feature is that it has a chord, dorsal neural tube and gill fissure throughout or at a certain stage of its ontology, which are also the three characteristics of chordates.
Chordates include caudates, cephalic cords, and vertebrates.
Tips4: The lowest surviving chordates, such as sea squirts, Wenchang fish, etc., have not yet found their fossil ancestors because they do not have hard bones in their bodies.
The sea squirt mentioned above belongs to the tail cord of the chordate, and we humans belong to the vertebrates.
Thinking about it this way, the sea squirt and humans seem to have something to do with each other.
It has even been pointed out that humans and sea squirts once shared a common ancestor.
But in terms of current evolution, the ranks of humans and sea squirts are much different.
After all, among chordates, tail cords belong to the lowest class.
Although the sea squirt has a tail cord, the tail cord of the sea squirt can only be stored for a short time. Because the newborn sea squirt needs to swim to a safe place within 12 hours, after finding the location, it will be used as an "old nest" and will not move here since then.
After landing on the ground, the sea squirt began to carry out its "retrograde metamorphosis".
tips5: Tails are the lowest chordates and are evolutionarily related to higher chordates, both of which may have evolved from a common ancestor of a sea squirt larval-type camp that lived freely, primitive headless animals.
<h1 class="pgc-h-arrow-right" data-track="49" > what is retrograde metamorphosis</h1>
The so-called "retrograde perversion", in simple terms, is to lose some important structures and make their own form simpler.
At this time, sea squirts will first discard their tail cords, which are one of the symbols of animals, and then they will degenerate the nerve cords into ganglia, and then secrete from the body that belongs to the cellulose capsin to wrap the body, making itself look more like a plant.
After "metamorphosis", the sea squirt, which could still move freely in the sea, could only "waste time" like a plant on the seabed.
At this time, the sea squirt does not swim or feed, but constantly absorbs and drains water through its water outlet and water holes, absorbs oxygen in the water by the gills, and eats the plankton and organic matter in it by the intestine, thereby maintaining life.
Tips 6: Sea squirts cling to rocks and bottoms of boats all year round as adults, while sea squirts in the deep sea feed on plankton and in shallow seas feed on animal droppings and secretions.
This is not the most powerful, the "perversion" of the sea squirt is also that for the brains that are no longer useful and consume high energy, they will eat most of them directly as nutrients for development, leaving only a part of the brain to control the internal organs and breathing holes.
At this time, the sea squirt, which looks like an eggplant or a flower, and will remain motionless on the bottom of the ship or on the reef on the bottom of the sea for many years, which is no different from "plant".
However, there are also certain advantages to fixing yourself, for example, because it cannot move in place, it is not easy to attract attention, which allows the sea squirt to avoid the hunting of many predators.
However, there will still be some animals that feed on sea squirts.
Therefore, in the process of "retrograde metamorphosis" of sea squirts, they also retain a certain defense mechanism. It is to spray your own internal organs directly when you encounter danger.
Tips7: In addition to digesting its own brain, the sea squirt also includes other body parts: tail, primitive eyes, spinal cord (spinal structure), etc., and then secretes a plant-like fiber for camouflage.
In the early years, zoologists Shenkar and Gordon from Tel Aviv University in Israel studied a sea squirt called "Polycarpa mytiligera" and found that they could survive by spewing out internal organs, including the stomach, intestines and part of the rectum, like sea cucumbers.
Because many fish don't like offal, when the sea squirt sprays offal, most fish will avoid it with disgust.
Moreover, by spraying internal organs, it can also play a role in intimidating the enemy.
After several subsequent studies, the researchers found that 47 percent of the 66 sea squirt samples would eject viscera.
8 Each sea squirt does this after an average of 16 seconds, and the length of the ejected material is on average about an inch or half of the digestive tract of the sea squirt.
Such an important thing as internal organs, how to say don't want it? After all, for ordinary animals, the absence of internal organs is equivalent to death.
But sea squirts are special because their internal organs can be reborn. In about 12 days, the sea squirt can grow new internal organs.
Therefore, the powerful repair ability of sea squirts has also become the target of scientists' research. If the mystery can be solved, perhaps human medical technology will enter a new level.
In addition, the research value of sea squirts is also reflected in their "retrograde metamorphosis".
We all know that the evolution of most creatures in nature is in a higher direction. But this way of developing sea squirts is essentially a kind of degeneration.
9 Retrograde metamorphosis is a phenomenon in which chordates lose some of their structure and become simpler after metamorphosis, sometimes referred to as degenerative metamorphosis. Frogs are also a metamorphosed animal.
Although sea squirts are chordates, the morphological structure of adult sea squirts differs greatly from typical chordates. And they also changed their way of life, beginning to stick to rocks, making a living by filtering seawater and no longer roaming around.
The front of the body has a protrusion, the body has changed, the spinal cord has disappeared, some other important organs have also faded or atrophied, and also produced a sac, etc., and also exhausted their brains.
<h1 class="pgc-h-arrow-right" data-track="52" > hermaphrodite</h1>
Evolutionarily, it did not move forward but backwards, it changed from having a chord to not having an orochord, a phenomenon of "retrograde metamorphosis" that is rare in the animal kingdom, so the sea squirt has a very important value in studying and solving the problem of the origin of chordates.
10 Sea squirts have been alive on Earth for 500 million years, and their lifespan in the wild is 7 to 30 years, which shows that their "retrograde metamorphosis" way of living is reasonable.
In addition to transforming itself from an animal to a "plant", the sea squirt has another characteristic, that is, hermaphrodite.
The so-called hermaphrodite refers to the phenomenon that both female and male traits are obvious in an organism. Both animals and plants have hermaphrodites.
Atlantic scallops, for example, grow mainly along the coast of North America, and male flat shells roam underwater until they finally find a suitable mate. Then, it sneaks on the back of the female flat shell, and it is not long before the male flat shell loses its genitals and becomes a female flat shell. After that, another male flat shell will fall on its body and transform into a female.
There are dozens of hermaphrodite animals in nature, and they are divided into males and females, or females when males. Earthworms and snails are hermaphrodites, jellyfish, schistosomiasis and squid, etc., are hermaphrodites.
Snails we are familiar with are also hermaphrodites. The male reproductive organs of the snail have a small sac filled with snail eggs, which can fire thin bone missiles at any time. When two snails with a strong willingness to make friends hug each other, they will shoot arrows into each other's bodies and exchange sperm with each other.
In addition, barnacles, clean fish, earthworms, slugs, yellow eels, etc., are also common hermaphrodites.
Generally speaking, the more complex the structure of animals and the more advanced the evolution, the more distinct the characteristics of their divisions.
However, hermaphrodites are also present in humans, and the incidence rate is about 0.018%.
12 Usually, a person's sex is determined by the sex chromosome XY, with people with XX chromosomes developing into females and people with XY chromosomes developing as males. Hermaphrodites generally have both bisexual chromosomes at the chromosomal level, such as XXY.
As a hermaphrodite sea squirt, it can be both a father and a mother. That is, they can produce both sperm and eggs. However, they cannot reproduce by fertilizing themselves, because sperm and eggs have different times of maturation, and they must have another sea squirt to reproduce with them.
<h1 class="pgc-h-arrow-right" data-track="55" > the reproduction of sea squirts</h1>
Of course, if there is really no object that can be reproduced, the mature sea squirt can also work hard to reproduce asexually.
At this time, they will grow a small sea squirt in a "germinated" manner, like branches of branches. After the small sea squirt attaches to the mother and matures, it can break away from the mother and become an independent individual.
It is worth mentioning that the new sea squirts produced through asexual reproduction do not have the ability of the mother to reproduce asexually. Sexual reproduction is necessary to derive the next generation.
Tips: Asexual reproduction does not involve germ cells, does not need to go through the fertilization process, and directly forms new individuals from a part of the mother' body. Asexual reproduction is more common in the biological world, and there are many forms such as split reproduction, budding reproduction, spore reproduction, and vegetative reproduction.
Despite certain limitations in asexual reproduction, sea squirts quickly spread around the globe with their own special breeding methods
And found by humans as food.
When it comes to sea squirts being found as food, there are some more stories.
< h1 class="pgc-h-arrow-right" data-track="60" sea squirts > found</h1>
Because some sea squirts will attach to the hull, increase the bottom protrusion of the hull, reduce the streamline of the hull, resulting in a decrease in speed and fuel consumption, so in the eyes of seafarers, sea squirts are not popular.
And, because the shape of the sea squirt is a little strange, at first, humans even felt that it was a harmful sea creature.
But later, people suddenly found that this fat seafood that looked like pineapple had a refreshing and sweet taste, and the taste was quite good.
Tips: There are many colors of sea squirts, which can be green, yellow, red, orange, pink, blue, brown or white, raw sea squirts, sweet taste, accompanied by bitter taste, and fishy taste is relatively heavy.
In addition to being delicious, the nutritional value of sea squirts is also very high. Tests have found that the sea squirt contains 19 kinds of amino acids, including 8 kinds of essential amino acids. Although the content of sea squirt protein and amino acids is not high compared with freshwater fish and some marine organisms, its content of bovine acid is very rich, reaching 20.20mg per 100g.
Moreover, sea squirts contain at least 6 fatty acids, of which 5 are unsaturated fatty acids, and the EPA+DHA is higher than that of freshwater fish, marine fish and other marine organisms.
Because DHA and EPA are among the more precious nutrients, you can see that this ingredient is added to many baby milk powders.
They help regulate the body's endocrine, promote blood circulation, and can also improve the body's immunity. Appropriate supplementation of DHA and EPA has a certain help to reduce cholesterol, in addition, these two components can also avoid the formation of thrombosis and arteriosclerosis, and have a certain protective effect on the body's blood vessels.
Tips: Sea squirt is rich in unsaturated fatty acids, and studies have found that some sea squirin-soluble extracts have certain hypolipidemic activities, which is also a new resource for lipid-lowering natural medicines or functional foods, with good development and utilization potential.
Therefore, the sea squirt was not only quickly served on the table, but also made into a health food to balance the nutrition of the human body.
Now we can find the shadow of the sea squirt in the world's oceans, from the tides to the deep sea below a kilometer.
Because sea squirts love cold, the main areas of survival are in the cold or temperate zone, and the tropical areas are fewer and smaller.
There are only one or two edible sea squirts, which are cultivated in large areas in Miyagi and Iwate prefectures in Japan.
The season is from June to August every year, and it is called "Tohoku Treasure".
<h1 class="pgc-h-arrow-right" data-track="57" > conclusion</h1>
Tips: The most common food in Korea is sea squirt bibimbap and sea squirt sashimi, which are cut open like passion fruit, which is yellow inside and eats the yellow part.
It should be added here that although the distribution of sea squirts is relatively wide, it is still relatively rare due to the short production of the season. Therefore, only in Japan, South Korea, and France, there are more ingredients to eat, which is relatively rare in China, and if you can eat it, it is also a kind of luck.
I have to say that the sea squirt really paid too much to change from animal to "plant". Not only did most of the brain be sacrificed, but the nerve cord was also degenerated. However, it may not have been expected that it would eventually become food on people's tables.
However, they should not think much about it, after all, their brains are gone.