Beijing time on November 6th, according tomedia reports, from small to large, we may have asked parents and teachers “where did the children come from” such questions. While most of the answers they give may be absurd, biology classes in schools generally make things clear.
Humans have more straightforward ways of giving birth, but animals are much more complex (and much more interesting). Most wild animals need to reproduce, but many species do not need to mate to have children. This phenomenon is called monosexual reproduction.
What is single-sex reproduction?
Pictured is the process of sexual reproduction and asexual reproduction.
The breeding methods of animals are divided into sexual reproduction and asexual reproduction. When sexual reproduction is used, male and female organisms can produce genetically unique offspring. In this case, eggs and sperm are indispensable because they carry the genetic information needed to produce offspring.
Asexual reproduction, on the other hand, produces new individuals without the binding of a match. In the use of asexual reproduction, biological offspring are developed from the eggs of a single mother. The genes of the offspring of sexual reproduction may vary greatly, but the offspring of asexual reproduction are identical to between the mother.
Single-sex reproduction is a kind of asexual reproduction. Monogenic organisms supplement their genes with sperm used in sexual reproduction. The new individual is developed from an unseminized egg with exactly the same genes as the mother.
Creatures that can reproduce can either be “co-sexual”, i.e. can switch between sexual and monosexual reproduction, or “specialized”, i.e. unable to reproduce sexually.
There are more than 80 known species of fish, reptiles and amphibians that can reproduce monosexuly. These species rely on both male reproduction for reproduction only in extreme cases, such as when females and males are isolated from each other.
Let’s take some examples of different types of single-sex reproductive species.
Komodo giant lizard
To tell you the truth, who would have thought that the world’s largest lizard could reproduce through monosexual reproduction? But it is! In 2006, a female Komodo lizard at Chester Zoo in the UK gave birth to 25 eggs, but it has never mated with, or even shared, a room with a male Komodo giant lizard before.
Komodo lizards need to rely on monoxual reproduction to survive and reproduce.
Uniquely, a female lizard that breeds in a garden at London Zoo has laid four eggs, two and a half years after it last had sex with males. After mating with the male giant lizard, the female lizard gave birth to another nest of eggs, indicating that the Komodo lizard followed a part-sex monolithic reproduction.
Komodo lizards are found only in parts of the world and face a serious threat of poaching. As a result, their population composition is always distorted, either with fewer males, more females, or vice versa. These female lizards appear to have been forced to adopt monosexual reproduction due to a lack of male lizards.
In 2013, Australian scientists studied the life course of the bamboo worm. They found that female bamboo throbbs avoid mating with males in three ways: kicking their legs, or changing Fallomon, a odor molecule used by organisms for communication, to hide their whereabouts, or secreting lust-reducing chemicals to keep male bamboo-throbs away.
The study concluded that in some cases, it is beneficial not to pair female bamboo thybus. The researchers speculate that this may have led to the evolution of the species’ sexual monoxual reproductive capacity.
Copper-headed 蝮 snake
Several snakes can also reproduce through monogamous reproduction. A copper-headed snake 蝮 in Indiana gave birth to a small, stillborn snake and four un fertilized eggs. The snake was captured from the wild and reforested in captive, and has not mated for nine years.
Can you imagine a snake having children without mating?
Shahara whip-tailed lizard
As can be seen from the name, the lizard lives in the desert and grassland ecosystem of the United States. What makes the species unique is that it is made up entirely of females. As a result, they can only reproduce through monoxual reproduction. They reproduce by subtracting, and since all chromosomes of offspring come from the mother, all offspring are identical to the mother and are female.
The species also sometimes exhibits male-like behavior, which “pretends to mate” with other females and promotes reproduction.
The main advantage of the species’ use of monosexual reproduction is that they reproduce much faster than sexually reproductive species and can achieve rapid population growth under ideal conditions.
Australian scientists studying leopard-print sharks have found that the species can switch from sexual reproduction to monosexual reproduction in an artificial captive environment.
In 1999, researchers placed a female leopard-print shark caught in the wild with a captive male leopard-print shark. During this time, they mated first and then separated by researchers. Since then, they have been reunited and separated several times, until 2012, when researchers completely separated them. After stopping mating, the female leopard-print shark stopped spawning.
In 2013, researchers placed the female shark in the same pool as its daughter. Interestingly, during this time, the female shark actually began to lay eggs again. But what’s even more surprising is that its mature daughter, though never mating with a male shark, has started spawning!
The researchers believe the female shark’s eggs develop embryos either because the male shark’s sperm can be preserved in its body for a long time or because it can reproduce mono sex. The female shark’s daughter is likely to have had monosexual reproduction because it has never mated.
Most single-sex reproduction is observed in artificial feeding environments, such as aquariums and zoos.
There are several reasons why animals choose to have monosexual reproduction. First of all, single-sex reproduction completely avoids the cost of sexual reproduction, males do not need any input, do not need to pay courtship, for animals is very time-saving and labor-saving.
Second, single-sex reproduction can help species such as komodo lizards grow on uninhabited islands, allowing them to breed an entire population with just one female lizard. Finally, for many reptiles, insects and amphibians living in harsh environments such as deserts, there may be only one way to reproduce.
However, species of single-sex reproduction are often seen as entering a “dead end”, as offspring are completely mother clones, do not combine their sexuality, are unable to adapt to changing environments, are more susceptible to disease, and their populations are therefore seriously threatened and vulnerable to sharp decline. (Leaves)