Information

What makes animal to continually reproduce?


I was reading about Trypophobia and reached to Surinam Toad's reproduction methods. Then I had this doubt- Why would animals want to reproduce so much? In case of humans we mostly have the offsprings nearby for entire life, so some of them may take care of us. But in case of many other animals after birth they have no connection with their parents.

So why do they always try to reproduce in large quantities in entire life time? What they achieve in this?


Why organisms reproduce

If they didn't reproduce, they would die out.

More concretely, suppose an animal is born with a mutation that removes the desire to reproduce. That animal will not have any offspring, so its genes will not be passed on to the next generation. When that animal dies, that mutation will die with it.

Why some organisms reproduce a lot

Different animals or other organisms have differing strategies for reproduction, based on their ecology. Some animals, like the Surinam toad, try to have a lot of offspring with relatively little "investment" (of energy, time, effort, etc.) in each one. Many of the offspring will die, but enough will survive that the organism's genes can persist. Other animals, like elephants, only have a few offspring but spend a lot of effort in making sure those few offspring survive.

You can read more about this in the Wikipedia article on life history theory.


Scientists revived a tiny worm-like animal after 24,000 years frozen in Siberian ice. It was still able to eat and reproduce.

  • Scientists were able to revive a tiny-worm like organism found in 24,000 year old Siberian ice.
  • The worm was able to eat and reproduce after thawing.
  • The findings could provide clues into how to freeze multi-cellular tissues like organs.
  • See more stories on Insider’s business page.

Russian scientists have been able to revive a tiny animal called a Bdelloid rotifer that was found in Siberian ice dating back 24,000 years.

After thawing, the tiny worm-like organism was capable of eating when fed, as can be seen in the video below.

After thawing, the rotifer was also able to reproduce – which it can do without a partner, scientists said in the study.

It suggests that these multicellular animals are can survive in a kind of icy holding pattern for tens of thousands of years.

“We revived animals that saw woolly mammoths,” Stas Malavin from the Soil Cryology Laboratory in Russia, one of the authors of the study, told The New York Times.

The findings were published on Monday in the peer-reviewed journal Current Biology.

Rotifers are among the toughest animals in the world, Malavin told Insider in an email, known for their resistance to extreme environments. They are among the most radiation-resistant animals on Earth, and can endure extreme dehydration and low oxygen.

“If true, this would be an incredible result and extend the recorded ability of Bdelloid rotifers to survive freezing from 10 years to 30,000 years,” Timothy Barraclough, a Professor of Evolutionary Biology who works on rotifers from the University of Oxford, told Insider.

However, he warned that it possible that the animals colonized the ice later than 24,000 years ago, or after the ice core was removed from the ground.

“I need a bit more persuading,” he said.

These animals are not the oldest ever found to be able to survive freezing. In 2018, two parasitic worms known as nematodes were revived from ice that was at least 30,000 years old.

Understanding the biological mechanisms that drove the rotifers to survive such long periods of freezing could help scientists figure out how to better freeze tissues, such as human organs, a press release accompanying the study said.

The takeaway is that a multi cellular organism can be frozen and stored as such for thousands of years and then return back to life – a dream of many fiction writers,” Malavin said.


Animals that Regenerate

Many animals can regenerate-that is, regrow or grow new parts of their bodies to replace those that have been damaged. Here are a few of these amazing creatures.

Lizards who lose all or part of their tails can grow new ones. This is a good escape technique. A lost tail will continue to wiggle, which might distract the predator and give the lizard a chance to escape. Most lizards will have regrown their tail within nine months.

Planarians are flat worms. If cut into pieces, each piece can grow into a new worm.

Sea cucumbers have bodies that can grow to be three feet long. If cut into pieces, each one can become a new sea cucumber.

Sharks continually replace lost teeth. A shark may grow 24,000 teeth in a lifetime.

Spiders can regrow missing legs or parts of legs.

Sponges can be divided. In that case, the cells of the sponge will regrow and combine exactly as before.

Starfish that lose arms can grow new ones sometimes an entire animal can grow from a single lost arm.


Ready for Reproduction

Near the head of an earthworm is a smooth band called the clitellum. This band normally matches the color of the rest of the worm's body, but when earthworms are ready to mate, the band turns a darker shade. Although some species of earthworms will mate on the soil surface, this leaves them exposed to predators during this vulnerable time, so most worms mate underground. The worms are thought to find one another through the release of pheromones. Once a partner is found, the two worms line up in opposite directions so that each worm's male opening lines up with the other worm's sperm receptacle, known as the spermatheca. The worms are then in position to exchange sperm.


Genetic Engineering and Animals

Scientists are now capable of creating new species of animals by taking genetic material from one, or more, plants or animals, and genetically engineering them into the genes of another animal. This allows scientists to create animals that are on one hand completely foreign to the earth and on the other, specifically tailored to possess only the traits that humans desire in animals.

This means that science can engineer farm animals to grow faster, have healthier meat and flesh, and be less able to feel the pain and suffering often associated with the conditions present in modern factory farms. Genetically engineered animals are also created to help medical researchers in their quest to find cures for genetic disease, like breast cancer. Finally, endangered animal species can be cloned, thus helping wildlife management in its goals of preserving wild populations of the earth’s biological diversity, and by ensuring that endangered animals' genetic information will not be lost when the last of the species dies.

This use of modern technology is not without its drawbacks or its critics. By genetically engineering farm and research animals, critics argue, we may be undoing what nature has worked to create over millions of years. Natural animals are specifically adapted to a given environment and when science manipulates the genes of a few species in the ecosystem, the entire balance of the ecosystem might fall completely apart causing an unknown number of natural animal species to grow ever extinct. Others argue that animals should possess, at a bare minimum, the right to be free of genetic manipulation or a reduction in their natural abilities.

Despite this debate, the law in both the United States and in Europe, tends to support genetic engineering research and development by allowing genetically engineered animals to be patented. Patents give scientists a monopoly over their genetically engineered animal species, something before unheard of in modern economic systems. Typically, animals could be owned, but never entire species.

Regardless, we must not wait and see what the effects genetic engineering animals will have on the earth. We must form educated opinions, lobby for government regulation, and hope that whatever direction that bioengineering takes us, is a positive step towards decreased animal suffering, increased environmental sustainability, and an overall compassionate regard for the earth and its precious life.

Genetic Engineering and Animals: A Short Summary of the Legal Terrain and Ethical ImplicationsAndrew B. Perzigian (2003)

With the advent and rapid development of genetic engineering technology, the animal rights movement is currently facing one of its greatest challenges and dilemmas. Proponents of the technology assert that transgenic animals, animals that have been genetically altered through the introduction of another plant's or animal's genes, may one day help solve many of our modern day problems in life, from starvation and ill health, to environmental degradation and the modern extinction crisis. Critics believe that bioengineering poses greater risks than it does benefits. They argue that genetic engineering threatens to increase animal suffering and decrease species integrity, while at the same time creating a potentially devastating impact on the balance and sustainability of the Earth's ecosystem. Regardless, the value judgments we make regarding the direction and scope that this technology should take are sure to have far reaching implications.

I. A Review of the Technology

Transgenic animals are animals that have, through genetic engineering, genes from other plants and animals. Unlike controlled breeding, which is confined to the genetic material contained in a single species, modern genetic engineering permits an almost limitless scope of modification and introduction of otherwise foreign genetic material. This permits specific traits, and not the host of other traits common from crossbreeding, to be effectively introduced into new, transgenic animal species. Genetic engineering is able to create whole organisms that are not natural to the planet, and whose specific genetic make-up is as much a result of human manipulation as it is natural selection. (For further information on the basics of genetic engineering, see Detailed Discussion ).

II. Pros of Genetic Engineering

With regard to the agricultural industry, transgenic farm animals can be created, that are better able to resist disease, grow faster, and more efficiently reproduce than current species of animals. Transgenic sheep can be created to produce better wool and cows can be engineered to more efficiently convert grain into higher quality milk and meat. Transgenic salmon, salmon that grow larger and at a faster rate than natural varieties, have already been created and farmed. (For further information on the potential benefits, see Detailed Discussion ).

One of the more controversial uses of this technology is found in recent proposals to engineer farm animals to be non-sentient, without the "stress" genes that cause them great suffering during their lives on industrial factory farms. Since sentience, the ability to feel pain and experience suffering, is the basis upon which much animal rights ideology is based, some argue that these types of transgenic farm animals would help to solve many of the animal welfare issues posed by industrial factory farms. (For more information on the risks, see Detailed Discussion ).

The bio-medical research industry has been equally influenced by genetic engineering technology. Instead of relying on numerous test animals to research modern diseases and appropriate drug therapies, the bio-medical community can now rely on specifically engineered animal research models. Such animals are bred to have an increase susceptibility to modern diseases, like hereditary breast cancer. Transgenic animals have made research of such diseases more accurate, less expensive and faster, while at the same time permitting accurate results with the use of fewer individual animals in any given study.

Also, transgenic animals, like goats, sheep, and cattle, have been engineered to produce large amounts of complex human proteins in their milk, something very useful in the creation of therapeutic drugs. By engineering these animals to release these and other proteins in their milk, the mass production of high quality therapeutic drugs is made less costly, easier to manufacture, and at the expense of fewer animal lives than what was formerly the case. (For more information on the scientific and medical potential of genetic engineering, see Detailed Discussion ).

Biotechnology breakthroughs in whole animal cloning have led to many suggestions that such technology could be used to clone endangered species. Cloning provides a great support blanket for the modern extinction crisis and can help to ensure that critical numbers of endangered species will exist for generations to come.

III. Cons of Genetic Engineering

In general, opponents of genetic engineering assert that such technology creates a huge diminution in the standing of animals, leaving them as nothing more than "test tubes with tails," only of benefit for the exploitive practices of factory farming, and drug and organ manufacturing. Creating more efficient agricultural animals threatens weaken the genetic diversity of the herd and thereby make them more susceptible to new strains of infectious disease. Also, if transgenic farm animals ever escape into wild populations, they can have profoundly disturbing effects on the natural environment, including a complete elimination of natural populations and the processes of natural selection.

Animal rights advocates also argue that each species should enjoy an inherent, natural right to be free of genetic manipulation in any form. This is especially the case when genetic engineering is used as a means of depriving animals of their sentience, of exacerbating the cruel, horrific conditions of the modern factory farm and biomedical lab. Although the sheer numbers may decline, the actual suffering experienced by agricultural and research animals may increase.

Cloning endangered species, although useful as a last resort, may unwisely shift our efforts away from protecting the critical habitat necessary to sustain viable endangered species populations. Habitat protection is as important to saving endangered species as is the specific renewal and maintenance of viable numbers within a population. Since limited funds exist, habitat protection, and not expensive cloning technology, should be the focus of our endangered species protection efforts. (For more information on the inherent dangers, see Detailed Discussion ).

IV. The Legal Terrain

Currently, there are few laws, in either the United States or the European Union (EU) regulating animal cloning and the creation of transgenic animals. In the United States, most research and farm animals are excluded from federal protection. While the European Union (EU) ensures that such animals are treated more humanely than is the case in the United States, both the U.S. and the EU extend patent protection to the owners and creators of transgenic animal species. This provides a huge incentive for the biotechnology industry to continually research and develop novel transgenic animal creations. With patents, researchers can now own and monopolize entire animal species, something unheard of prior to modern genetic engineering. The Supreme Court has upheld transgenic animal patents without any review of the potential ethical and environmental risks associated with the technology involved. (For more on this important decision, click here ).

Most modern legislation regarding genetic engineering and cloning technology ensued following the birth of Dolly the sheep, the first multi-cellular organism cloned from adult cells. The primary objectives of the subsequent United States and EU legislation was to ban human cloning while at the same time ensuring that genetic engineering research continued unimpeded by such legislation. Patent protection effectively promotes genetic engineering research and helps to ensure its speedy development. (For more information on U.S. and European laws concerning biotechnology, see Detailed Discussion ).

V. Conclusion

There is no doubt that genetic engineering of animals will continue well into the future. Both the United States' and the EU's legal systems have been slow to respond with legislation specifically regulating biotechnology, and each have permitted their patent law to provide a supportive ground for genetic engineering research and development. One thing is for sure, we must not sit complacently by as this technology rapidly changes the fabric of our existence from the inside out. We must not wait and see what the effects are. We must form educated opinions, inspire legislative regulation, and hope that whatever direction that bioengineering takes us, is a positive step towards decreased animal suffering, increased environmental sustainability, and an overall compassionate regard for the earth and its precious life.


The male reproductive system produces the germ-cells further, other part of the reproductive system delivers the produced germ-cells to the site of fertilization.

The formation of sperms or germ-cells takes place in the testes.

The formation of sperm typically requires a lower temperature than the normal body temperature.

The testes secrete hormone, namely testosterone that brings changes in the appearance of boys at the time of their puberty.

The formed sperms are then delivered through the vas deferens, which unites with a tube coming from the urinary bladder.

The urethra, likewise, acts as a common passage for both the sperms and urine.

The sperms are fluids that consist of mainly genetic material it has a long tail that helps to move towards the female germ-cell.


Reproductive Biology

Reproductive Biology is an international, quarterly, peer-reviewed journal publishing high quality original research articles, short communication, technical notes, reviews and mini-reviews dealing with all aspects of reproduction.

Reproductive Biology covers a broad scope of reproductive biology and.

Reproductive Biology is an international, quarterly, peer-reviewed journal publishing high quality original research articles, short communication, technical notes, reviews and mini-reviews dealing with all aspects of reproduction.

Reproductive Biology covers a broad scope of reproductive biology and reproductive medicine translational research articles, providing a platform for scientific exchange of knowledge. The journal publishes state-of-the-art articles on reproductive physiology, endocrinology with a special attention to endocrine related cancers, receptor studies, andrology, embryology, infertility, assisted reproduction, contraception, obstetrics and gynecology, as well as animal breeding and animal reproduction (with a special emphasis to farm animals).
Papers from both basic and clinical research areas will be considered.


Growing and Reproducing

All living things are able to both grow and reproduce themselves. In some cases growth may not be readily apparent, but each living organism will increase in cellular size, volume or number throughout its lifespan. Living things also reproduce themselves and pass their genetic information on to offspring. This can occur either sexually, by combining the genes of two genetically distinct parents, or asexually, by creating a genetic copy of a single organism.


Many species of annelids (worms) reproduce via an asexual process called fragmentation. Included in this category of worms are California blackworms, or mudworms. These worms are hermaphroditic -- they have both male and female reproductive parts -- and can reproduce sexually. However, many times these worms will reproduce using fragmentation. In this case, blackworms can break apart and each consequential fragment can become a new worm.

Hydras are a type of freshwater cnidarian related to jellyfish, sea anemones and corals. Hydras reproduce asexually by developing small, genetically identical polyps that protrude from the parent. These polyps break off from the parent to form a new organism in a process called "budding."


Want to Get Along With Robots? Pretend They’re Animals

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Photograph: Kiyoshi Ota/Bloomberg/Getty Images

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Pigs, rats, and locusts have it easy these days—they can bother whoever they want. But back in the Middle Ages, such behavior could have landed them in court. If a pig bit a child, town officials would hold a trial like they would for a person, even providing the offender with a lawyer. Getting insects to show up in court en masse was a bit more difficult, but the authorities tried anyway: They’d send someone out to yell the summons into the countryside.

That’s hilarious, yes, but also a hint at how humans might navigate a new, even more complicated relationship. Just as we can’t help but ascribe agency to animals, we also project intent, emotions, and expectations onto robots. “It has always struck me that we're constantly comparing robots to humans, and artificial intelligence to human intelligence, and I've just never found that to be the best analogy,” says MIT robotics ethicist Kate Darling, author of the upcoming book The New Breed: What Our History with Animals Reveals about Our Future With Robots. “I've always found that animals are such a great analogy to get people away from this human comparison. We understand that animals are also these autonomous beings that can sense, think, make decisions, learn. You see a more diverse range of skill and intelligence in the animal world.”

Is the backflipping humanoid robot Atlas rather humanlike? For sure. But Spot the robot dog certainly is not. Neither are robots that roll, slither, or swim. Humans are already forming complex bonds with robot pets and even with Roombas. Robots of all kinds are on track to replicate the many ways that animals have been integrated into human society—as brute labor, as coworkers, and as companions. They’re very much a new breed, and we’ll need to navigate new kinds of relationships with them. WIRED spoke with Darling about how we might do that without having our descendants laugh at us like we laugh at the animal trials of the Middle Ages. (The conversation has been condensed and edited for clarity.)

WIRED: The metaphor of robots and animals is particularly powerful because it spans such a range of roles that we want robots to assume. We put oxen to work doing a very specific job that frees up humans to do the not-horrific part of farming. But you also see this in companion robots filling the role of an actual pet, a cat or a dog.

Kate Darling: We've used animals in war, we've used them as our companions. We've domesticated them, not because they do what we do, but because they have skill sets that are supplemental to ours. So when we're thinking about robots, instead of trying to think about recreating ourselves, we should be thinking more about: What are the skill sets that can complement our own? Whether that's out in the agricultural fields, or whether that's in the companionship area—which also tends to be a conversation full of this moral panic about robots replacing human relationships. Really, with animals, we've seen that we were able to incorporate them into our world of diverse relationships, because what they offer is different from what people offer.

WIRED: All you have to do is visit one robotics lab anywhere in the world to realize that the machines are nowhere near our capabilities as humans. But why is this narrative so persistent?

KD: One of the things that always fascinated me about robots is that we do project ourselves onto them. We do constantly compare them to ourselves. And it does lend itself to these narratives about dystopian robot takeovers, because we just assume that the robots might want to do the same thing that we as humans might do. Although I have to say, a lot of the dystopian robot takeover narratives are more in Western culture and society. There are other cultures where robots are seen more as partners, and less as this scary thing that could take over. We have a long history of science-fiction pop culture that plays with these future ideas of what robots will be capable of, and it's very divorced from the reality of where technology development is currently.

WIRED: One of the things I always find so captivating about robotics is that engineers can invent a form factor that has never evolved in an animal. So obviously, Spot is a quadruped, Atlas is a biped—those are tried and true methods of locomotion in the animal kingdom. But evolution never invented the wheel for an organism, because that would be impossible.

KD: One of the points that I try to make in the book is that using the animal analogy is not because I think robots and animals are the same, or all robots should be designed to be like animals. Obviously, it's super useful to draw from biology, whether that's quadruped or biped. We know that biologically inspired design has a lot of usefulness, because animals and humans have evolved over so many years to have very useful abilities.

The WIRED Guide to Robots

However, the book's called The New Breed because what I really want is for people to just open their minds to what other possibilities are out there. I feel like way too many robots are designed to look like humanoids that have two arms, two legs, a torso, a head. And there's always this argument that we need to design robots that look like us because we have a world that's built for humans, with staircases and doorknobs. But bipedal robots are super expensive and complicated to engineer. And like you said, wheels are maybe much more useful.

Then there's also the argument that robots need to look like us for us to relate to them emotionally. We know from over 100 years of animation expertise that that's not true. You have to put some sort of social cue or human emotion into the design, but it doesn't have to look like a human for us to relate to it.

WIRED: That brings us nicely to the idea of agency. One of my favorite moments in human history was when animals were put on trial—like regularly.

KD: Wait. You liked this?

WIRED: I mean, it's horrifying. But I just think that it's a fascinating period in legal history. So why do we ascribe this agency to animals that have no such thing? And why might we do the same with robots?

KD: It's so bizarre and fascinating—and seems so ridiculous to us now—but for hundreds of years of human history in the Middle Ages, we put animals on trial for the crimes they committed. So whether that was a pig that chewed a child's ear off, or whether that was a plague of locusts or rats that destroyed crops, there were actual trials that progressed the same way that a trial for a human would progress, with defense attorneys and a jury and summoning the animals to court. Some were not found guilty, and some were sentenced to death. It’s this idea that animals should be held accountable, or be expected to abide by our morals or rules. Now we don't believe that that makes any sense, the same way that we wouldn't hold a small child accountable for everything.

In a lot of the early legal conversation around responsibility in robotics, it seems that we're doing something a little bit similar. And, this is a little tongue in cheek—but also not really—because the solutions that people are proposing for robots causing harm are getting a little bit too close to assigning too much agency to the robots. There's this idea that, “Oh, because nobody could anticipate this harm, how are we going to hold people accountable? We have to hold the robot itself accountable.” Whether that's by creating some sort of legal entity, like a corporation, where the robot has its own rights and responsibilities, or whether that's by programming the robot to obey our rules and morals—which we kind of know from the field of machine ethics is not really possible or feasible, at least not any anytime soon.

WIRED: I wanted to talk about navigating relationships with home or companion robots, especially when it comes to empathy and actually developing pretty complex relationships. What can we learn from what we've been doing for thousands of years with pets?

KD: One of the things that we've learned by looking at the history of pets and other emotional relationships we've developed with animals is that there isn't anything inherently wrong with it—which is something that people often leap to immediately with robots. They're immediately like, “It's wrong. It's fake. It's going to take away from human relationships.” So I think that comparing robots to animals is an immediate conversation-shifter, where people are like, “If it's more like a pet rabbit, then maybe it's not going to take away my child's friends.”

One of the other things we've learned is that animals, even in the companionship realm, are actually really useful in health and education. There are therapy methods that have really been able to improve people's lives through emotional connections to animals. And it shows that there actually may be some potential for robots to help in a similar, yet different, way—again, as kind of a new breed. It's a new tool, it's something new that we might be able to harness and use to our benefit.

One of the things that was important to me though to put in the book is that robots and animals are not the same. Unlike animals, robots can tell others your secrets. And robots are created by corporations. There's a lot of issues that I think we tend to not see—or forget about—because we're so focused on this human replacement aspect. There are a lot of issues with putting this technology into the capitalist society we live in, and just letting companies have free reign over how they use these emotional connections.

WIRED: Say you have a home robot for a kid. In order to unlock some sort of feature, you have to pay extra money. But the kid has already developed a relationship with that robot, which you could argue is exploiting emotions, exploiting that bond that a child has developed with a robot, in order to get you to pay more.

KD: It's kind of like the whole in-app purchases scandal that happened a while back, but it'll be that on steroids. Because now you have this emotional connection, where it's not just the kid wanting to play a game on the iPad, but the kid actually has a relationship with the robot.

For kids, I'm actually less worried because we have so many watchdog organizations that are out there looking for new technologies that are trying to exploit children. And there are laws that actually protect kids in a lot of countries. But the interesting thing to me is that it's not just kids—you can exploit anyone this way. We know that adults are susceptible to revealing more personal information to a robot than they would willingly enter into a database. Or if your sex robot has compelling enough purchases, that might be a way to really exploit consumers’ willingness to pay. And so I think there needs to be broad consumer protection. For reasons of privacy, for reasons of emotional manipulation, I think it's extremely plausible that people might shell out money to keep a robot “alive,” for example, and that companies might try to exploit that.

WIRED: So what does the relationship between robots and humans look like in the near future?

KD: Roomba is one of the very simple examples where you have a robot that's not very complex, but it's in people's homes, it's moving around on its own. And people have named their Roombas. There's so many other cases, like military robots. Soldiers were working with these bomb disposal units and started treating them like pets. They would give them names, they would give them Medals of Honor, they would have funerals with gun salutes, and really relating to them in ways similar to how animals have been an emotional support for soldiers in intense situations throughout history.