PART ONE OF AMAZING SPECIES: INDESTRUCTIBLE ORGANISMS

Hey everybody so its been a while since my last post, but I'm back now. There are millions of species on planet earth, some big,

African Elephant and Blue Whale

some small

Ladybug and Humming Bird

some fast, and some slow.

Galapagos Tortoise, Cheetah, Peregrine Falcon

For today however, lets focus on some lesser known species. These organisms may not be as flashy as others but to paraphrase a certain famous Osteichthyes, they just keep swimming (or crawling or whatever).


These are the creatures who will still be doing their thing long after all of us "higher" lifeforms have kicked the bucket. (and no I'm not talking about the cockroach)

Lungfish

Queensland Lungfish (Neoceratodus forsteri)

There are several extant orders of lungfish scattered across most of the world. Lepidosireniformes in particular are split between the families, Lepidosirenidae (South American lungfish) and Protopteridae (African lungfish). These fish are capable of some incredible feats of endurance. As they are primarily found in shallow, anoxic swamps which can experience periods of drought these fish have evolved to breathe air. Their air bladder has become essentially a "lung" and their heart is even capable of circulating oxygenated and deoxygenated blood separately to separate parts of their bodies. The South African lungfish has taken this resistance to drought to the extreme, and has been recorded as surviving 4 YEARS out of water! It achieves this miraculous feat by burrowing itself into the mud at the bottom of its swamp and wrapping itself in a cocoon of mud. It then enters a hibernation like state of suspended animation during which its metabolism is reduced to almost 1/60th of its normal rate to reduce waste production.

Clip of Lungfish from BBC Documentary

Bdelloidea

Bdelloidea

Bdelloidea is a class of microscopic, asexual organisms which inhabit a range of freshwater habitats around the world. There are more that 450 classified species of Bdelloidea which comprise a genetic lineage approximately 25 million years old. These organisms have survived that long in large part due to their remarkable durability. They, like the lungfish, are capable of surviving prolonged desiccation; in their case Bdelloideas have been shown to "resurrect" following 9 years without water. They do this by preemptively dehydrating themselves in a process known as anhydrobiosis. Bdelloideas remain in a dormant state until the surrounding conditions are favorable enough to awaken them. Not only does this state allow them to endure long droughts, the stress of desiccation and re-hydration actually improves their fitness and fecundity.

As asexual organisms, Bdelloidea are susceptible to a major evolutionary hurdle not experienced by sexually reproducing creatures. According to a hypothesis of co-evolution known as the Red Queen Hypothesis, asexual species are especially vulnerable to rapidly evolving parasites and pathogens. This is due to asexual species being unable to quickly alter their genotypes to combat rapid parasite evolution. However, Bdelloidea have several characteristics which circumvent this. Firstly they can survive desiccation which would kill most parasites and pathogens. Secondly, while in their dehydrated form they are easily carried away by winds, and can form new colonies elsewhere if favorable conditions are present. Finally Bdelloidea have been shown to utilize horizontal gene transfer upon re-hydration. This has allowed them to steal genetic material from bacteria, fungi, and plants nearby (~10% of their genome is comprised of this stolen DNA). There is no consensus at this point as to how or why Bdelloidea perform this gene theft.

Bdelloidea rotifers

One final benefit of the Bdelloideas incredible anhydrobiotic state is the remarkable defense it provides from harmful radiation. Studies performed on two species of Bdelloideas (Adineta vaga and Philodina roseola) have shown they posses an extraordinary resistance to ionizing radiation and the ability to efficiently repair double stranded DNA breaks. Researchers have suggested that these abilities are likely a result of the desiccation resistance adaptations.

Hydra

Hydra

Remember those stories you heard as a kid about how if you cut a worm in half it would grow into two worms? Pretty cool right? Unfortunately for worms it isn't true so we should probably stop telling people that. There are creatures with tremendous regenerative powers. Some sea stars can regrow their entire bodies as long as at least 1/5th of their head remains intact, and sponges/sea cucumbers/flat worms can in fact reproduce by being divided into small sections. However, the Hydra surpasses them all. This genus of tiny, freshwater creatures possess regenerative capabilities rivaling its namesake.

The Hydra fight from Disney's Hercules

While the Hydra of legend would grow two heads to replace each that was lost, the real Hydra goes even further in its ability to survive dismemberment. These organisms have the ability to completely reconstitute their bodies after being chopped, diced, sliced, and smashed into a pile of goo. The key to their incredible regeneration is their specialized "command cells". Rather than a traditional brain Hydra use these "command cells" to instruct other cells in their bodies. Following being turned into a puddle all they need to reform is for 5-20 of these "command cells" to remain intact in order for them to instruct the destroyed cells to reform into the Hydra. Technau et al. (2000) showed that this small group of cells would signal the surrounding cells to reform into a new Hydra in less than 96 hours. While that may seem like a long time remember its still faster than you could reform after being turned into hamburger.

Sound familiar? Yes. Hydras are elves.

This regenerative power of the Hydra gives rise to an additional remarkable ability. They do not age. That's right, Hydra are biologically immortal. Their stem cells have can renew themselves indefinitely. This is incredible because it means that unless some outside force kills them they will live forever.

Tardigrade

Tardigrade aka: Water Bear

While you may think you've seen some incredible, indestructible creatures so far, to quote Bachman-Turner Overdrive "You ain't seen nothing yet!". Here we come at last to the end, and what do we find here? The Tardigrades otherwise known as Water Bears. Tardigrades are an entire phylum of microscopic, eight legged, water dwelling, segmented creatures which are found in virtually every environment and habitat on the planet. From the bottom of the oceans to the tops of mountain ranges and the frozen wastelands of Antarctica to the sweltering jungles of the Amazon there is nowhere on Earth you can not escape the Tardigrades.
So far on this list we've covered organisms which can survive extraordinary periods of dehydration and being smashed into tiny pieces. We've met fish which bury themselves in mud for a decade and creatures which do not age. However, the Tardigrades put them all to shame.

Tardigrades can/are:

Perform cryptobiosis, essentially stopping their metabolism dead. Tardigrades can reduce their metabolism to below 0.01% of its normal function. Not only are they capable of basically stopping their bodies from functioning, but they can do it in multiple ways. They can undergo anhydrobiosis (caused by lack of water, like the Bdelloidea), cryobiosis (in response to reduced temperatures), osmobiosis (when their water becomes hyper-saturated with solute), or anoxybiosis (when there is a lack of oxygen). Tardigrades can survive in this state, referred to as a tun, for more than 5 years. They have also been reported to undergo chemobiosis (a response to high levels of toxins in the environment) but this has not been confirmed.

Survive a greater range of temperatures than any other creature on earth; from -272 C (almost absolute zero, ~1 K) to 151 C (-458 F - 304 F).

Withstand the vacuum of space as well as the crushing depths of the ocean floor. Some species can survive ~6000 atmospheres of pressure, which is almost six times greater than the pressure found at the bottom of the Marianas Trench.

Dehydrate from ~85% water to ~3% water body composition. They can survive in this dehydrated state for at least a decade, although there are reports of limb movement (not generally considered survival) after 120 years!

Incredibly resilient to radiation. They can survive doses of ionizing radiation nearly 1000 times the lethal dose for most other organisms. This has been attributed to their ability to dehydrate which reduces the reactants for the radiation. However, they have also been found to be remarkably resilient while hydrated, due in large part to their incredibly efficient ability to repair their DNA.

Live in the vacuum of space, unaided for up to 10 days. They are the only organism we know of that can survive the pressure, lack of oxygen, and immense radiation of space for a significant length of time.

Tardigrades, courtesy of Cosmos: A Space Odyssey

It seems that the only way to kill these unstoppable creatures is through mechanical pressure (squish them). That however becomes a little difficult as they are microscopic, and live in water. Have you ever tried stomping on something in a puddle? Unless its sitting on the bottom too dense/heavy for the water to lift its really freaking hard.

So how did Tardigrades become the unkillable monsters of the micro-world? Researchers believe that it is their ability to perform horizontal gene transfer (HGT). As we mentioned earlier with the rotifers, this is the ability to steal genes from other organisms in this case mainly bacteria. This most likely happens as a result of the Tardigrades dehydrating and re-hydrating themselves. When they dehydrate they break down their DNA, then upon re-hydration they are susceptible to sucking up foreign matter and DNA. Combine these facts with their previously stated remarkable capacity for DNA repair, and viola freaky new Frankenstein's Monster DNA. One species of Tardigrade had its genome sequenced by researchers from the University of North Carolina. They found that a full 6th of its genetic material (17.5%) was taken from other organisms mainly bacteria (Archea). They also found that the Tardigrades use this "stolen" DNA during times of stress which indicates that at least part of their legendary durability is due to their ability to absorb genetic material from others. Basically the more resilient you are to drying out, the more material you can absorb which in turn makes you more resilient to drying out, and so on etc. The researchers concluded by saying that the species they investigated, Hypsibius dujardini, is actually kind of a wuss compared with other species, and that the genomes of its hardier relatives may show even greater percentages of foreign DNA.

Cosmos: A Space Odyssey

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Black and White

Holy Shit! Have you guys seen this?

Albino Green Sea Turtle (Chelonia mydas)

GHOSTS ARE REAL! I'm kidding obviously, but seriously how adorable is that? Just when you thought baby turtles couldn't be cuter. But what's the story behind this crazy white turtle? Well first off it's not alone.

Various albino animals.

All of these animals are affected by a congenital condition known as albinism characterized by a reduction or lack of pigment in the skin, hair, scales, etc. as well as pink/blue eyes. Albinism is also found in humans and less commonly in plants where the chlorophyll in the plants is reduced. This negatively affects the plant's ability to photosynthesize which leads to reduced survivability. Albino animals also suffer from their reduced pigment as it can negatively affect their ability to camouflage, or reduce their protection from UV radiation. There have also been studies showing that albino animals have poor eyesight and hearing as well as reduced reproductive viability.

Now while albino animals are strange and eye-catching there is another pigment affecting condition that often gets overlooked. Did you know that these two animals are actually the same species?

Black "Panther" and Jaguar (Panthera onca)

The black panther, as it is commonly called, is actually a title used to describe any of the Panthera species affected by a condition known as melanism.

Top Row: Melanistic and normal jaguar (Panthera onca); Bottom Row: Normal and melanistic leopard (Panthera pardus)

Melanism is the opposite of albinism. While the latter is a condition resulting in the absence of pigment in the skin, hair, etc. the former is a condition which increases the amount of pigment produced. Additionally while albinism has several negative impacts, as described above, melanism is more commonly a beneficial condition. The darker pigmentation can grant greater camouflage capabilities to both predators and prey is many environments, especially at night. Melanism has also been linked to disease resistance in felines; with darker individuals appearing at higher latitudes and in environments where they would be disadvantaged camouflage-wise due to their ability to shake off viruses better than their "normal" coated cousins. Finally there is a wide range of species affected by melanism, from snakes, cats, squirrels, canines, and insects.

Various melanistic animals.

The incidences of this condition in insects are most famously linked to increased pollution from industrial development. For example the peppered moth, Biston betularia, was originally white which camouflaged it against the light colored lichen on the trees. However, with the rise of air pollution in the UK following the industrial revolution the lichen began to die off exposing the dark bark of the trees. This lead to a rise in melanism in the moths as the lighter colored individuals became more obvious to predators.

Peppered moth (Biston betularia) normal and melanistic varieties

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A craftsman is only as good as his tools

Clip from Hitchhiker's Guide to the Galaxy tv series.

Words of wisdom from the late, great Douglas Adams. One of the identifiers, and markers of intelligence in a species is the use of tools. For a long time humanity assumed that it was the sole species to possess this trait. However, the creation and use of tools is a trait that has been documented in numerous species throughout the years. Here we shall discuss as many of them as I feel like typing about.

1. Primates

Ok this one is a bit of a cheat because so many of our closest genetic relatives have displayed a talent for tool creation and usage. So I'm going to briefly touch on several species of primates in no particular order.

First off is the most obvious, Chimpanzees (Pan troglodytes). Chimps are one of our closest genetic relatives, along with Bonobos (Pan paniscus), sharing approximately 98.7% of our genetic code.

From Left: Chimpanzees, Human, Bonobos. Johnny Depp is 98.7% genetically identical to the animals on either side of him.

Chimps and bonobos have been documented crafting and using tools in the wild, but both species have a much higher tool usage rate when held in captivity. Tool usage in these species is widely varied with tools being developed to hunt, scavenge, collect honey and water, crush and chop fruits, nuts and vegetables, and for personal grooming.

Chimps using tools to fish out insects.

Another great ape species which utilizes branches and leaves as a remarkable variety of tools for a multitude of jobs is the Orangutan (Pongo pygmaeus and Pongo abelii). Orangutans have been observed to use tools for many functions similar to chimps and bonobos. They craft hunting and gathering tools, use leaves as gloves to grab thorny branches, and use leaves as napkins. They have even been shown to utilize leaves as megaphones, possibly to make themselves seem larger and more threatening to predators. However, they have also shown a trait that you might think is a uniquely human idea. They have been observed using tools to masturbate. Yeah you read that right. Orangutans fashion tools to help them "get off", and it's been seen in both male and female orangs. While this is certainly the most eye grabbing trait, orangs have also shown a remarkable ability to "ape" (hehehe) human tool use. In the wild orangutans have been observed copying humans spear fishing, and in captivity they have been taught to craft stone hand axes.

Orangutan attempting to spear fish.

Finally among the non-ape primate species the most notable are the capuchin monkeys. Capuchins are part of the new-world monkey subfamily Cebinae, and are split into two genuses, Cebus and Sapajus. Capuchins of both genus have shown a remarkable propensity towards stone tool use. They have been documented using a stone "hammer and anvil" to crush and crack open nuts, fruits and even oysters. However, this is not some innate ability of these monkeys. It can take up to 8 years for Capuchins to master the skills required to use these tools.

Clip from BBC Earth documentary showing Capuchin monkeys cracking

nuts. Narrated by the brilliant Sir David Attenborough.

Capuchins have also shown ingenuity by using stone tools to dig up roots and tubers, and "milking" the secretions of certain arthropods to use as insecticides.

2. Elephants

There are three extant species of elephant, the Asian elephant (Elephas maximus), African bush elephant (Loxodonta africana), and African forest elephants (Loxodonta cyclotis). While these species are famed for their "infallible" memories and are considered among the most intelligent species on the planet, they are not often thought of as tool users. They make up for their lack of opposable digits through the use of their incredibly dexterous trunks. Elephants have been seen choosing, stripping and shaping sticks and branches for a variety of purposes. They create fly swatters, back scratchers, and toe cleaners. They have also shown foresight in their tool creation. Elephants have been observed digging holes which fill with water, then filling the hole with a wad of chewed bark to absorb the water, and covering the hole over with sand to prevent evaporation. This creates a cache of water for the elephant should it return later and need a drink. Elephants have also shown the ingenuity to use large rocks to crush electric fences, either shorting them out or breaking a hole for the elephant to walk through. In captivity Asian elephants will also use boxes in their enclosure as stepping stones to reach food placed purposefully out of reach.

Elephant chews stick to create tool for scratching.

3. Sea Otters!

I had to include this one. As you may have noticed from the background and the title of my blog I have a weak spot for otters. Now tool use is fairly uncommon in the animal kingdom, while it may not appear so from this blog so far, but it is even more unusual in the marine environment. Sea otters (Enhydra lutris) however, are one of the few species with documented tool use capabilities.

Sea Otter using rock on its belly to smash its prey.

I'm sure we're all familiar with the images and videos of sea otters holding the clam, or urchin on their belly and smashing it with a rock to open it. It turns out that sea otters also use rocks to remove their food from the sea bed and rocks it clings to. Otters hunting abalone (a type of marine snail) will often use rocks to bash the snail in an attempt to prize it from the rocks it is attached too. This is much harder than it sounds as the snails can grip the rock with a force equal to 4,000x its own body weight!

Once the otter has prized the snail from the rock (usually requiring several dives to achieve this) it must then break through the snail's hard shell. Recently a researcher from Monterey Bay Aquarium, Jessica Fujii, reported that her team had found that the rate of tool use in otters varies by location. Sea otters down south, off the California coast showed a much higher rate of tool use than those observed in Alaskan waters. Fujii said that this is due to the dominant prey species for these different populations of otters. While urchins are spiny and tough looking, they are actually much easier to break open than the abalone that otters hunt further south. This explains why Alaskan otters showed tool use while eating ~1% of the time compared with the ~16% usage rate by southern otters.

Sea otter using rock to smash open clams.

4. Dolphins

Finally we have come full circle. Here we find the species many consider to be the second most intelligent on the planet, the bottlenose dolphin (Tursiops truncatus). Dolphins are similar to elephants in that while the intelligence is much lauded, they are not considered prime examples of tool using species. However, dolphins have been observed using sponges to protect their rostrum as they hunt for fish along the sea floor. Genetic studies performed on dolphins in Shark Bay, Australia (where this behaviour has been documented) show that it stems from a single matriline (female lineage) with mother's apparently teaching the skill to their daughters. There are also reports of dolphins in this area using conch shells to scoop prey off the bottom making them easier for the dolphins to eat. Dolphins have, like Orangutans, also been documented masturbating in the wild. While perhaps not technically "tool use" a video does exist showing a river dolphin "using" a headless fish.

Bottlenose dolphins in Shark Bay using sponges to protect them while hunting.

Well that's all I have for this blog, thanks for checking it out. I hope you enjoyed the pictures and videos. Come back again soon, and check me out on The Imposter Podcast, run by a good friend of mine, Amir Fogel. Anyway thanks for stopping by!

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