Alien Biospheres: Part 5 – Terrestrial Diversity and Ecology

Alien Biospheres: Part 5 – Terrestrial Diversity and Ecology


In the last episode, we saw how the chemophytes,
tentaclostomes, and sarcopods underwent the adaptations necessary to leave the water behind
and become the first organisms to live exclusively on dry land. But evolution isn’t a linear process, and
as these groups make the transition to land, they’ll continuously diversify to fill the
myriad niches offered by their new terrestrial habitat. To begin with, the environment our alien organisms
find themselves in, having emerged from the water will be warm, wet, and tropical. Our alien planet has a higher average temperature
than earth and less seasonal variation, plus the abundant hydrogen sulfide undergoes a
series of reactions in the upper atmosphere to form sulfuric acid, around which will condense
voluminous clouds that bring acid rain. On top of that, the high temperatures and
single enormous ocean serve as a mechanism for generating gigantic storm systems called
hypercanes, larger than any storms seen on earth. All of these factors mean the mainland will
be perpetually drenched by massive bouts of acid rain, which will erode the mountains
into weather-beaten crags and valleys, and carve out huge river courses and deltas, and
much of the land will be taken up by water-logged marshes and bogs. This warm wet climate will be ideal for the
chemophytes, which will pave the way for the first terrestrial ecosystems. Just as in the oceans, the primary energy
sources for terrestrial organisms will be sunlight and atmospheric hydrogen sulfide,
both of which are used by the chemohphytes to power their autotrophic reactions. The first chemophytes will be small, slime
mold-like organisms, no more than a few centimeters tall at the most, but the clade from which
the terrestrial plants descend, which we’ll call Xenophytes, will evolve the specialized
tissues necessary to grow roots and stems to take up minerals from the soil and grow
upward to gather more sunlight. And one clade of these plants, which we’ll
call the Xylophytes, may then evolve tough support tissues to let them grow into the
first trees. Before the animals come ashore, there’ll
be nothing around to eat these plants, with one notable exception. Saprotrophs are organisms that absorb nutrients
from dead or decaying organic matter. The most recognizable saprotrophs on earth
are fungi, but saprotrophy also exists among bacteria and even some plant species as well. In these ancient forests, dead plant matter
represents an as-of-yet unexploited source of nutrients, so it’s very likely that a
clade of chemophyte will evolve a saprotrophic lifestyle. The chemophytes may be especially suited for
saprotrophy because organic decomposition gives off hydrogen sulfide, from which chemophytes
derive a portion of their energy. One clade of chemophyte may adapt their roots
to absorb more hydrogen sulfide and other nutrients from the bountiful leaf litter that
covers the forest floor. As they specialize for this mode of nutrition,
they may no longer rely on photosynthesis to obtain sugars, and so their leaves may
shrink, possibly even forsaking their algal symbionts and so losing their reddish coloration. These chemophytes, which I’ll call necrophytes,
will be the first terrestrial decomposers, organisms that breakdown the detritus that
litters the ground and recycle the nutrients, a role vital for all ecosystems. Things will remain this way until the tentaclostomes
launch their invasion of land, which is likely to occur alongside or very shortly after the
first terrestrial plants. The early amphibious forms may flourish around
the water’s edge, but the lophostomes will have the advantage in inland habitats. The first lophostomes will most likely be
adaptable generalists, since they won’t have had much time to specialize for living
in the forests. In this new environment, their survival rates
may be fairly low, so they’ll be incentivized to reproduce quickly and frequently to maintain
a stable population. This strategy of rapid reproduction is sometimes
called “r-selection”. R-selected species are those who produce large
numbers of offspring, of which only a small proportion survive. R-selected species tend to be small, have
short lifespans, and often thrive when colonizing new habitats. The sessile anthostomes also exhibit this
mode of reproduction with their broadcast spawning, and so the lophostomes may inherit
similar reproductive tendencies, producing thousands of eggs in a single spawning, the
majority of which will die before reaching maturity. As these lophostomes proliferate, they’ll
undergo a spurt of rapid diversification to fill all the various available niches, what’s
called an adaptive radiation. One clade of lophostomes may exploit the niches
of small-bodied creatures, shrinking down to only a few centimeters long. Below a certain size their shell won’t provide
any decent protection, so isn’t needed and may be lost entirely. A small size also means they won’t weigh
very much, and so will need comparatively little muscular effort to support themselves,
so their stubby legs may become longer and more flexible, which will also let them climb
plant stems and burrow through leaf-litter. Because they’re so low to the ground, even
the tiniest variation in terrain may obstruct their line of sight, so their eyestalks may
lengthen to into periscope-like structures to let them see over obstacles and increase
their field of view. These tiny lohpostomes will exploit similar
niches to those filled by arthropods on earth, and much like the arthropods, they may reach
staggering levels of diversity. Arthropods account for over 80% of all animal
species. The total species count of all chordates,
mollusks, flatworms, and round worms combined wouldn’t even be equal to the number of
beetle species alone. We’ll touch on this again later, but one
of the primary drivers of biodiversity is habitat variation, which is much more appreciable
on small scales, so our tiny lophostomes may reach levels of profusion comparable to the
arthropods. Also like arthropods, they may maintain the
r-selected tendencies of the earlier lophostomes, as r-selection tends to be favored at small
body sizes, since the only real way they can defend themselves against larger predators
is to reproduce faster than the rate at which their predators can eat them, much like the
tachypods that constitute the majority of marine plankton. I’ll call these tiny creatures malacoforms. Their diversity may be too great to adequately
catalogue, but we can still map out several major lineages. Early on in their evolution, some clades may
specialize for feeding on plants, forming the first link in the food chain. Some may evolve their manipulator limbs into
cutting tools to crop and process the softer tissues around the leaves and branches, while
others may evolve compact, robust mouthparts to bore through the harder tissues around
the stems and roots. While still others may evolve a proboscis
ringed with sharp serrations to pierce the plants’ outer cuticles and suck out the
nutrient-rich vascular fluids. As these herbivourous clades establish themselves,
other clades of malacoforms may evolve to feed on them. Some may adapt their tentacles into sharp
fang-like claws for impaling and butchering prey, while others may evolve longer, whip-like
tentacles to ensnare and restrain their prey. And some may evolve to become scavengers or
detritovores, feeding on carrion and decaying organic matter along with the necrophytes. Each of these groups may contain thousands
of species, and they’ll form the basis of just about every terrestrial ecosystem across
the planet. While the malacoforms may be incredibly diverse,
other lophostome clades may maintain a decent size as well as a hard shell. And as the oxygen levels increase with the
proliferation of the forests, they’ll be poised to attain comparatively large body
sizes, though they’ll still be limited by their lack of any skeletal support structure
and inefficient breathing mechanism. At their size, they won’t need long eyestalks
to see further, so they may shrink into compact, muscular turrets to reduce their likelihood
of being damaged, though they can still be swiveled forward and back to increase their
field of vision. And as these forms specialize for terrestrial
life, one clade may see a radical structural innovation in their digestive systems. We’ve said the entire gastrozoan branch
of the anthostome evolutionary tree has a blind-gut, meaning they eat and excrete waste
out of the same opening. This isn’t very efficient, since newly swallowed
food gets mixed in with food that’s already been digested. On earth, many clades have secondarily evolved
a through-gut from an ancestral blind-gut, so the same thing may happen in the lophostomes. Perhaps in one innovative clade, the gut evolves
a sort of partition to form into a U-shaped tract with separate canals for ingestion and
excretion. This development will help them extract more
nutrients from their food than other clades, and so these lophostomes, which I’ll call
diplostomes, may become the dominant group of large land animals of these ancient forests. A larger body size may result in these diplostomes
shifting from R-selection to K-selection. Instead of reproducing in vast numbers like
R-selected species, K-selected species produce fewer offspring, but invest more heavily in
those offspring to foster a higher chance of them surviving. K-selection tends to be favored by species
that are large, have relatively long lifespans, or live in crowded ecosystems or at high population
densities. The diplostomes’ increasing size may therefore
occur alongside a decrease in the number of fertilized eggs they produce in any given
clutch, from the several thousand eggs in the ancestral lophostomes to only a few hundred
or even several dozen in larger forms. However, to compensate, these eggs will be
larger and the larvae will be more developed when they hatch to give them a greater chance
of surviving to maturity. Keep in mind R and K selection exists on a
spectrum and most species will exist somewhere between the two extremes, and some species
might even alternate between them. For instance, the chemophytes reproduce asexually
to let them quickly colonize new or sparsely populated habitats, like an r-selected species,
but in areas that are already colonized or densely populated they switch to sexual reproduction
to maximize genetic variation, and they package their fertilized spores within a diaspore
to increase their chances of survival, like a k-selected species, which is actually very
similar to what many species of fungi do on earth. The diplostomes may become increasingly k-selected
as they evolve larger body sizes, which will be facilitated by the increase in atmospheric
oxygen as well as their efficient digestive systems. An immediate advantage provided by their complex
guts is an improved ability to cope with the tough indigestible tissues of large plants,
and so most early diplostomes may be herbivorous. One clade may specialize for herbivory by
evolving some of their feeding arms into long tentacles to reach for food, while the remaining
arms may broaden and become covered with row upon row of rasping teeth for masticating
vegetation before swallowing. The abundance of food in the ancient forests
may let this clade further increase in size to the upper limit of what their boneless
bodies will allow. As they grow larger, their legs may thicken
with rings of muscle to support a greater weight, possibly losing the ability to be
retracted within the body. But the evolution of large herbivores will
create a niche for predators that feed on them, so it will only be a matter of time
before one clade of diplostomes evolves carnivory. This transition may begin with a clade that
evolves to supplement their diet by subsisting on malacoforms or by scavenging carrion, gradually
becoming generalist omnivores. These creatures may be smaller than their
herbivorous cousins, and so won’t be quite as robustly built, and their generalist lifestyle
may require more mobility than dedicated herbivory, involving behaviors such as digging or climbing,
so their shells may become thinner and narrower so as to not hinder their movement. We’ll call these creatures Stenostracans,
which form a sister clade to the fully herbivorous diplostomes or Placostracans. One clade of stenostracans may fill the niches
of adaptable opportunists; while the placostracans continuously and indiscriminately gorge on
the bountiful vegetation, these creatures may be more selective in their feeding, so
some of their tentacles may evolve into antennae packed with scent organs to probe the leaflitter
for anything edible. Eventually, however, another clade of stenostracans
may complete the transition to carnivory by specializing to feed on larger prey, becoming
the first ever terrestrial macropredators. This transition may be facilitated by one
major development. Being apex predators, defense isn’t a priority
for this clade, while speed and maneuverability are critical to successful hunting, so this
new predatory clade may reduce their shells even further than other stenostracans. But rather than losing the shell completely
like the malacoforms, they may instead internalize it as a rigid structure within their body. Since the shell no longer provides any protection,
it may become diminished into a long flexible structure that provides internal support,
like the gladius of squids, or indeed like the backbones of vertebrates. This structure now serves as a site of muscle
attachment, giving them greater leverage and making walking much more efficient. They still won’t be able to run with any
great speed, but they’ll easily outpace the bulky herbivores they feed on. To pierce through their prey’s armor, their
tentacles may truncate and become lined with tooth-like barbs to deliver powerful bites. I’ll call these forms coleostracans. In response to these new predators, the other
diplostome clades will need to undergo defensive adaptations. The large placostracans may simply thicken
their shells and evolve extra armor, while the smaller omnivorous stenostracans will
still need to maintain a degree of flexibility, so they may divide their shells into bands
to provide protection without restricting their movement, possibly even evolving the
ability to curl into a defensive ball. I’ll call this clade the desmostracans. All of these various clades of lophostome
will enjoy millions of years of unrivaled dominion over the land before the sarcopods
come ashore to challenge their supremacy. Like the early lophostomes, the first osteopods
will likely tend towards r-selection to help them quickly colonize their new habitat, and
to that end, they might employ a unique reproductive capability. We said in part two that that the ancestral
polypod was dioecious, that is, having a distinction between male and female individuals, but what
if we add a slight variation to this? What if, like some species of fish, amphibians,
and arthropods on earth, the sarcopods, and the osteopods from which they descend, exhibit
sequential hermaphroditism, wherein they may alter their sex at some point during their
lifecycle. This contrasts with the lophostomes, whose
larvae don’t have any sexual characteristics at all, and its only once they reach maturity
that they become either male or female and remain as that sex for the rest of their lives. The osteopods’ sequential hermaphroditism
may provide an advantage because in any population where the proportion of males and females
is unbalanced, an individual can change sex to increase the likelihood of finding a mate
and helping the population remain stable. Unlike the early lophostomes, the first osteopods
will evolve among an already crowded ecosystem, so for the osteopods to adapt to any terrestrial
niches, they’ll need to compete with the dominant lophostome clades, but the osteopods
are provided with a considerable advantage from their internal skeletons and efficient
breathing systems, which will grant them much greater potential size and maneuverability
than the lophostomes. As the skeleton evolves, the osteopods may
split into two lineages. One may evolve multiple flexible limb girdles
for increased mobility and speed, while the other may evolve a single fused limb girdle
to support a larger body size. We’ll call these two lineages “polyschians”
and “synischians”, respectively. The early polyschians will be small and adaptable
omnivores, relying on their speed and agility to survive, while the synischians’ robust
skeletons will allow them to specialize for the niches of large ground-dwellers, rapidly
becoming the biggest land animals on the planet. As they get larger, their feet will broaden,
since if the feet are too narrow, they’ll sink into the ground, which would be especially
problematic in the muddy swamps that cover much of the landscape. Unlike tetrapods on earth, their feet won’t
bear any digits, instead consisting of a single toe-like claw with gripping surfaces on the
underside. Earth’s tetrapods inherited their fingers
and toes from their lobe-finned fish ancestors, but the sacropods from which the osteopods
descend have hydraulic feet instead of fins, and have no digits to speak of, so the osteopods
will likewise be toeless. The rise of these new clades will spark an
evolutionary battle between the lophostomes and osteopods for dominance of the terrestrial
ecosystems. The competitive exclusion principle states
that no two species can occupy the same niche within the same ecosystem without one outcompeting
the other. None of the lophostome clades can attain the
size that the synischians can, nor do they have the speed and maneuverability of the
polyschians, and so they may begin losing ground, but extinction isn’t the only possible
outcome. Niche partitioning is the process whereby
species competing for the same niche undergo adaptations for a more specific realization
of that niche such that they can coexist. For example, the various species of anoles
found on the Caribbean islands, while all filling the general niche of tree-dwelling
insectivores, avoid competition with each other by living in different microhabitats
defined by specific types of vegetation and levels of sunlight and moisture. The competing clades of lophostomes and osteopods
may do something similar, evolving to live in different habitats and competing for different
resources. For example, the desmostracans and polyschians,
both comprising adaptable omnivores, may avoid competition with each other by specializing
for different diets. The polyschians may take advantage of their
mobility to climb and live among tree branches, where they may feed on leaves and mixed plant
matter in addition to scavenging and hunting small prey. Their mandibles may broaden into chisel-like
structures to help cope with a variety of food items as well as to chew through the
tough outer cuticles of the trees in search of wood-boring malacoforms. To help them climb trees and clamber over
rough terrain, the gripping surfaces on their feet may evolve claws and their limbs may
lengthen to span the gaps between branches. Living in trees also serves as a defensive
adaptation, as they’ll be out of reach of the large ground predators, and many species
may complement this with camouflage patterns to let them blend into the red leaves of the
surrounding foliage. These will be some of the first arboreal animals,
living in a similar way to rodents or prosimians. I’ll call these creatures platydonts. The competition from these adaptable osteopods
may have an impact on the desmostracans, possibly resulting in many generalist species going
extinct and forcing the remaining species to adopt a more specialized lifestyle. They won’t be able to exploit tree-climbing
niches nearly as well as the platydonts, so may instead remain at ground level and specialize
to feed on the abundant malacoforms among the leaflitter, especially since the malacoforms
don’t require very much speed to prey upon. On earth, animals that occupy analogous niches
may be called insectivores, but of course, on this alien planet, there are no insects,
so for our purposes, I’m going to coin the term “malacovore” to describe their feeding
habits. To specialize for this lifestyle, some of
their tentacles may elongate into whip-like organs to snap up any malacoforms they unearth,
which will get crushed between the grinding surfaces of the two spade-like lower tentacles. Since this lifestyle demands less mobility
than that of their adaptable ancestors, they may become bulkier and more heavy-set, forsaking
a life clambering among the understory and now remaining exclusively at ground level. Similarly, the placostracans may avoid competition
with the herbivorous synischians by specializing to feed on different types of vegetation. The synischians may take advantage of their
size to exploit the niches of larger browsers, evolving long pedipalps to reach into high
branches. These pedipalps may terminate in hooked claws
to pull leaves toward the muscular mouth, and their cephalothorax may enlarge to accommodate
an expanded foregut to tackle tough woody vegetation. We’ll call these lumbering beasts megalobrachids. These adaptations, along with their great
size, will mean the megalobrachids will be able to feed on vegetation well out of the
placostracans’ reach, so the placostracans may respond by specializing for the niches
of heavy grazers, feeding on low vegetation on the forest floor, and as such, their feeding
tentacles, no longer used to reach into the trees for food, may become shorter and be
used for foraging among leaf-litter or digging for roots. Among predatory clades, niche partitioning
may drive the evolution of new hunting tactics. If a clade of polyschians evolves to become
predators, they may make use of their speed to specialize for pursuit hunting. Their hind legs may elongate and align to
be parallel with the body for a more directional application of force, allowing them to accelerate
explosively. Their eyes may move to the front of the cephalothorax
to provide them with increased depth perception, and their pedipalps may evolve sharp cutting
surfaces to butcher their kills. This collection of traits will give them the
speed and weaponry to chase down fast quarry like the platydonts, and to exploit similar
niches to those occupied by foxes and other canids on earth. I’ll call them Dromaeopods. The dromaeopods may outcompete many of the
predatory coleostracans, but those that survive may avoid the competition by specializing
for ambush tactics. Their gladius may evolve to become increasingly
lighter and more elastic, so that when the muscles within the back contact they bend
the gladius into a curve, storing energy like a bow, and when the muscles release, the gladius
snaps back into its original shape, propelling the animal forward in a sort of bounding lunge. This may lead to them evolving a bizarre inch-worm-like
mode of locomotion, as well as an impressive jumping ability, which they may make use of
to escape larger predators or to ambush prey. Many species may undergo further niche partitioning
by evolving to live among tree branches that are too high or precarious for the dromaeopods,
which are primarily adapted for life in the understory. Their walking legs may lose their weight-bearing
capabilities and evolve to grip and cling to the branches like forceps, as well as to
anchor themselves in place when lunging at prey. With these adaptations, these diplostomes,
which I’ll call elastospondyls, will become the most mobile lophostomes yet, perhaps sufficient
to become prolific arboreal ambush predators, feeding on the malacoforms and platydonts
they share the trees with. The megalobrachids, however may be too large
to be serve as suitable targets for either the elastospondyls or the dromaeopods, which
are specialized for hunting small, fast prey, but once again, where there’s a gap in the
food chain, something will inevitably evolve to fill it. In this case, early on in the synischian’s
history, the same stock from which the megalobrachids diverged may give rise to a clade of large
carnivores. They may use their strong pedipalps to grab
and restrain prey, while their eyes, much like those of the dromaeopods, may cluster
towards the front of the cephalothorax to help them zero-in on their target. Their mandibles may lengthen and become more
heavily muscled, while their teeth may extend and sharpen to slice through flesh. These creatures will become the new apex predators
of these early ecosystems and the largest carnivores of their time. However, despite their size and ferocity,
they may still retain some of the omnivorous tendencies of the ancestral synishcians, allowing
them to subsist on vegetation or carrion if need be, somewhat like bears or the extinct
entelodonts on earth. We’ll call these creatures deinognathans. And with that, our terrestrial ecosystems
are looking fairly well fleshed out, and our two body plans have seen some major developments
along the way. As always, keep in mind that these are only
the major groups we’re detailing here, and there are likely to be innumerable other clades
that come and go alongside them. This will serve as a rough outline for the
sort of ecosystems that may develop in the 50 million years or so following the appearance
of the first lophostomes. But there are omens of change on the horizon;
the climate is becoming cooler and dryer, and the tropical forests are thinning. The stable, hospitable habitats our species
have thrived in thus far won’t last forever, and so these clades will need to adapt to
a changing world, or face extinction. In the next episode, we’ll see how these
clades leave the ancient forests behind and undergo further diversification to conquer
a variety of new habitats across the supercontinent.

100 thoughts on “Alien Biospheres: Part 5 – Terrestrial Diversity and Ecology

  1. This is one of the best produced, most well thought out, polished series on any topic on YouTube. I've watched these since the Artifexian colab, and will eagerly await new parts.

  2. Please do a parasite version of Malacoformes, that neash is realy bogging my mind it is an easy way to evolve those

  3. How likly is for the next enviromental changes to drive the evolution of some eusocial species ?
    Also notice that the primordial supercontinent have some big islands arround it so maybe there the Diplostomas and the Oesteopodes didn't enter in contact with each other and evolved in isolation

  4. these creatures are just becoming more and more terrifying D: i can imagine that the red spider creature is the one to become intelligent though.

    you really put a lot of effort into these videos as they're truly amazing and incredibly fascinating. these videos are also very helpful as i have an interest in astrobiology. i'm very excited for the next episode!

  5. I love how you give the explanations for WHY the clades are evolving the way they are. Like the evolution of a tube-like gut leading to more efficient digestion and being able to utilize a new food source. It's those little details that I need to make my own ecosystems more realistic. (I'd love to see a high school biology class follow through this process, and what they'd come up with for their own planets ecosystem.)

  6. As allways a nice episode and i cant wait for the next one

    Also, my bet is that the elastic squid like thing will be one of the first species to evolve some sort of gliding mechanism as soon as the forest gets less dense

  7. imagine this as a game. itd be like spore on fucking steroids
    also waah waah spiders shut up we have australia

  8. 23:15 Jesus Christ this thing is 2m tall! Can you imagine how terrifying seeing this thing on earth would be!

  9. I don't know why you don't seem to want to reduce the number of body parts (legs, tentacles/mandible thingies, eyes,…) whereas it's usually a fairly common thing. There are many 4 or 6 legged species on Earth for instance, and those with more than that seem to be less common. The same goes for eyes or mouth parts. If there isn't a particular use for having so many of them, the energy cost of maintaining them all will be high and they will tend to shrink or fuse.

  10. Damn, who knew the sarcopods of all things would make such terrifying predators (especially the deinognathans)

  11. Wow I love this series. I also really like the elastic spines. I could see them evolving some webbing between their limbs that could help them glide.

  12. 13:32 FINALLY rolly-pollies FINALLY YASSS we can stop it right there, apex of the evolutionary tree of life

  13. We have a diversity problem here. This scenario can still work if life went very, very early out of water. But it's still weird that oceanic life would be so homogeneous. This isn't analogous to how life evolved and diversified on earth, and I don't see why there would be a difference.

    I hope the next video is about diversification in oceans.

  14. What program do you use to make your models? Blender? Do you make the textures yourself, or find them online? If so, where?

  15. I think you should put time spans like
    100 years after or put humun size comparation bcz its really hard to imagine them whithout thinkg they are avarege dog sized

  16. List of creatures and timestamps for them:

    3:04 – Necrophyta ("Death plants") – Sapotrophic Chemophytes

    6:09 – Malacoformes ("soft forms") – Small, mouse/insect-like Tentaclastomes with no shell

    6:25 – Ctenognatha ("comb jaws") – Herbivorous Malacoformes with comb-like tentacles and longer eye stalks

    6:32 – Barognatha ("heavy jaws") – Herbivorous Malacoformes with thicker jaws to grind plants

    6:39 – Aciculognatha ("needle jaws") – Herbivorous Malacoformes with a proboscis for drinking the Chemophytes' vascular fluid, AKA sap

    6:53 – Onychognatha ("claw jaws") – Carnivorous Malacoformes with really big teeth for eating other Malacoformes

    6:58 – Mastigognatha ("whip jaws") – Carnivorous Malacoformes with whip-like tentacles ending in teeth for eating other Malacoformes

    7:04 – Isognatha ("equal jaws") – Detritivorous Malacoformes that eat decaying matter

    8:39 – Diplostomes ("double mouths") – Tentaclastomes with very short eyestalks and a u-turn stomach, which gives them a makeshift anus directly below their mouth
    10:24 & 11:32 – Placostraca ("Plate shells") – Large, Herbivorous Diplostomes with two long tentacles to reach for leaves, the rest being shorter and broader to chew food better
    11:05 & 11:37 – Stenostraca/Eustenostraca ("Narrow shells")/("True Stenostracans") – Smaller, omnivorous, generalist Diplostomes with reduced shells
    13:05 – Coleostraca- ("Sheathed shells") – Carnivorous Stenostracans with internalized, flexible shells and sharp teeth
    13:33 – Desmostraca ("Bundled shells") – Placostracans with segmented shells and the ability to curl into a ball

    15:28 – Polyschia ("Many hips") – Osteopods with multiple, flexible limb girdles for faster speeds
    15:28 – Synischia ("Fused hip") – Osteopods with one fused limb girdle for supporting larger sizes
    18:27 – Platydontia ("Broad teeth") – Polyshians with claws, long limbs, chisel-like teeth, camouflage in some species, and an arboreal lifestyle

    I will continue this in the future, as I've run out of time right now.

  17. I love learning about these creatures and getting example of how to evolve fictional creatures, but wow some of the visuals are downright disturbing

  18. Again, AMAZING work, this is just phenomenal! It's so rare to see something truely ORIGINAL and well thought out. I can't wait until the next episode!

  19. I'm assuming you will talk about the intelligence development in future episodes?
    And also I had an idea I thought I'd share… if the plants are able to produce a hydrogen gas out of the H2S or the water they could have buoyant pouches. The buoyancy provided by bio hydrogen balloons could be used in a lot of different ways like Seed dispersal, including trans continental travel through jet streams.
    Perhaps even having a completely airborne plant species with eventual flying forests. Again, just a random thought take it as you will.
    I'd like to see tachypodia possibly get a little bigger and possibly be the first to develop wings, the beating of said wings possibly forcing air into their lungs, kinda like how sharks have to keep swimming to pass water over their gills, only they have to keep flying.
    Anyway thanks for th video and keep up the good work, can't wait to see how they develop

  20. What if the inch worm stome used it's expseptional jumping ability to navegate through the crag mountains and evoled to be the world verson of mountain goats

  21. I think that they need lips, a lot animals on earth have lips, and i think lips would help then look less threatening when the don't want be.

  22. I like how everyone in the comments are making non-scientific names for dem creatures
    Here is the list of referances:(these are just my guesses)
    Tree spiders:Dendronomus Vasquezi
    Jumpscare Squids:Elastospondyls
    crustacean cheetahs :Europlos qulielmi

  23. this is by far the best series on this entire website. it's so rare nowadays for someone to not only come up with something this creative, but to actually put real effort into it and keep it going. thank you.

  24. I think some of them would develop extra bits on their mouths to clean up eating and make sure they don't drop anything, like cheeks. Some of them look like they aren't prepared for that.
    I'm very excited to see variations across the continent as they move inwards. Great work so far!

  25. I no longer worry about the antropocene extinction, he will just make enough species to keep everyone occupied.

  26. I am so fascinated by this, I love this video series. I know each video takes a while to make, but I can't wait for part 6.

  27. They keep getting more and more terrifying and less cute i love it …. Also what's happening in the wet place

  28. I hope we will return to the waters and ocians after EP 6 because I want to see how these malaforms colonize the ocian floors as armored crabs,
    How the shark and filter feeder bodyplant evolve and how large they can grow.
    When we evolve to flying and good Mercy inteligent life,
    How sentient lifeform evilvo,
    I I need to gues the polypoda bodyplant will be the first global clade,
    BIG brain, bones, effective breeding, K-selection close cercular system…

    Malaform are will evovle flying,
    In the spawns and the bogs,
    But they are in the deserts and the mediterran biome too.

    Evovle to Therapod life style will paint the way to bird like lifeform.
    Malaform are the base of spider, bug, scorpion, worms, butterfly, dragonfly, water beetle, ant like lifeform too

    They are the first animals where first appier the emergence. Some Stupid things do smart things.
    They weapon is there numbers.

    Feathers, fur, and scales also close to us.

    I live this series and wait for the next ep sometimes 4 mounth left.

  29. Just did something exactly like this for a Worldbuilding project of mine, but dealing with how a pocket of time i.e. multiple creatures from different points in Earth’s history would fit into the same ecosystems. Managed to do an Af wetland biome/foodweb, but holy hell is it tedious work! Especially when accounting for various ecosystems

  30. Re: small creatures being r-selected: what about spider wasps?

    Lifespan: 30 years.

    Reproduction: 1 egg at a time.

    Parental investment: they need to fight a spider much larger than themselves and win, but not kill the spider, sting it, drag it into a pit, close it off in a way that doesn't allow other things in or trap its own child later or kill the spider, and then lay their egg on it. The spider must survive.

  31. 21:47 one could glide further like a flying squirrel

    If only there where some with wing like structures to faster get up in trees, could be mistaken for ears at first

  32. Can't wait to see how they would handle sudden major shifts in climate (i.e glaciation periods, and flood basalt eruptions)…

  33. I wonder if the "landsquid" could evolve so large that it arms can't support the weight and practically flatening Out, resembling more a snail with a big Shell and elongated arms to eat anything that can't escape it's gripp.

  34. I just adore how all of your creatures look so non earth like but still are recognisable as living creatures, keep up the good work mate

  35. Heres an idea: Since we have a tree-dweller who attacks by lunging, make them evolve wings. Theyd spread their legs out to slow their fall, which increases their survivability. Some of the feet would eventually evolve to flatten out, allowing them to glide from tree to tree and fall slower. As their wings grow, eventually, they would grow the musculature and internal structure to be able to fly, either by throwing themselves off a tree or by lunging into the air.

  36. The sarcopod is just this cute little fella scuttling along the ocean floor, then you step on land and come face-to-face with a giant spider with the face of a wolf.
    Jokes aside, it's really interesting to see how the front limbs could become mouths.

  37. I love this series so much. its so intuitive.

    That said, you have to keep in mind the ocean life forms are also diversifying at the same rate.

  38. Yes! Ahhh, I love this. It's so fun. I can't wait to see the new species that will develop in the future.
    Keep up the good work, you are doing great!

  39. This is one of the coolest things I've seen on YouTube. So interesting and we'll researched. Pls keep this series going!!

  40. I love these alien designs! They are disgusting and weird, just like how extraterrestrial life would be in reality. You have excellent job!

  41. the waste processers will probably shrink dramatically due to predatory selective pressure from the bigger species. And some leave searching omnivores may evolve more antenna like tentacles to "filter feed" on the decomposers and they may improve their breathing mechanism with some of these tentacles to grow in size due to predators.
    love the series keep it up! would love to see an episode on the oceans at some point again too 😀

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