It is extraordinary how increasingly complex the tree of life appears the more you actually look at it. I never imagined at first I would come across things such as 'unikonts' and 'Opisthokonta' and 'Apoikozoa', and I had no idea I would discover so many unknown, unranked grey areas where plants, animals and fungi all seem to blur with things that are not quite animals, plants nor fungi. Check out the progress so far if you haven't already:
So last time we looked at Ediacarans and the start of complex life. Nobody is exactly sure but the movement from single celled life to multi-celled life may have come from competition on floorspace with lots of organisms clumping together in a blanket across nutrient rich floors before symbiotically working together.
Evidence of this may come in the form of Ediacaran life found in fossils as flat, complex organisms, but the debate continues to this day.
The main quandary in this idea is why: Why bother becoming multicellular when life being single is clearly beneficial, having had a lifetime 2 billion years over multicellular life. There is nothing in the birth of multicellular life that suggests ditching the group and doing their own thing is a bad idea. In fact, the very idea of abusing the system and benefiting more as a singular item seems biologically tempting indeed.
According to NASA:
...a group of microbes that secretes useful molecules that all members of the group can benefit from can grow faster than groups that do not. But within that group, freeloaders that do not expend resources or energy to secrete these molecules grow fastest of all.
Cancer is a classic example of single cells thriving in a way that f***s it up for everybody else.
But this behaviour is even seen in complex life, such as cuttlefish. Earlier on Steemit I wrote about how a certain percentage of cuttlefish actually steal mates from bigger cuttlefish with clever deception, but if caught they can be in a world of trouble. In this case, the risk-reward ratio must have balanced out so that only a certain number of thefts would be tolerable before things started breaking down in their society. The same could arguably be applied to Humanity.
In the case of single celled life, it seems likely that they actually took advantage of team work and lone-wolfing the situation. There are examples of bacteria today that work together to create a thriving society, but then collectively cheat the system by not putting in the effort once they feel it's not necessary for themselves. Once they all decide that, the colony just... dies.
You may notice the fatal flaw in these lifeform's methodology. I'll give you a second to take a guess...
Got it yet?
Last chance....
The problem lies in their uniformity. If everybody is doing the same job, the responsibility is diluted among them and each individual starts backing out when they feel it's safe to be lazy. Think of it as the earliest form of Socialism.
What appears to happen, through mechanisms unknown as of yet, is that different tasks started to be handed out to different members of the colony, making each of them mutually dependent on one another. This way, those who slack off instantly get noticed and everybody including themselves start to pay the consequences. The group may only be stable if everybody is pulling their wait in their individual assigned tasks.
The added benefit of this is that there is a forced forward momentum in complexity, with a minimal risk of reversion. This is described as a ratcheting mechanism, which allows momentum of machinery in one direction, but not the other
This process gets much more complicated than it sounds, involving G and I cells, and strange equations that look like this: 
which you can explore more in the sources below.
Needless to say, evolution found a potential mechanism that for the most part punishes solo activity and promotes teamwork, and this may have been the very first example of Symbiosis in nature - long before the often cited mitochondrial-cell symbiosis with which we all live with today.
As complexity increased, more jobs would have been divvied up through the generations until you basically end up with modern life; vast biological factories of cells divvying up odd jobs to keep the machines working.
So where to next?
Now we've crossed the main hurdle after a mere 2 months since I started this series, we can continue down the tree to more substantial, visible organisms: Animals.
We first pass the most basic forms of this life that seem somewhat reminiscent of their bacteria blanket ancestors, including sponges (7,500 known species), Placozoa (ONE lonely, lonely species), Comb jellies (167 known species), and Jellyfish & Corals (15,000 known species).
But this is where we see a significant feature:
Bilateria
Bilateria is a feature in animals that show a clear bilateral symmetry within their bodies. Everything from this point will share this feature that all previous organisms lacked. But why? Why is bilateria so significant that it consists of 1.35 million species?
Find out next time!
References: NASA | Stabilizing multicellularity through ratcheting | Ratcheting the evolution of multicellularity | Bilateria
Image Sources: Virginia Tech | all others CC0 Licensed
Mobbs, I think you very nicely addressed the question why did natural selection eventually lead to the emergence of multicellular life forms. But personally I think the question that started the post is kinda clunky and misleading. Evolution does not choose anything and the question might cause someone to think of that conclusion.
The real question that I see being asked and needing to be answered is why did the processes of evolution require 2 billion years to form the first multicellular life? Why did it take so long? My approach to addressing this question is to recognize the limitations of our knowledge. We do not know what he first multicellular life looked like, but it probably looked something like a slime or a colony of small cells. We do not have a good representation of the life on earth 2 billion years ago because we are limited by what we find in the fossil record. This limitation is a barrier. And likely the first multicellular life did not have properties that would allow for frequent fossilization that would survive 2 billion years of earth's history.
I am not saying that scientists and researchers should quit at this point, but I am acknowledging the tremendous difficulty associated with obtaining evidence of the past from so long ago. Looking forward to the next episode in your series.
Whenever I see the word "evolution" followed by a verb I get upset.
"Evolution created..." NO!
"Evolution designed..." NO!
"Evolution chose..." NO!
Nothing wrong with a bit of casual anthropomorphism in a title for readers' interest! I don't think anybody would misconstrue it as a conscious effort by evolution if that's what you mean?
Regarding the time taken, fossil records are not the only way to figure these things out; it's amazing what we can do with genetic analysis for example. That being said I can't say I'm an authority or anything at all really but I do know that it's possible that multicellular life did in fact occur much earlier, but never succeeded; there's know way of knowing of course but the fact is it was a huge hurdle for life to take, and unlikely it would have just worked first time round.
In fact, as far as we have evidence for, endosymbiosis only ever happened once (up to the prokaryote stage of life, that is), which itself implies the massive undertaking of chance that must have gone on.
Time is a funny thing; 100 years ago people would have laughed at the idea of people walking around on the moon, but now we consider it an ancient, 50-year old party trick. At the same time, humans walked around doing a whole lot of nothing for tens of thousands of years.
Human perspective can add a lot more disbelief to a perspective than necessary because that's how our psyche is designed... but this is more philosophical than I had planned in this comment
Mobbs, you haven't met some of the evolution deniers and their ilk like I have. Anything that they can construe as a vague nod or wink to their position they will run with. That was my concern. You are totally correct about human perspective. We can only speculate how it will change as our knowledge grows and future technologies take hold, like AI.
Although once a being is able to think and feel things, it stores that conscious info within it's DNA, so evolution of how the structures evolve when born isn't chosen at the time, but it does get decided by/from a conscious decision that stems from the previous living parent being.
Very unlikely @grottbags. But there is a something called epigenetics where environmental influence can modify an organism's germline DNA and therefore affect subsequent generations, even altering their behaviour. The effects of starvation in humans and worms have been shown to have epigenetic effects.
Cheers!
ian
I find this extremely unlikely to be true. You should write a post about it if you think you have evidence... for a start 'think and feel' is a vague term, as if both 'thought' - whatever that is - and 'feelings' happened simultaneously.
From my understanding, learned traits that may appear to be passed down refers to unconscious 'skills' such as resistance to viruses acquired during a lifetime. This has possibly been mixed with the reports that memories can be stored in DNA, but this is more referring to specific actions happening when specific synapses fire to lock that information in, or perhaps when stress affects and shapes DNA or other information.
There's no such evidence that some conscious, tangible thoughts can be directly passed from one to another. But again if you can find evidence of actual conscious thoughts being passed via DNA, you should write about it, I feel it would be some groundbreaking discovery
Nice reply @mobbs!
If I remember correctly, the only evidence that vaguely resembles thoughts passed via DNA or cells is a paper in 2013 that showed Planaria ( flat worms) are capable of remembering events that happened prior to having its entire head removed. This seemed amazing to me at the time and I am not sure if it has been reproduced.
Cheers!
ian
I wasn;t meaning actual conscious thought being the things that are passed along, but the alterations in our emotional behaviours caused by conscious awareness do get stored in a format to pass along later.
If you spend a life continuously stressed. You could be stressed at a million different things and reasons, but when that converts into the body, it is just registered as increased hormones and decreased emotional aspects.
A baby that is born from a stressed out emotional wrecked being, receives some of that via it's DNA. It is why some babies are more prone to having mental health disorders than others. This babies have this pre-programmed stress, if the environment is good it may never comes to light, if the environment is stressful, the pre-programmed stess info within the DNA comes to light making that baby act different compared to a non-stress chain of babies.
But point is, it will all be caused from the conscious processing from the parent that creates the stress in the first place. It wouldn't remeber the exact thought the parent had, but it will have a feeling that it does or doesn't like something and therefore act accordingly with know real thought or direction other than sub-conscious... which i believe the subconscious to be the work of our cells and their "memories"
I will try prove myself better as I go... I dont think science has done enough yet for me to find the answers im looking for, whether to confirm or disprove... will see though :D Always interesting the think
on the contrary, science has done enough in this case since you're actually just describing what we two have responded to you with, so it seems we're more or less on the same page here
Well written buddy. The concept of evolution is so complex that we can only understand them in phases. But with the help of fossils, it would be better understood :)
Someone once said "the more you know about evolution, the more you discover you know very little" :p
Thanks for sharing buddy. I've learnt new things again
That quote can be applied much more generally in this handy graph:
Lol. Absolutely.. I agree with you 100% :)
We have good explanations for every step of evolution towards more and more complex organisms ... but at the same time we shouldn't forget that microorganisms (as well as comparable simple multicellular organisms) are still very successful participants in the big game of evolution (for example in terms of the number of living individuals or biomass) ... :)
For sure. In fact I'm pretty sure there's more total biomass in microscopic form than macro... yeah a quick google shows there's up to 550,000,000,000 tonnes of bacterial biomass alone, compared to under 500,000,000 of human... phew!
Worth a post in itself, I think, they deserve the credit =)
Why is life coming from things that are not alive relative to time??? Because it is unobservable, so they tell you millions and billions of years to cover up that fact... Observe entropy, how things decline over time... Also we can observe the moon we can observe Mars, with no life but the life on Earth it cannot be hidden... Go by whats observable, do your own research and challenge EVERYTHING!!!
Not quite sure how this is relevant? I don't understand the first half of the comment. 'they'?
"they" refers to anyone who uses Billions of years to jump from a theory of how it was to how we observe something is today... As for how it is relevant, I feel that question and statements I posed is at the heart of this article, the assumption of evolution.
There is no doubt in the fundamental foundations of reality that evolution is a thing =/
If you don't trust 'them', you are, like anybody else, absolutely free to 'question everything' and do the experiments yourself. But I can speed up the process and tell you you'll end up with the same results