First of all, cephalopods are most certainly not alien any more than you or I are. Although their biology is radically different from vertebrates down to the way their nervous system is organized and the metalloprotein used for oxygen transport, at the cellular and genetic level they are clearly on the same continuum as all other animal life on Earth. They represent the diverse potential of evolutionary biology in finding a wide array of different ways to develop complexity in biological systems to adapt to different environments.
As far as we know, the origin of life on Earth is not an anomaly; lacking any data about the frequency of occurrence life anywhere in conditions suitable to support biochemistry as we know it, we cannot make any statistical inference about whether the timeline or prolificacy of Earth life is special. The only worlds with any kind of atmosphere and a terrestrial surface that we’ve studied to date are Venus, Mars, and Titan; the atmosphere of Venus would be immediately toxic to any life we would recognize, and the harsh UV and near vacuum conditions on Mars means that any life that could exist would be subsurface and and subsist upon unknown energy mechanisms. Titan is rich with hydrocarbons but frigidly cold and without sunlight, so energy would have to come from some kind of chemosynthesis driven by tidal heating, and of course we’ve barely scratched the surface or that world or the other water-rich moons of Jupiter and Saturn.
However, if the basic chemical organization and biochemical mechanisms of life are not extraordinary (there is nothing about life at the molecular level that is outside of normal organic chemistry as we understand it and the fundamental precursors of life, amino acids, are found in the interplanetary and interstellar medium) the Law of Large Numbers and the shear number of potential reactions would suggest that given suitable conditions that life would almost inevitably arrise quickly in a primordial substrate with a continuous source of energy. The question of abiogenesis may be less one of how quickly life on Earth developed as much as what rare bottlenecks lead to the kind of complexity that we observe and whether they represent an obligatory path (e.g. the development of energy-processing organelles within cells, the division into sexual reproduction, the adaptation of complex sensory processing networks into cognitive structures, et cetera). There is no particular need for the panspermia hypothesis to address the question of the abiogenesis or development of life, and even if there were it would merely displace those questions to another location.
[quote=“Yllaria, post:18, topic:814457”]
To expand - when Continental Drift was proposed, there was no known mechanism that could have caused it. The discovery of Plate Tectonics came later and proved to be the mechanism.
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Although the hypothesis of continental drift was not widely considered credible prior to the verification of plate tectonics, there was always a coterie of geoscientists and paleontologists who held that there was sufficient evidence in the geologic and geomagnetic record to indicate the movement and reshaping of continetns. The lack of a credible mechanism that could move such vast masses (and at the time, at rates that were estimated to be a couple of orders of magnitude faster than we know them to move now) hobbled the acceptance. This isn’t so much an example of a “loony idea” as one that simply didn’t have a known physical mechanism to make it workable.
They are also not very social animals (though many species of squid will swim in shoals while in a feeding frenzy) although it is clear that they can communicate and in surprisingly sophisticated ways with other octopus. Marine zoologists who have studied octupuses have had to continually revise their estimation of their spatial and social intelligence upward as they learn more. Probably the real limitation for the evolution of cephalopods is one of energy; being largely stuck in the ocean (although they have been known to climb out onto land to raid tidal pools, or escape from aquarium tanks to feed on other creatures) any advanced technology beyond stone tools would require some alternative to fire and hot smelting, such as enzymes capable of breaking down minerals in an ordered fashion, or structures ‘grown’ like coral reefs. There are bacteria which can do this for individual oxides and metallic carbonates, but some kind of advanced biochemical-based technology that could provide analogues to human industrial technology are so radically different from anything we use that it is hard to envison a detailed workable system.
In any case, octopuses are not aliens (and not even the strangest creatures in the ocean, by far) but they do represent just how varied life from a common origin can develop given time and evolutionary pressures to adapt to specific environments. That alone gives reason to believe that if the conditions for life are at all common, that complex life likely develops as a matter of course.
Stranger