There is a chicken/egg misunderstanding from all sides about evolution, that because, we (humans for example) evolved from other apes, monkeys (similiformes), primates and mammals etc. that this means a non-human once gave birth to a human. This has many implications beyond biology of course. But this is in fact not the case. If you were to go back and observe actual real time events, this is a scenario you would and could not experience. Taxonomically of course, the egg came before the chicken, because eggs pre-date chickens.
“No non-human has ever given birth to a human, and all humans will only ever give birth or rise to humans.”
This may seem like an irreconcilable contradiction, but the square can be rounded. Because it is a real square circle, and the fuller realisation happened quite recently for me, by way of a respected member of the PEP Facebook group.
First, many of us have been tricked or fooled by some misused words, like intermediate, gaps, transition, macro/micro evolution or missing link. By using them, we can easily be forgiven for reading into them, seeing implications or believing them.
The problem is, they imply a stepped process or clear distinctions, when the reality is a smooth and seamless spectrum.
Speciation though, is a population issue. A new species is a group, perhaps separated and sufficiently genetically different so as not to be able to interbreed any longer with its direct ancestors. They (or it) will always be able to reproduce with its parent or child and relatively close family, (and therefore is the same species) probably for centuries or millennium, or with relatives that are still alive, but separated by some time and/or geography.
As a species is something which is different from its predecessors (largely being unable to interbreed, largely by definition), then a parent is not a different species to its offspring or parents. This alone demonstrates that one species (e.g. a non-human ape species) cannot produce a human, or vice versa. Not directly anyway. Only time and/or geographical separation and/or genetic non-viability through change can make new species.
So, the concept of a non-human producing a human occurs in population changes, not in individuals. You could not go back in time and observe an individual or couple, where its/their parents or offspring were a different species.
It may be that, depending on definitions, Homo sapiens sapiens are the same species as gorillas or chimpanzees or bonobos and delegate a sub/sub species delineation. How so? Well it hasn’t been decisively proven one way or the other, whether viable offspring are possible. But we could define species by traits other than an ability to be inter-fertile.
At what point did you evolve from your younger self?
By way of a comparable example, if you take incremental photos of a human being between birth and death, and show them to a stranger at set (say, ten year) intervals, each will be unrecognisable from the other, to outsiders. But a close family member who sees the person on a daily basis, will see no change. Two perspectives but only one thing occurring.
What do the missing links look like? Their parents and children.
To state, suggest, imply or believe that a reptile turns into a mammal or similar, is to misunderstand, deceive or lie and mix up short term with long term events. A desolate river bank turns into a bustling city hub, but not if you stand and watch – it takes centuries or millennia to occur. The difference from A to Z is huge and unrecognisable on a macro scale, if the increments are big or long enough. But any single change or passing second will look almost identical to that immediately or shortly before or after – like evolution or the seamlessly incremental development of a single human being from birth to death, when observed in real time.
A reptile and a mammal are largely very different in many ways. Quite often, it isn’t that a modern mammal had to have had intermediate looking ancestors to a modern reptile, like a direct line, filling in the, ‘gaps’ to try to imagine what it might have looked like, or putting a fanciful reptile head on a mammal body. You can’t pick a random mammal and a random reptile and assume there must be things that now (or once) look(ed) like something in between. Evolution does not work that way. It is more a case of looking back over their very different looking ancestries until we find a common genetically viable link from where they sprung and split into lineages, by micro/speciation events. So many people do not, but need to, understand this. Mechanisms in evolution are sometimes hard to grasp or explain and it is the duty of educators and this project, to bring this understanding in an understandable, exciting way to the masses.
An alternative way to understand, is to ask, ‘at what exact point does a baby turn into a child? A child into a youth? To an adult? At what point are we old? The baby is clearly VERY different from the adult, but it is just about scales, and when they are so big, and we are absent for so long, it seems unbelievable.
Not quite from a frog to a prince.
If we show a 12th C person a computer, phone, camera aeroplane or car, it will seem supernatural and/or impossible. We may well be equally confused by something brought back from the future. This is all because we cannot imagine the progress that can be made.
To even mention that evolution turns goo (or worse, rock) into people, or anything that suggests that anything occurs that is beyond the capability of nature, is to be lazy and attempts to emotionalise and bring the macro onto a micro scale. To miss this perspective is to deliberately deceive. Caterpillars turn into butterflies, zygotes and then babies turn into old people and a single celled organism turned into a person. It’s just about the scale of things.
With regard to the post image, have a look at Lincoln Park zoo, gorilla birth and see what you find. The unedited photo was taken there, along with many others. Baby born 12th May 2019. Mother and baby doing well. Strong light can be deceiving. You can zoom into this image too, which might help.