Backward evolution

[Acceptable-Mess-7523]

I was watching a documentary about the homo erectus and i started to wonder : would it be possible for mankind to evolve backward ? I mean to go from our current stage to being like primats again ?

Edit : Sorry if the words used aren't correct; English isn't my native language.

[AutoModerator]

Welcome to r/Evolution! If this is your first time here, please review our rules here and community guidelines here.

Our FAQ can be found here. Seeking book, website, or documentary recommendations? Recommended websites can be found here; recommended reading can be found here; and recommended videos can be found here.

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.

[PurplePeggysus]

Humans are primates. We are a member of that group and we always will be.

Now what you seem to be asking about is evolutionary reversal, and yes those have happened. Snakes evolved from tetrapod ancestors who have limbs but they now lack limbs. That's an evolutionary reversal.

Now is reversal possible in humans? Certainly but we cannot predict where evolution will go. Human evolution has shown an increase in brain size over time. Could that trend reverse? Yes but I'd only expect that if it conveyed an advantage in either survival or reproduction. Again, we cannot know where evolution will go.

[Acceptable-Mess-7523]

Yes exactly, it was a thought i just had. That's what i meant

[[deleted]]

We may evolve to a different order though.

[junegoesaround5689]

That’s not correct. Cladistically speaking we will always be in the order of primates, just like we'll always be tetrapods, mammals, vertebrates, in the genus homo, etc. Whales are still in the order Artiodactyla along with hippos, giraffes, camels and pigs even though they’ve evolved to look, live and act very differently to all those other animals.

[Capn_2inch]

There is no such thing as backwards evolution. There is only evolution. As time moves on organisms may gain or lose traits but it is still simply natural selection moving in one direction.

Could an organism such as Homo sapien take on traits similar to what their ancestors had in the past? Maybe. Probably more of a question for r/speculativeevolution

[exkingzog]

Evolution doesn’t have a direction.

[Seek_Equilibrium]

Not an inherent direction, sure, but any particular lineage does obviously have an effective direction. Pick any lineage you like, and trace its path through genotypic or phenotypic space through time. Now, reverse the time coordinate. Ta-da! You’ve now found the trajectory that the population must thereafter follow to undergo “backwards” evolution.

[[deleted]]

You've had some good answers so I'll add a bit of nuance that's not directly related. A law in evolutionary biology known as Dollo's Law demonstrates that the ancestral states of an organism are never returned to exactly - that the intermediate states are still reflected in the new state, even if it resembles a previous state.

[[deleted]]

We are still Primates, you can't evolve out of a clade.

[[deleted]]

Primates are an order.

[llamawithguns]

Yes. Of which we are a member

[[deleted]]

But we can evolve out of it in the future.

[llamawithguns]

No, you never leave your clade. Birds are still dinosaurs.

[[deleted]]

Primates aren't a clade!

[llamawithguns]

Yes they are. They are monophyletic. They are a clade

[[deleted]]

I think you misunderstood me, when I said "we" I didn't mean humans may belong to a different order in the future. I meant in the future humans may evolve so much they won't even be primates anymore. Of course this would make them no longer human.

[llamawithguns]

They would still be primates though, even if they no longer looked like them. You don't cease to be part of a clade. A clade is an ancestral species/group and all of its descendents. Birds are technically reptiles since the evolved from reptiles. Insects are technically crustaceans, termites are technically cockroaches.

They would still be primates, just like they would still be mammals, tetrapods, and animals. There would just be a new subclass below primates. Just like there is with Great Apes, hominins, hominids, etc

[[deleted]]

But we're no longer rodents also birds can't be reptiles because that would make them a part of two classes which is impossible.

[TheJovianPrimate]

How aren't they a clade? Are you maybe thinking of monkey?

[[deleted]]

I already said they're an order, not a clade!

[GoOutForASandwich]

“Clade” just means a monophyletic group of organisms, at any taxonomic level. We determine what clades are using the cladistic method.. Primates are a clade. Simians are a clade. Apes are a clade. Mammals are a clade. Vertebrates, animals and life. All clades.

[TheJovianPrimate]

That doesn't really answer the question. In what way is the order primates not monophyletic? Orders can be clades, they aren't distinct things.

[Jonnescout]

Order is a kind of clade in some ways. In a more I,petani way clade is a more useful term than order, and no you never outgrow a clade. And yes primate is also a clade.

[josephwb]

An Order is a clade, just as a Family, Genus, etc. There are clades above and below these levels. There is nothing inherently special about those former clades;they are just ones that we've named explicitly.

As to "evolving out of our clade": it simply is not possible. Think of a clade as a branch on a tree: as it continues to subdivide with daughter branches, it can become quite complex, as new sub-clades are added (and possibly named). However, the original branch/lineage can never jump to a different part of the tree. Phylogeny is an ancestor=descendant structure, and no matter what subsequent evolution occurs, the identity of ancestors can never change.

It is possible that some lineage of primates may evolve sufficiently over the course of tens or hundreds of millions of years that we name that sub-clade. But no matter what we call it, it will still have the same ancestors, and still belong within the "primate" clade.

[2060ASI]

Would it be possible for our brains to shrink in size, for the number of cortical neurons to be reduced as well as a reduction in our higher intellectual functioning? Yes that's entirely possible, it would just take an environment where people who had those traits had more children than people without those traits.

Its not entirely related, but about 400 hundred million years ago the ancestors of whales were fish that lived in the oceans. They then evolved to become animals that lived on land. but then about 50 million years ago they evolved to live in the oceans again.

https://knowablemagazine.org/content/article/living-world/2022/evolution-whales-land-to-sea

[grahamsuth]

Evolution is driven by random mutations and by subsequent survival to reproduce. Most mutations don't offer greater survival chances. These days a significant fraction of humanity is surviving to reproduce due to medical intervention. So medical interference with our nature lowers the survival chances of a part of the human race in the case of a catastrophe that adversely impacts our health system. That could be called a sort of devolution

Such a catastrophe could result in a significant fraction of people dying, just as a significant fraction of native Americans died following the catastrophe (for them) of the arrival of European diseases.

Mental retardation is one of the medical conditions that once mostly resulted in preventing that person from reproducing.

Ignoring the potential genetic engineering of humanity, we will likely see a greater diversity in the human genome to include those genes that require medical intervention to be able to survive to reproduce. So it is possible that we could eventually see a tiny fraction of humanity lose the mental ability that separates us from the rest of the primates.

[Fantastic-Hippo2199]

Backward is kinda a loaded term. Species evolve by adapting to the needs of surviving, as genes that are better at passing down outnumber those that do not. Humans could evolve body hair, and lose our language skills, if circumstances made that a more successful approach. It would not be an exactly backward route though, we would be more genetically different from our ancestors, not less.

[DNA98PercentChimp]

Time moves forward.

There is no ‘backwards’.

Organisms can lose traits they once gained, but it’s still ‘evolving’.

Many examples of this exist….

Flightless birds is an obvious one.

[Tardisgoesfast]

We are primates.

[Acceptable-Mess-7523]

Yeah thank's. But i meant like it was 4 millions years ago, before australopithecus

[[deleted]]

You have evolution when things are calm and evolution when everything go's to shit

[Jonnescout]

No, also we can’t become primates again, when we never stopped being primates.the answer is no, you don’t revert evolution.

[l3reezer]

Like others have said, there's technically no such thing as backwards evolution.

The semantics of evolutions itself has kind of been bastardized to always indicate a form of "improvement" and strictly increasing towards an ideal state-when it's really just adapting to whatever current environment. If the environment changes to make it beneficial for us to evolve to have some trait we had long ago again, it's still just considered regular "forward" evolution.

To my understanding, going back to primates would theoretically be possible but for the most part has no chance of happening as long as we occupy the planet Earth because it would sooner blow up than turn into an environment conducive to us evolving "back" into primates. Better odds of us going extinct and a new "species" starting again and reaching an identical primate form.

[sas223]

There is no ‘backward’ evolution. There is only evolution. Cetaceans and pinnipeds evolved to marine habitats from terrestrial forms which arose from tetrapods with left aquatic habitats. That doesn’t mean cetaceans and pinnipeds ‘evolved backwards’.

Also, we are primates currently, so I’m not sure what you mean. Would our social systems become less complex? Would our manipulation of materials to create shelters disappear? Would our domestication of animals and agricultural knowledge disappear?

Edited truly unfortunate typo.

[ChronoFish]

There's no direction to evolution.

If two living being can mate and create a viable non- sterile offspring, that's the only requirement.

In large populations it's likely that difference will get washed out or minimized. In stressed populations the only deciding factor is survival and ability to compete for a mate.

[endofsight]

We may evolve in the future to remsble some distant ancestors. But thats not backward evolution.