gobble_ghoul [he/him]
Feel free to cite your source. If you’re thinking of the idea that chickens may have more conservative genomes than most other birds, then I get where you’re coming from, but we don’t actually know what T. rex’s genome looked like to be able to compare them. It’s entirely possible that the T. rex genome would have changed in a lot of places where the chicken genome is relatively conservative, making chickens no more similar to T. rex genetically than any other bird is. That aside, all birds evolved from the same node on the cladogram, which was already pretty far removed from tyrannosaurs at that point. Saying chickens are more closely to T. rex than other birds are would be like me saying I’m more closely related to my great uncle (whose DNA we do not have) than my biological sibling is because I have 25.01% of his brother’s - my grandpa’s - DNA and my sibling only has 25%. It’s not provable because we will never recover the DNA to know the overlap. Even if we could prove that, it would only demonstrate that we are more related in a very strict genetic sense and ignore that we are exactly as related in terms of shared common descent.
That’s not how it works. All birds share a common ancestor that was a cousin to it, so they’re all equally related to it in terms of when they split off. For chickens to be more closely related to T. rex, they would have to share a more recent common ancestor with it than they do with other birds. That would also make T. rex a bird if you still wanted to count chickens as birds.
It’s decent for a few hours of fun. Not super long and I wish that they had worked in a lot more interesting environmental and Pokemon interactions for the player to trigger, but I enjoyed it. Hopefully we don’t have to wait 20 years for the next one and hopefully it’s more ambitious if and when it does come out.
The snake and lizard branch is wrong. I care very much about the accuracy of memes, and I have to point out that many lizards are more closely related to snakes than they are to other lizards.
There are multiple different concepts for defining species. The long and short of it is that species are not a fact of nature but a useful construct for us to be able to describe it.
Some other factors that are used to distinguish species:
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- The organisms are biologically capable of reproducing, but their genitals are incompatible and prevent it from happening outside of a lab setting.
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- A behavioral difference prevents individuals from different groups from reproducing. For example, several bat species have recently been redefined as multiple species by scientists because they’ve found that they communicate at different frequencies and they aren’t always even capable of hearing the other group’s communication. So even though they can interbreed, they don’t.
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- Geographical separation combined with physical and/or behavioral differences. If two groups never interbreed and you can consistently distinguish them from each other, it might be worth considering them separate species. This comes into play a bit more when it comes to conservation efforts because there is incentive in labeling a unique population as its own species, in order to make it more apparent that the group is endangered even if it is technically capable of breeding with another group that isn’t endangered.
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- Two groups are capable of interbreeding, but have enough differences that hybrids between them are less fit and tend to die before reproducing even if they are fertile. If you have a population of lizards that is good at swimming but bad at climbing and a closely related population that is good at climbing but bad at swimming, their offspring might just be bad at both and struggle to get food. Even if they regularly reproduce with each other, the genetic impact of that on either group is negligible because only the non-hybrids are making babies.
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- Morphological differences. If two things just look really different, we can call them different species. This is especially true for organisms that don’t reproduce sexually and for fossil species. There’s no way to test if a Tyrannosaurus could have a baby with a Velociraptor, but odds are it couldn’t. Truthfully it gets even more complicated with fossil organisms and can sometimes come down to scientists saying “the ankle bone developed a little knob around 76 million years ago and 10 million years is a long time to be considering these fossils all of the same species, so we are going to use that ankle bone knob as a marker of a new species distinct from the species without the knob that came before it”.
