We obviously are operating with an extremely limited dataset (currently of size "1"), but there are a few things we can look at that may tell us something about the likelihood of particular characteristics evolving.
We know that flight has evolved on Earth at least four completely distinct times (no common flying ancestors): birds, bats, bugs, and pterosaurs. The basics of eyes are thought to share a common ancestor, but complex image forming eyes are thought to have evolved dozens of times.
I'm sure there are many better examples; I have only studied biology in my spare time as an adult, so maybe a biologist can step in.
The basic idea though is that since the driving force behind the change is not random certain general ideas are likely to keep on popping up over time. Now, are the building blocks likely to be the same? Hard to say, the chemistry for carbon based life works particularly well, but there are hypothetical alternatives. I can't speak to which is more likely than the other.
The question of "how likely is this" is really quite involved.
We obviously are operating with an extremely limited dataset (currently of size "1"), but there are a few things we can look at that may tell us something about the likelihood of particular characteristics evolving.
We know that flight has evolved on Earth at least four completely distinct times (no common flying ancestors): birds, bats, bugs, and pterosaurs. The basics of eyes are thought to share a common ancestor, but complex image forming eyes are thought to have evolved dozens of times.
I'm sure there are many better examples; I have only studied biology in my spare time as an adult, so maybe a biologist can step in.
The basic idea though is that since the driving force behind the change is not random certain general ideas are likely to keep on popping up over time. Now, are the building blocks likely to be the same? Hard to say, the chemistry for carbon based life works particularly well, but there are hypothetical alternatives. I can't speak to which is more likely than the other.
The question of "how likely is this" is really quite involved.