Some places parallel universes are connected... And it's possible to jump between them, Golden compass, back to the future, looper, lost are some egs
There are at least two reasons why life might look similar everywhere... One is panspermia, that universe is full of dormant bacteria that cause life to spring up in any habitable zone planet that gets bombarded by rocks and comets. Another is convergent evolution, life tends to find similar solutions to environmental obstacles. Eg: camo in grass means stripes for both tasmanian tiger and bengal tiger.
If exotic life exists (gaseous life forms on jupiter like planets, nebulous ones in free space, silicon or arsenic based) then we should be seeing a lot more evidence, but we barely have any for carbon based life only