"There is a fork on the ground."
Translation:На земле вилка.
I'm not a native speaker, so perhaps this might be wrong, but the way i figure it "На земле есть вилка" would means "The ground as a fork" where i think the "fork" if the new information so it goes at the end - На земле вилка (On ground, Fork). That's how I see it anyhows, hope it helps
Though very similar, adding "там" seems to give the sentence a hint of "over there", like pointing. The original sentence simply states "There is a fork on the ground", not implying the "over there" part. The fork might even be right here next to my feet, as long as it is on the ground.
Adding to this, note that the English "there" used in the sentence is not really meaning "there" as a place (там) but the English phrase "There is" or "There are" works as a single unit expressing existence/presence. That is, you don't say "Is a fork on the ground." or "Are many people in this room". You use "There is" or "There are" for this meaning.
Земля (nominative case) comes from proto-Slavic "zeme", which comes from Proto-Indo-European "dhegh-om" meaning "earth", which went through Latin to give English "humility" or "humiliate".
So the "зем" in Russian is related to the "hum" in English; languages are wild.
I think of the Proto-Indo-European root as "dig", but I don't think that's actually a connection.