Respuesta :
Basically, this might sound as simple as it can be but new species is a whole set of a new classification of an animal or insect like you have never seen it before type thing. And an Old one is probably something that has been around for many years.
( I'm sorry if this doesn't answer your question if not I would like to help you just have to be a bit more specific. And if I did help that's Great :)
"Why new species can not replace the original species. If they both do the same thing what would be the difference between a new species and an old species?"
- This question might be confusing and misleading in my opinon. If you're talking about two different species, they're clrearly not the same thing because they're different.
- Also, there is no such thing as new and old species. They're either extinct or not. But "old" isn't the correct termiinology.
So, if we focus in the second observation that was done above, all we can say it's that it is part of the cycle of nature. Some species go extinct to give rise to new ones (note: only if this occurs naturally). Depending on how you look at it, you can also call it evolution.
Hope it helped,
BiologiaMagister