Wow..a lion to tiger in 4 million years and chimpanzee to human in 7 million years. Something doesn't seem to add up.
The only thing that doesn't add up is your sentence.
Lions did not become tigers they evolved from a common ancestor, Humans did not evolve from chimps, they have a common ancestor.
(note) try reading
The Ancestor's Tale, by Richard Dawkins
As for whether it is 4 million or 7 million or 50 million matters not. Evolution follows no time table.
Edited by bluescat48, : missing "i"
Edited by bluescat48, : dis for did
There is no better love between 2 people than mutual respect for each other WT Young, 2002
Who gave anyone the authority to call me an authority on anything. WT Young, 1969
Since Evolution is only ~90% correct it should be thrown out and replaced by Creation which has even a lower % of correctness. W T Young, 2008