This is the first time ive heard someone apply the term “Macro-Evolution” to an entire ecosystem of multiple species: in this case it is said that temporarily “changing the ecosystem (by hitting the earth with an asteroid) is Evolution without changing allele ratios.”
And i suppose this is “true enough” for our purposes. But, technically speaking, the only unchanging genomes are for the one or more species going extinct!
For the rest of the surviving species, it should be understood without too much fuss that brand new factors in natural selection are ALSO being unleashed (by the asteroid strike) that could very well affect most of surviving creatures’ allele percentages for one or more traits!
This is exactly what triggered the expansion of various shrew like mammals into new niches previously occupied by larger reptiles.