[Avodah] evolution - new creatures coming into existence 7 days of creation

[Zvi Lampel]

 >.. In Gan Eden there were no such creatures as flies, mosquitoes or 
fleas and other insects that breed in swamps. Only after Adam HaReshon 
was expelled from Gan Eden did he and subsequently, all of mankind 
suffer from this pestilence, which was caused by the tumah of Adam 
HaReshon's sin I am unfamiliar with this midrash - I thought that all 
creatures that exist were understood to have been created during 7 days 
of creation only. has anyone heard this midrash before?<

Since Adam's expulsion from Gan Eden was during the 6th day, there is no 
problem with the principle cited.

Zvi Lampel