Can anyone help explain the time theory

Hi, time theory is the theory laid out in the second paragraph. It is effectively that tropical species have had more time to adapt and emerge since they have had a longer time to exist in the tropics. To the north and the south the ice ages impacted species, and in some cases would have effectively made life almost impossible in some places. However this was not true in the tropics. So, species in the tropics would have been able to just go on living and evolving while this was not the case in colder climates.