Ratites are often described as having a ‘Gondwanan’ distribution because they are currently only found on the southern continents that once made up Gondwana (See Figure 1). It has been hypothesized that the common ancestor to all ratites originated in Gondwana and dispersal of this group of flightless birds occurred with the breakup of this ancient supercontinent (See Figure 7レ Tinamous Rheas and Tramous ■ Ostrich 160 Ma Equator 120 Ma Terhys Sea Gondwana TRIASSIC 200 million years ago 80 Ma Figure 1. Top photo shows present day configuration of the earth’s continents. Coloured/shaded portion of continent reveals extant ratite species distribution. Bottom photo shows hypothesized configuration of earth’s ancient supercontinents, Laurasia and Gondwana. 200mya (million years ago). 50 Ma Diologyr How Life Works, Geeond Edition 2018 wuL Freeman and Company Figure 2. Photos show theory of how continents drifted from 160mya (top) to 50mya (bottom) Coloured/shaded portion shows how southern continents drifted, or the breakup of Gondwana