Reactions to On the Origin of Species stage where he was able to turn his attention fully to "Species", and from this point he was working to publish his theory. On 18 June 1858 he received a parcel from Alfred Russel Wallace enclosing about twenty pages describing an evolutionary mechanism that was similar to Darwin's own theory. Darwin put matters in the hands of his friends Lyell and Hooker, who agreed on a joint presentation to the Linnean Society on 1 July 1858. Their papers were entitled, collectively, "On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means
On the Origin of Species America, Africa, and Australia all have regions with similar climates at similar latitudes, but those regions have very different plants and animals. The species found in one area of a continent are more closely allied with species found in other regions of that same continent than to species found on other continents. Darwin noted that barriers to migration played an important role in the differences between the species of different regions. The coastal sea life of the Atlantic and Pacific sides of Central America had almost no species in common even though the Isthmus of Panama was only a few