The Land is the next frontier that some clades 'choose' to conquer. The land offers lots of niches for these animals, which may look to get away from the competition in the seas. The first terrestrial organisms were Symbiotans, a kingdom of mostly large, hyper-symbiotic, colonial organisms, which are entire environments in and of themselves. These came onto land around the middle Siadorian period, 430 million years ago.  During the Karbonian period, A multitude of clades from the other kingdoms came onto land, right after the 1st Kerbinian mass extinction event. Several periods and 2 other mass extinctions later, and Kerbin's terrestrial fauna today consists of mammal-like organisms, giant flyers, and a myriad of other organisms. 

The Continents have seen some changes, since the first terrestrial animals evolved, from a large, central supercontinent, to three continents, and back to a supercontinent.  And today Kerbin's land mass consists of a supercontinent spanning the entire planet, with loads of biomes for organisms to colonise. As mentioned previously, the continent between Kafrica and the Loveheart Ocean harbours a large desert, which is a haven for coastal Symbiotans. This arid climate in the desert is slowly, but surely humidifying, as these Symbiotans begin to grow old. The continent to the west of the Loveheart ocean and the east of Kafrica, harbours a fairly humid climate, with a large tropical rainforest on its eastern side, provided by Tropical cyclones striking from the ocean. This climate facilitates the highest diversity of organisms anywhere on Kerbin.  On a more open scope, Treelands, a type of woodland characterised by evenly but distantly and randomly spaced trees, are widespread on Kerbin, along with grasslands and occasional forests.