. Animal Ecology. Animal ecology. FIG. 21-1 North America dur- ing the early Eocene, showing the configuration of the con- tinent (tinted area, superimposed on an outline of the continent at present) (Schuchert 1955), and floral units (from information given by Chaney 1947). The Madro-tertiary flora was begin- ning to differentiate in small scattered areas within the general area Indicated (Axelrod 1958). Madro-tertiary flora The Madro-tertiary flora had its center of origin on the plateau in the region of the Sierra Madre, perhaps beginning in the Eocene in scattered dry sites on the
. Animal Ecology. Animal ecology. FIG. 21-1 North America dur- ing the early Eocene, showing the configuration of the con- tinent (tinted area, superimposed on an outline of the continent at present) (Schuchert 1955), and floral units (from information given by Chaney 1947). The Madro-tertiary flora was begin- ning to differentiate in small scattered areas within the general area Indicated (Axelrod 1958). Madro-tertiary flora The Madro-tertiary flora had its center of origin on the plateau in the region of the Sierra Madre, perhaps beginning in the Eocene in scattered dry sites on the lee sides or rain-shadows of high ridges and mountains. Its history previous to the Miocene is obscure. The flora contained a variety of small trees, shrubs, and probably some grasses, although the fossil record of grasses is poor. These species seem to have been derived principally from the Neotropical-tertiary flora in response to increasingly arid environments (Axelrod 1958). Minor elements of this flora extended into the Great Basin area, but its main movement northward oc- curred in the Miocene and Pliocene. During the latter epochs, the flora came to occupy large areas in southern California, the Great Basin, and the Great Plains, areas which were being vacated by the other two Tertiary floras because of the increasing aridity. Derived in large part from this flora are the present- day communities of woodland, chaparral, sagebrush, subtropical scrub (thorn forest), desert, and arid grassland. These communities are relatively young, as distinct entities ; the North American desert biome, for instance, is probably not older than Upper Plio- cene (Axelrod 1950). Paleo-ecology 283. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Kendeigh, S. Charles (Samuel Charles), 1904-. Englewood Cliffs, N. J. , Prent
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Keywords: ., bookcentury1900, bookcollectionbiodive, booksubjectanimalecology
