Biology  5/e   Raven/Johnson
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The origin of species: Genetically based adaptation to the environment is the basis for selection for survival. Increased survival of better adapted members of a population is the source of new species.

Classification: Three domains are recognized: Archebacteria, Eubacteria, and Eukarya. There are six recognized kingdoms: Archebacteria, Eubacteria, Protista, Fungi, Plantae, and Animalia. Kingdoms are divided into phyla (sometimes called divisions in plants), which are subdivided into classes. Classes are divided into orders, and in turn, families, genera, and species.

Protostomes and deuterstomes: Protostomes form their mouth from the blastopore, and the anus develops elsewhere. Protostome embryos cleave by spiral cleavage. Duterostomes form their anus from the blastopore, and the mouth develops elsewhere. Deuterostomes have radial cleavage of the embryo.

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