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Tree ferns, banana plants, ephiphytes, bromeliads, and other plants growing in a tropical rain forest environment in the Roseau River Valley in Dominica in 2006. While 1.7 to 2 million species have been formally identified, the actual total number of species is estimated to be between 5 million and 30 million.
Photo credit: National Biological Information Infrastructure/Randolph Femmer

Biodiversity, or biological diversity, is the variety of life found in a place on Earth or the total variety of life on Earth. Conventionally, biodiversity refers to three levels of biological organization: genes, species, and ecosystems. Genetic diversity defines biodiversity as the variation of genes within a species. Species diversity, the most common measure of biodiversity, refers to the varieties of species within a habitat or a region and ...

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