More species are of no direct benefit to humans. Some habitats have more species than others. Biodiversity includes genetic diversity, species diversity and ecosystem diversity. Biological diversity is more threatened now than at any time in the past 65 million years. The loss of forest, wetlands, grasslands, and other habitats contributes to loss of biodiversity.
Many species become extinct without ever being identified.
Large plants, birds and mammals make up about half the world's species. The countries with the most species of vascular plants are located in Central and South America and in Southeast Asia. Coral reefs are as rich in biodiversity as tropical forests. Many islands are home to species found nowhere else. Fewer than 100 species currently provide most of the world's food supply.