Fossils and threats to biodiversity

Fossils are the preserved remains of plants and animals in layers of rock, sand and mud. Generally, deeper, older layers hold simpler living things, and newer layers hold more complex ones. Fossils are nature's history book. Important fossils, from dinosaurs to early humans, have been found in India.

Birbal Sahni studied fossil plants and founded the Birbal Sahni Institute of Palaeosciences in Lucknow. His work linked today's plants to their ancient ancestors.

Names can honour places or people. The purple frog, *Nasikabatrachus sahyadrensis*, is named after the Sahyadri hills (the Western Ghats). It lives underground most of the year and comes up to breed in the monsoon. Its discovery in 2003 told scientists about an ancient family of frogs.

Biodiversity is in danger. Human activities are reducing it:

• pollution;
• cutting forests;
• using up natural resources;
• climate change.

Living things depend on each other, so when one species disappears, others that depend on it may decline and disappear too.

A story from Manipur. In Loktak lake (Keibul Lamjo National Park) float grasslands called *phumdis*, from a few centimetres to two metres thick. They are home to the Sangai, the "dancing deer", found only in Manipur. It was declared extinct in 1951, then found again in 1953. Today the phumdis are breaking down and the Sangai is on the IUCN Red Data list of threatened species. Saving its home is the only way to save the deer.