Introduction

Earth is home to an immense variety of living organisms -- plants, animals, and micro-organisms alike -- and it is this shared diversity of life that makes the planet such a remarkable place to live. Living things are found in almost every corner of it, from mountain peaks to the depths of the ocean, from arid deserts to dense rainforests, and they differ enormously in habit and behaviour, shape, size, and colour. This diversity forms an inseparable, essential part of the planet as we know it -- yet the steadily growing human population is placing serious pressure on it. This chapter works through biodiversity's core ideas -- its concepts, levels, magnitude, and patterns -- before turning to why it matters, the biogeographical regions of India, the threats biodiversity faces, the causes behind its loss, extinction, and finally how it can be conserved.