生物短文

Biodiversity（生物多样性） is the totality of genes（基因）, species（物种）, and ecosystems （生态系统）in a region.

The wealth of life on earth today is the product of hundreds of millions of years of evolutionary（进化的） history. Over the course of time, human cultures have emerged and adapted to the local environment, discovering, using, and altering local biotic resources（生物资源）.

Many areas that now seem "natural" bear the marks of millennia of human habitation, crop cultivation（耕作）, and resource harvesting（收获）. The domestication（驯养） and breeding（饲养） of local varieties of crops and livestock have further shaped biodiversity.

Biodiversity can be divided into hierarchical categories that describe quite different aspects of living systems that scientists measure in different ways.

Genetic diversity（遗传多样性）
Genetic diversity refers to the variation of genes within species.

This covers distinct populations of the same species (such as t