The archaeological record consists of physical
objects that have been shaped by human contact.
These include not only tools, ornaments, and pottery,
but also soils, waste deposits, houses and landscapes.
The earliest recognizable stone tools date from about
2.5 million years ago (MYA; see Section 8.3). Humans
are not the only animals to make tools, but tools
produced by earlier human ancestors or nonhuman
species are difficult to distinguish from naturally
occurring objects.