The growing fossil record and detailed genomic evidence provides an increasingly detailed understanding of our ancestry and geneology.
Fossils and lost tools recovered from the geological record give us hints as to what kinds of humans were present in particular geographic areas. Various forms of dating based on the decay rates of a variety of different radioactive elements together with geology and stratigraphy tell us when they were there. This record grows more detailed through time as more paleoanthropologists study more areas in more detail and as Moore's law speeds up the publication cycle.
Enabled by the application of Moore's law to automated gene sequencing technology, over the last 5 years the detail and volume of genomic evidence has doubled and redoubled several times over. We can now compare the exact sequence of nucleotides in every single gene in the entire genomes of individual people, apes, and even some of our extinct cousins who lived 50,000 years or more ago, and do this down to differences in single nucleotides (i.e., to identify single character differences between two texts that are about 3 billions of characters long - about 1.5 million pages of text). Comparing the genomes of these ancient deceased relatives tells us a lot about what happened as long as half a million years or more in the past.
From these kinds of evidence we now know a great deal more about our genealogical relationships than we did five years ago.
