10.4 Interpretatiom of the human fossil record

 Why is the human fossil record considered highly incomplete?

Due to habitat factors (living on land makes fossil preservation unclear), behavioral traits (we deliberately manipulate and bury our dead), and temporal limits (we simply haven't been around for long).

What do new discoveries from comparing genomic sequences between hominin ancestors suggest?

They suggest that modern humans actively interbred with both Denisovans and Homo neanderthalensis.

What impact does each new hominin discovery have on scientific models?

Each discovery actively tests our current accepted hypotheses, allowing for clarification and better understanding, though our evidence currently remains very incomplete and overlaps.

How do scientists view changing classifications of hominins?

Classifications are not fixed, as new evidence has recently led some scientists to suggest that Neanderthals and Denisovans are actually subspecies of Homo sapiens.

What genomic evidence do we have regarding Homo sapiens neanderthalensis?

Nuclear genomes show clear evidence of interbreeding, showing that Northern Europeans carry 1–4% Neanderthal DNA.

What genomic evidence do we have regarding Homo sapiens denisova?

Nuclear genomes provide absolute evidence of interbreeding, showing that Papuans carry 7–8% and Indigenous Australians carry 3–5% Denisovan DNA.

What is the structural nature of the hominin evolutionary tree?

It is highly branched and remains subject to constant changes or updates upon making new fossil discoveries.

What has comparative genomic evidence definitively identified about Denisovans?

It has successfully identified the distinct existence of Denisovans as a unique Homo species.