Key Concepts

Humans, like all species, are a product of evolution. The Spitzer Hall of Human Origins presents key and cutting-edge evidence—fossils, genetic data, and artifacts—that scientists use to assemble the evolutionary story of our taxonomic family, the hominids. Here are the exhibition's key educational concepts:

Neanderthal skull cap
(click to enlarge)
©AMNH

Modern human DNA in a test tube.
(click to enlarge)
©AMNH

Ample scientific evidence documents human evolutionary history.

Fossil Evidence: Scientists have long used fossils to reconstruct the history of hominids and our larger taxonomic group, the order Primates. The fossil record shows that hominids have a past that is long (about 7 million years) and diverse (comprising at least 20 species). New finds continue to clarify what other hominids looked like, and how and when they lived.

Genetic Evidence: Technology to study DNA has emerged in the past few decades, adding to what fossils tell us. Because DNA is passed from generation to generation and can change over time, it can document changes in species and populations: Tracking heredity geographically explains how modern humans migrated around the Earth. Comparing differences between species' DNA gives measurements of relatedness. By studying how genes control body structure and function, scientists can explore behavior.

Several mechanisms drive evolution.
Except for identical twins, no two individuals share the exact same set of genes and physical features. Because of genetic variation, and the fact that some individuals survive to pass traits to future generations, populations of organisms evolve. The evolution of new species involves several processes:

Mutation: Variation can arise from random changes, or mutations, in the DNA an individual has inherited. Mutations may or may not impact the ability to survive and reproduce.
Natural Selection: An individual with heritable features that enable it to cope better with its environment tends to pass them to the next generation. Over time, a population of individuals will exhibit more of the better-adapted features.
Genetic Drift: In small populations, genes and traits will increase in abundance over generations by chance, not because they impact an individual's chance of survival.

Evolutionary trees represent the history of life.
Evolution does not progress toward a goal. It also does not proceed as a single line of sequential species. Rather, new species diverge from common ancestors like branches on a tree. Trees of life depict relatedness between species, living and extinct. Evolutionary trees show how specific taxonomic groups evolved over time. The hominid evolutionary tree tells us that at many times in the past several hominid species lived on Earth simultaneously. Some survived much longer than the 150,000 years Homo sapiens has existed. Yet all hominids went extinct—except our species.

Human populations migrated to many environments and diversified.
Early humans emerged in Africa, then spread in waves throughout that continent and the rest of the world. As populations occupied different environments, modern humans continued to change. This is evident in the diversity of features seen across individuals and populations. (See the sidebar "Evolution and Human Diversity.")

The human brain is unique.

Humans have large brains relative to body size, but it isn't the size that sets us apart. Humans are capable of symbolic thought: We frame the world in abstract, creative terms. Homo sapiens' mental complexity may be what led our species to out-compete all other hominids.

Only modern humans create complex culture.
Our mental capacities enable us to produce increasingly complex tools and a vast range of symbolic expression, such as art, language, and music. Both innate talent as well as skills nurtured in society create the cultural complexity of humans. Our diversity of cultures is a hallmark of our humanity.

Sackler Educational Laboratory for Comparative Genomics and Human Origins
This unique resource for hands-on study of genetics and human evolution highlights the work of the Museum's Sackler Institute for Comparative Genomics. More information...