Human beings have many similarities and differences. The similarities make it possible for human beings to reproduce and to donate blood and organs to one another throughout the world. Their differences enable them to create diverse social and cultural arrangements and to solve problems in a variety of ways.
Fossil evidence is consistent with the idea that human beings evolved from earlier species.
Specialized roles of individuals within other species are genetically programmed, whereas human beings are able to invent and modify a wider range of social behavior. Human beings use technology to match or excel many of the abilities of other species. Technology has helped people with disabilities survive and live more conventional lives. Technologies having to do with food production, sanitation, and disease prevention have dramatically changed how people live and work and have resulted in rapid increases in the human population. Most of the time, by chance or design, a sperm never arrives or an egg isn't available.