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6 days ago · Learn about the structure, function, and composition of the human body, the physical substance of the human organism. Explore the tissues, organs, systems, and biochemical constituents that make up the human anatomy and physiology.
- The Editors of Encyclopaedia Britannica
- What is the chemical composition of the human body?Chemically, the human body consists mainly of water and organic compounds—i.e., lipids, proteins, carbohydrates, and nucleic acids. The human body...
- What are the four main types of tissue in the human body?The four main types of tissue in the human body are epithelial, muscle, nerve, and connective.
- What are the nine major organ systems in the human body?The nine major organ systems in the human body are the integumentary system, the musculoskeletal system, the respiratory system, the circulatory sy...
May 9, 2024 · Homo sapiens, the species to which all modern human beings belong. Homo sapiens is one of several species grouped into the genus Homo, but it is the only one that is not extinct. See also human evolution.
- Brian Handwerk
- 550,000 to 750,000 Years Ago: The Beginning of the Homo sapiens Lineage. Genes, rather than fossils, can help us chart the migrations, movements and evolution of our own species—and those we descended from or interbred with over the ages.
- 300,000 Years Ago: Fossils Found of Oldest Homo sapiens. As the physical remains of actual ancient people, fossils tell us most about what they were like in life.
- 300,000 Years Ago: Artifacts Show a Revolution in Tools. Our ancestors used stone tools as long as 3.3 million years ago and by 1.75 million years ago they’d adopted the Acheulean culture, a suite of chunky handaxes and other cutting implements that remained in vogue for nearly 1.5 million years.
- 100,000 to 210,000 Years Ago: Fossils Show Homo sapiens Lived Outside of Africa. Many genetic analyses tracing our roots back to Africa make it clear that Homo sapiens originated on that continent.
- Walking Upright. The earliest humans climbed trees and walked on the ground. This flexibility helped them get around in diverse habitats and cope with changing climates.
- Tools & Food. Early humans butchered large animals at least 2.6 million years ago. By at least 500,000 years ago, early humans made wooden spears and used them to kill large animals.
- Bodies. As early humans spread to different environments, they evolved body shapes that helped them survive in hot and cold climates. Changing diets also led to changes in body shape.
- Brains. As early humans faced new environmental challenges and evolved bigger bodies, they evolved larger and more complex brains.
Jan 3, 2024 · Learn about the species that you and all other living human beings belong to, Homo sapiens, and how they evolved in Africa and spread worldwide. Explore their physical and behavioral characteristics, history of discovery, evolutionary tree, and unanswered questions.
