Living things reproduce. All organisms reproduce, which means that they produce new similar organisms. Most plants and animals engage in sexual reproduction. In sexual reproduction, cells from two parents unite to form the first cell of a new organism. Other organisms reproduce through asexual reproduction, in which a single organism produces offspring identical to itself.
Beautiful blossoms are part of the apple tree's cycle of sexual reproduction.
Living things maintain a stable internal environment. All organisms need to keep their internal environment relatively stable, even when external conditions change dramatically. This condition is called homeostasis.
These specialized cells help leaves regulate gases that enter and leave the plant. SEM 1200X
Living things obtain and use material and energy. All organisms must take in materials and energy to grow, develop, and reproduce. The combination of chemical reactions through which an organism builds up or breaks down materials is called metabolism.
Various metabolic reactions occur in leaves.
Living things are made up of cells. Organisms are composed of one or more cells—the smallest units considered fully alive. Cells can grow, respond to their surroundings, and reproduce. Despite their small size, cells are complex and highly organized.
A single branch of an apple tree contains millions of cells. LM 250X
Taken as a group, living things evolve. Over generations, groups of organisms evolve, or change over time. Evolutionary change links all forms of life to a common origin more than 3.5 billion years ago. Evidence of this shared history is found in all aspects of living and fossil organisms, from physical features to structures of proteins to sequences of information in DNA.
Signs of one of the first land plants, Cooksonia, are preserved in rock over 400 million years old.