LIFESCI 1 Chapter Notes - Chapter 1: Cell Theory, Smallest Organisms, Cell Membrane
Document Summary
Chapter 1: biology and the tree of life. Two of the greatest unifying ideas in biology: the cell theory and the theory of evolution by. Natural selection (which leads to the tree of life) Although there is no simple definition of life endorsed by all biologists, most agree that organisms share a suite of five different characteristics. Energy: to stay alive and reproduce, organisms have to acquire and use energy. To give just two examples: plants absorb sunlight, animals ingest food. Cells: organisms are made up of membrane-bound units called cells. A cell"s membrane regulates the passage between interior and exterior spaces. Information: organisms process hereditary, or genetic, information encoded in units called genes. Replication: one of the great biologists of the 20th century, francois jacob, said that the dream of a bacterium is to become two bacteria . Almost everything an organism does contributes to one goal: replicating itself.
