Characteristics of Living Things All living things are composed of one or more cells. A cell is the structural and functional unit of life. All cells are surrounded by a cell membrane, which separates the contents of the cell from the cell’s environment

These Are All Single Cell Organisms

Environmental Changes All living things are able to sense changes in their environment and to respond to that change. When you are physically active your body heats up. To prevent overheating your body begins to sweat which acts as a coolant on your skin. Stimulus (plural = stimuli): a change that affects the activity of an organism. What changes are visible in the habitat of these Polar Bears? How does this change affect hunting for food? Survival?

Homeostasis: the maintenance of a stable internal environment. The body is always striving to maintain a balance. Homeostasis Homeostasis is the maintenance of a "steady state", a state of chemical and physical consistency in the face of changes in the surroundings. Maintenance of such a steady state requires a sensitivity and appropriate response to even small changes. This rabbit loses body heat through its oversized ears.

Stimulus: Hot pan Response: Remove hand Responding to External Changes

Reproduction The single-celled amoeba demonstrates a simple method of asexual reproduction. It divides in half by a process called fission, producing two smaller daughter cells. After a period of feeding and growth, these two daughter cells will themselves divide in half. Living things reproduce in one of two ways: 1.Sexual reproduction: two parents produce offspring that share characteristics of both parents. Most plants and animals reproduce sexually. 2.Asexual reproduction: a single parent produces offspring that are identical to the parent. Most single-celled organisms and many multicellular organisms reproduce asexually.

DNA and Metabolism The cells of all living things contain the molecule deoxyribonucleic acid or DNA. DNA carries the instructions for the organism's traits. When organisms reproduce they pass copies of their DNA to their offspring. The passing of these traits is called heredity. Metabolism: the sum of all the activities that the organism performs. This includes the use of energy to carry out the chemical activities of life.

Living Things through cell division in life stages structural unit functional unit Cells Grow and develop internally (homeostasis) externallySense and respond to change Reproduce sexually asexually DNA Use Energy for chemical processes Controls heredity