1. Characteristics of Life Questions 1.What is the difference between unicellular and multicellular organisms? 2.What is the difference between sexual and asexual reproduction? 3.What are the levels of organization? 4.What is the difference between growth and development? 5.What is metabolism? What is the difference between heterotrophs and autotrophs? 6.What is the difference between external and internal stimulus? 7.Define Homeostasis and provide and example. 8.Define adaptation and provide and example.

2. We all have these in common. 8 Characteristics of Life

3. Living things share 8 characteristics: 1.Living things are made up of units called cells. a.Every organism is composed of at least one cell. 1.) single-celled or unicellular 2.) many-celled or multicellular

4. 2.Living things reproduce. There are two basic kinds of reproduction: a)Asexual—only one parent and all offspring are identical; for example, binary fission of bacteria or amoebas. b)Sexual—two cells from different parents unite to produce the first cell of a new organism.

6. 3.Displays Organization: Simple organization can be found within a single cell Complex organization can be found in organ systems Cells->Tissues->Organs->Organ system->Organism

7. 4.Living things grow and develop. a)For single-celled organisms, growth is mostly an increase in size. b)Multicellular organisms go through a process called development, where cells divide and differentiate into different kinds of cells.

9. 5.Living things obtain and use materials and energy. The combination of chemical reactions through which an organism builds up or breaks down materials as it carries out its life processes is called metabolism. Heterotrophs are consumers that obtain energy by eating other things. Examples humans, animals. Autotrophs (also called producers)—plants, most algae, and some bacteria obtain their energy directly from the sun through photosynthesis.

11. 6.Living things respond to their environment. a)Organisms detect and respond to stimuli from their environment. b)A stimulus is a signal to which an organism responds. c)External stimuli include temperature and light. d)Internal stimuli come from within, such as blood sugar level or feeling thirsty.

12. 7.Living things maintain a stable internal environment. a)Even though external environmental conditions may vary widely, most organisms must keep internal conditions, such as temperature and water content, fairly constant. b)Maintaining a stable internal environment is called homeostasis (Greek, same condition).

13. 8.Taken as a group, living things adapt and change over time (living things evolve). a)Plants have adapted to living in dry and hot deserts. b)Fossils of ancient organisms can be used to show how organisms have changed over time.