1. The World of Biology Section 1.2

2. Characteristics of Life  All living things are composed of cells  Some cells are specialized to perform specific functions

3. Types of Cells  Animals: muscle cells, blood cells, brain cells, skin cells

4. Plant cells  stone cells, parenchyma cells, xylem, phloem

5. Cell Organization  Cells structures are organized by their functions

6. Energy Use  All living things require energy to maintain cellular functions  energy is used during metabolism  Metabolism= the sum of all the chemical processes

7. Homeostasis (stable internal conditions)  Cells maintain their water content by taking in or releasing small amounts  A cell that takes in too much water will rupture

8. Growth  All living things grow by cellular division  Cellular division= the formation of two cells from an existing cell

9. Development  The process by which an adult organism arises  Produced by repeated cell divisions and cell differentiation

10. Reproduction  Reproduction is NOT essential to the survival of an individual  However, it is essential for the continuation of a species

11. The Living World  Biodiversity: ALL of the living organisms on Earth  Insects are the most abundant  Many more organisms haven’t been discovered yet, especially in rainforests