Studying Life 1-3

Biology Means study of life Science that seeks to understand the living world In order to be considered alive, organisms must meet 8 criteria

1. Made up of cells Cells - smallest unit of life Unicellular - made of 1 cell Multicellular - made of several cells

2. Reproduction Produce new organisms through a process called reproduction Asexual - single parent, divides in 2, creates identical offspring Sexual - 2 parents, genetically different offspring

3. Based on a Genetic Code Offspring inherit traits from parents Directions for inheritance carried in DNA - genetic code

4. Growth and Development All living things grow during at least part of their lives Some, like bacteria, just grow in size Multicellular organisms go through stages of development

5. Need for Material & Energy Organisms need materials and energy to grow, develop, and reproduce Get energy from photosynthesis or consuming energy stored from photosynthesis Metabolism

6. Response to Environment Organisms detect and respond to stimuli from environment External stimuli - light & temp. Internal stimuli - blood sugar level

7. Maintaining Internal Balance Organisms must keep internal temp. and water content fairly constant to survive Homeostasis - maintaining internal balance –Shiver, sweat

8. Evolution As a group, organisms evolve, or change over time Ex. - fish bony plates to scales

Levels of Organization Biosphere Ecosystem Community Population Organism Groups of cells Cells Molecules