Its Alive – or is it?

1. Its Alive – or is it? The Characteristics of Life

2. I can… • Describe the biological criteria that need to be met in order for an organism to be considered alive

3. 6 Characteristics of Life • In order for ANY organism, no matter how large or small, to be considered alive, it must exhibit the following 5 characteristics: • Organization • Ability to acquire materials and energy • Ability to maintain homeostasis • Ability to respond • Ability to reproduce and grow • Acquire adaptations

4. Organization within a living organism… • Organization of living things begins with atoms, which make up basic building blocks called elements and molecules • The cell is made up of molecules and is the basic structural and functional unit of all living things • Different cells combine to make up tissues • Tissues combine to make up an organ • Specific organs work together as an organ system • Multicellular organisms contain organ systems • Each level of organization is more complex that the level preceding

5. Working with what we have learned… • Make flow chart of the levels of organization – within an organism • At each level, give at least 2 examples

6. Organization between living organisms… • A species is the same type of organism • A population is group of the same species in a particular area • Interacting populations in a particular area is a community • A community PLUS its physical (non-living) environment is an ecosystem • The biosphere is comprised of regions of the Earth’s crust, waters and atmosphere inhabited by organisms

7. Working with what we have learned… • Using our classroom as our “particular area”, give examples for each level of organization found between organisms

8. Acquire Materials and Energy • Maintaining organization and conducting life-sustaining processes require an outside source of energy • The ultimate source of energy for nearly all live on earth is the sum • Plants and certain other organisms convert solar energy into chemical energy by the process of photosynthesis • Metabolism is all the chemical reactions that occur in the cell

9. Ability to maintain homeostasis… • All organisms must maintain a state of biological balance, or homeostasis • Temperature, moisture level, pH level, etc.. Must be maintained within the tolerance range of the organism • Organisms have intricate feedback and control mechanisms to maintain homeostatic balance

10. Ability to Respond… • Living things interact with the environment and with other living things and need to respond accordingly • Response often results in movement of the organism • A plant bending toward the sun to capture solar energy or a turtle withdrawing into its shell for safety • Responses help ensure survival of the organism and allow the organism to carry out biological activities • The collective responses of an organism constitute the behavior of the organism

11. Ability to reproduce and grow… • Reproduction is the ability of every type of organism to give rise to another organism like itself • Bacteria, protozoans, and other unicellular organisms simply split in two (binary fission) – asexual reproduction • Multicellular organism often unite sperm and egg, each from a different individual, resulting in an immature individual which develops into the adult – sexual reproduction • The instructions for an organism’s organization and development are encoded in genes • Genes are comprised of long molecules of DNA (Deoxyribonucleic acid) • DNA is the genetic code for all living things

12. Acquire to Adaptations… • Adaptations are modifications that make organisms suited to their way of life • Occur over a long period of time