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

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

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

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

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

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

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

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

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

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

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

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