 All living things are made up of one (unicellular) or more cells (multicellular). › Cell - smallest unit capable of performing all life’s processes.

 Living organisms have organization. › Organization - high degree of order within an organism’s internal and external parts and its interaction with the living world.  Highest level of organization- organism is made up of organ systems that carry out specific functions within the organism (Ex: digestive system).

 Living things respond to a stimulus. › Stimulus - physical or chemical changes in an organism’s internal or external environment. › This is essential to survival.

 Homeostasis - maintenance of a stable internal environment despite the constant changing of an organisms external environment.  Organisms have built in system that maintains stable internal conditions, such as: › Temperature › Water content › Nutrient uptake by cell

 Energy is required to power ALL life’s processes, such as › Growth and development › Movement › Repair  Metabolism - sum of all the chemical reactions that take in and transform energy and materials from the environment.

 Photosynthesis › Plants, algae, phytoplankton, and some bacteria capture and use the sun’s energy to make sugar molecules.  Organisms that cannot make their own food must get their food from other organisms.

 Nonliving things (Ex: icicles) grow by accumulating more of the same material (Ex: ice) of which they are made.  LIVING things grow through division and enlargement of cells. › Living multicellular organisms mature through cell division, cell enlargement, and development.

 Development - process by which organisms become more adult. › Involves: cell division, cell differentiation, or specialization. › Your body contains trillions of specialized cells (Ex: nerve cells, blood cells, skin cells..), all of which originated from a single cell, the fertilized egg.

 Reproduction - Organisms produce more organisms like themselves. › NOT needed for individual’s survival. However, reproduction is ESSENTIAL to survival of a species.  Hereditary information is passed from parent to offspring through DNA. Short segments of DNA make up individual genes.

 Two major types of reproduction: › Sexual reproduction- hereditary information recombines from TWO organisms. Offspring are similar but not identical to either parent.  Ex: Frogs › Asexual reproduction- herditary information comes from a single parent organism. Offspring are identical to parent.  Ex: bacteria

 The basic GENETIC characteristics of an individual organism do not change over their lifetime.  Populations of organisms DO change through time, or evolve. › This is critical to survival in a changing world. › Explains the diversity of life-forms we see on Earth today.

 Living things come in many varieties (huge diversity ).

 Although diverse, living things are characterized by unity, or things they have in common. › Genetic code- rules governing how cells use hereditary information. › Organelles that carry out life’s functions.

 “Tree of Life”- a model of the relationships by ancestry among organisms. › Living things share certain genes, yet no two types of organisms share all the same genes. › Three main lineages, called domains. Organisms found on closer branches (lineages) have more similar sets of genes. 1.Bacteria 2.Archaea 3.Eukarya - complex cells containing a nucleus. Less complex cells

 Another system of grouping organisms divides life into six categories called kingdoms. › 4 kingdoms within domain Eukarya  Kingdoms Animalia, plantae, fungi, protista › 1 kingdom within domain Archaea  Kingdom Archaea › 1 kindom within domain Bacteria  Kingdom Bacteria

 Ecology - study of how organisms interact with each other and the environment. › Study single species as well as ecosystems.  Ecosystems - communities of species and their physical environment.  Studies have shown that species depend on each other and their physical environment for survival.

 Evolution - (decent with modification) process in which inherited characteristics within POPULATIONS change over generations. › Can lead to genetically distinct populations and development of new species.

 Theory of Evolution by Natural Selection › Natural Selection - organisms with certain favorable traits survive and reproduce more than those without them.  Those traits that increase an organism’s ability to survive and reproduce are called adaptations.