Characteristics of Life


  1. Characteristics of Life - All living things share these characteristics: they are made up of one or more cells, reproduce, move, acquire and use energy, grow and develop, have levels of organization, contain genetic information, respond to their environment, and adapt and evolve.

  2. Cell Theory - States that living things are made up of one or more cells, all cells come from pre-existing cells, and the cell is the basic unit of life.

  3. Unicellular - Made up of one cell.

  4. Multicellular - Made up of more than one cell.

  5. Eukaryotic Cells - Cells that contain a membrane-bound true nucleus and other membrane-bound organelles.

  6. Prokaryotic Cells - Cells that have DNA which is NOT surrounded by a membrane and which have no membrane-bound organelles.

  7. Reproduction - The main purpose is to produce offspring, which ensures genetic continuity from generation to generation.

  8. Sexual Reproduction - The type involving sperm and egg gametes.

  9. Gametes - Sperm and egg.

  10. Asexual Reproduction - The type NOT involving sperm and egg.

  11. Locomotion - Movement exhibited by organisms that are free moving and can move on their own.

  12. Tropic Growth Movements - Directional growth responses to stimuli.

  13. Nastic Growth Movements - Non-directional growth responses to stimuli.

  14. Growth Movements - Movements exhibited by organisms that are NOT free moving.

  15. Autotrophs - Organisms that can MAKE their own glucose using a green pigment called chlorophyll in a process called photosynthesis.

  16. Photosynthesis - A process in which organisms make their own glucose using chlorophyll, along with the energy found in sunlight.

  17. Chlorophyll - A green pigment used to make glucose.

  18. Sunlight - Energy used in photosynthesis.

  19. Heterotrophs - Organisms that CANNOT make their own glucose. They must consume other organisms for energy.

  20. Acquiring Energy - Can be done in two major ways: some organisms are autotrophs and some organisms are heterotrophs.

  21. Using Energy - Done through chemical reactions within the cells of an organism.

  22. Metabolism - The sum of these chemical reactions.

  23. Anabolism - The BUILDING UP of large and complex molecules from small and simple ones.

  24. Catabolism - The BREAK DOWN of large and complex molecules into small and simple ones.

  25. Small and Simple Molecules - Molecules used to build large and complex molecules.

  26. Large and Complex Molecules - Molecules that can be broken down into small and simple ones.

  27. Growth and Development in Unicellular Organisms - A unicellular organism must increase the volume of its cytoplasm, which involves gaining more cytosol and organelles.

  28. Cytosol - The liquid of the cell.

  29. Organelles - The machinery of the cell.

  30. Growth and Development in Multicellular Organisms - A multicellular organism must undergo cell division and specialization.

  31. Cell Specialization - Cells specialize into different types of tissues.

  32. Levels of Organization - Atom → molecule → macromolecule → organelle → cell → tissues → organ → organ system → organism.

  33. Genetic Information - Comes in the form of a molecule called DNA.

  34. DNA - Stands for deoxyribonucleic acid.

  35. RNA - Genetic information found in viruses, including retroviruses.

  36. Viruses - Do not exhibit some of the other characteristics of life and are therefore classified as non-living.

  37. Stimuli - Changes in the environment that living things respond to.

  38. Internal Environment - The environment inside the organism.

  39. External Environment - The environment outside the organism.

  40. Response to Change - Brings the organism back to equilibrium or homeostasis.

  41. Homeostasis - A constant internal state.

  42. Charles Darwin - The British naturalist who came up with a mechanism for evolution.

  43. Evolution - A mechanism explained by Charles Darwin through natural selection.

  44. Natural Selection - The mechanism for evolution proposed by Charles Darwin.

  45. Mutations - Random changes in DNA that cause individuals to differ in genetically determined traits.

  46. Adaptations - Traits that allow organisms to SURVIVE and REPRODUCE better than others.

  47. Fitness - Individuals with traits or adaptations that allow them to SURVIVE and REPRODUCE better than others are said to have more fitness.