Characteristics of Living Things

• Hierarchy of Living Things:

  • Biosphere: includes all ecosystems
  • Ecosystem: consists of biotic and abiotic factors
  • Community: group of organisms living together
  • Population: organisms of a particular species
  • Organism: a living thing
  • Organ: made up of tissue
  • Cell: the structural unit
  • Organelle: a specialized subunit within a cell
  • Tissue: made up of cells
  • Macromolecule
  • Molecule: made up of at least 2 atoms
  • Atom: central nucleus surrounded by electrons
  • Electron
• Characteristics of Life:

  • All living things are composed of cells
  • All living things reproduce, by either asexual or sexual means
  • Living organisms inherit traits from the parent organisms that created them
  • Living things require energy, usually in the form of ATP, to carry out energy-requiring activities such as metabolism and locomotion
  • All living things respond to stimuli in their environment
  • All living things maintain a state of internal balance
  • Living things adapt to their environment and evolve
• The cell is considered as the basic unit of life because it contains all the necessary components to carry out the functions of living organisms.
• Living things are made up of cells.
• A cell is the smallest unit capable of carrying on the processes of life.
• ATP stands for adenosine triphosphate and serves as an energy source for various processes in living organisms.
• There are two main types of cells: prokaryotes (bacteria) and eukaryotes (all other cells).
• Prokaryote cells do not have membrane-bound organelles like mitochondria, chloroplasts, or a nucleus.
• Metabolism refers to the sum total of chemical reactions occurring inside a living organism.
• Prokaryotic cells lack membrane-bound nuclei and have DNA located freely within the cytoplasm.