Charechteristics of living things

• Characteristics of living organisms


  • Movement
  • Respiration
  • Sensitivity
  • Growth
  • Reproduction
  • Excretion
  • Nutrition
• Movement


  An action by an organism or part of an organism causing a change of position or place
• Respiration


  The chemical reactions in cells that break down nutrient molecules and release energy for metabolism
• Sensitivity


  The ability to detect or sense stimuli in the internal or external environment and to make appropriate responses
• Growth


  Permanent increase in size and dry mass by an increase in cell number or cell size or both
• Reproduction


  The processes that make more of the same kind of organism
• Excretion


  Removal from organisms of the waste products of metabolism (chemical reactions in cells including respiration), toxic materials, and substances in excess of requirements
• Nutrition


  Taking in of materials for energy, growth and development; plants require light, carbon dioxide, water and ions; animals need organic compounds and ions and usually need water
• If even a single one of these characteristics are not present in an organism, then it is not alive
• Organisms can be classified into groups by features that they share
• Classification systems aim to classify groups of organisms in a systematic way, in order to reflect their evolutionary relationships
• Before the advance of technology and science, classification was traditionally based on morphology and anatomy
• Now, we can more accurately classify organisms by analysing their DNA (rather than look at appearance alone)
• Organisms which share similar DNA base sequences and protein amino acid sequences are more likely to be closely related
• Binomial system


  An internationally agreed system in which the scientific name of an organism is made up of two parts (Genus & Species)
• Genus


  A generic term used in the classification of living organisms or binomial nomenclature
• Species


  A group of organisms that can reproduce to produce fertile offspring
• Homo sapiens is an example where Homo represents the genus and Sapiens is the species</b>
• 5 main categories (kingdoms) of organisms


  • Animal
  • Plant
  • Fungus
  • Prokaryote
  • Protoctist
• All organisms are made of cells
• Universally shared cellular structures


  • Cytoplasm
  • Cell membrane
  • DNA
  • Ribosomes
  • Enzymes
• Further classification of animals

  • Vertebrates (with backbone)
  • Invertebrates (no backbone)
• Further classification of plants

  • Flowering plants
  • Ferns
• Dichotomous key


  A tool that allows the user to determine the identity of items in the natural world, such as trees, wildflowers, mammals, reptiles, rocks, and fish
• Using a dichotomous key

  1. Wings present

  2. Wings absent

  3. One pair of wings visible

  4. Two pairs of wings visible

  5. Three pairs of legs

  6. Two pairs of legs
• The plant cell has everything that an animal cell has, plus some added structures
• Cell membrane


  Allows or disallows certain things entering and exiting the cell
• Nucleus


  Contains genetic information (DNA)
• Cytoplasm


  Jelly-like substance in which everything else in the cell is suspended in
• Mitochondrion


  The "powerhouse" of the cell where respiration occurs
• Cell wall


  Provides structural support for plant cells
• Chloroplast


  Site of photosynthesis in plant cells
• Permanent vacuole


  Found in plant cells, whereas animal cells have small temporary ones
• Rough endoplasmic reticulum (RER)


  Tubular membranes near the nucleus which have ribosomes studded onto it
• Ribosomes


  Site of protein synthesis