1. Characteristics & Classification of Living Organisms

• Movement


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


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


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


  A 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


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


  The taking in of materials for energy, growth and development; plants require light, carbon dioxide, water and ions; animals need organic compounds, ions and usually need water
• • A species is defined as a group of organisms that can reproduce to produce fertile offspring
• • He named organisms in Latin using the binomial system where the scientific name of an organism is made up of two parts starting with the genus (always given a capital letter) and followed by the species (starting with a lower case letter)
• • When typed binomial names are always in italics (which indicates they are Latin) e.g. Homo sapiens
• • The sequence of classification is: Kingdom, Phylum, Class, Order, Family, Genus, Species
• The order of classification can be remembered by using a mnemonic like:

  KING PHILIP CAME OVER FOR GOOD SOUP
• Keys


  Used to identify organisms based on a series of questions about their features
• Dichotomous


  Branching into two, leads the user through to the name of the organism by giving two descriptions at a time and asking them to choose
• Using a dichotomous key


  1. Pick a single organism to start with

  2. Follow the statements from the beginning

  3. Answer each statement or question using the information provided

  4. Eventually there will be no more statements or questions left and you will have the name of the organism

  5. Pick another organism and start at the beginning of the key again, repeating until all organisms are named
• Classification systems aim to reflect evolutionary relationships between species
• Using the physical features of species (such as colour/shape/size) has many limitations and can often lead to the wrong classification of species
• Organisms share features because they originally descend from a common ancestor
• Features shared by all mammals

  • Bodies covered in hair
  • Feed young from mammary glands
  • Have external ears (pinnas)
• Morphology


  The overall form and shape of the organism, e.g. whether it had wings or legs
• Anatomy


  The detailed body structure as determined by dissection
• Originally, organisms were classified using morphology and anatomy
• As technology advanced, microscopes, knowledge of biochemistry and eventually DNA sequencing allowed us to classify organisms using a more scientific approach
• Studies of DNA sequences of different species show that the more similar the base sequences in the DNA of two species, the more closely related those two species are (and the more recent in time their common ancestor is)
• The base sequences in a mammal's DNA are more closely related to all other mammals than to any other vertebrate groups
• A is T, T is A
• C is G, G is C
• Five kingdoms of living things

  • Animals
  • Plants
  • Fungi
  • Protoctists
  • Prokaryotes
• Animals

  • Multicellular
  • Cells contain nucleus but no cell walls or chloroplasts
  • Feed on organic substances made by other living things
• Plants

  • Multicellular
  • Cells contain nucleus, chloroplasts and cellulose cell walls
  • Feed by photosynthesis
• Animal Kingdom


  Organisms are placed into groups based on several main features
• Vertebrates


  • All vertebrates have a backbone
  • There are 5 classes of vertebrates
• Invertebrates


  • Do not possess a backbone
  • One of the morphological characteristics used to classify them is whether they have legs or not
• Invertebrates with jointed legs

  • Part of the phylum Arthropods
  • Classified further into the following classes
• Animal cell

  
• Plant cell

  
• Vertebrate Table

  
• Classification of animals

  
• Arthropod class table

  
• Classification of arthropod