Characteristics & Classification of Living Organism

• Mrs GREN


  Mnemonic to remember 7 characteristics of living things: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition
• 7 characteristics of living things

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


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


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


  Ability to detect and respond to changes in the internal or external environment
• Growth


  Permanent increase in size and dry mass
• Reproduction


  Processes that make more of the same kind of organism
• Excretion


  Removal of the waste products of metabolism and substances in excess of requirements
• Nutrition


  Taking in of materials for energy, growth and development
• Species


  Group of organisms that can reproduce to produce fertile offspring
• Binomial system


  Internationally agreed system for naming species, using genus and species
• Genus


  Group of related species
• Dichotomous key


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


  Putting things into groups
• Main reason for classifying living things is to make it easier to study them
• Classification systems aim to reflect evolutionary relationships between species
• Studying DNA sequences helps classify organisms more scientifically
• 5 Kingdoms


  • Animals
  • Plants
  • Fungi
  • Protists
  • Prokaryotes
• Animals


  • Multicellular, cells contain nucleus but no cell walls or chloroplasts, get nutrition by eating other living things
• Plants


  • Multicellular, cells contain nucleus, chloroplasts and cell walls made of cellulose, get nutrition through photosynthesis
• Fungi


  • Usually multicellular, cells have nuclei and cell walls not made of cellulose, feed by saprophytic or parasitic nutrition
• Protocists

  • Most are unicellular but some are multicellular, some have cell walls and chloroplasts, some make their own food, some eat other living things
• Prokaryotes


  • Often unicellular, have cell walls not made of cellulose, have cytoplasm but no nucleus or mitochondria
• Vertebrate groups


  • Mammals
  • Birds
  • Reptiles
  • Amphibians
  • Fish
• Mammals


  • Have fur or hair, young feed on milk from mammary glands, heart has 4 chambers, different types of teeth
• Birds


  • Have feathers, lay eggs with hard shells, have beak, have wings instead of 4 limbs
• Reptiles

  • Have scaly skin, lay eggs with rubbery shells
• Amphibians


  • Have moist skin without scales, eggs laid in water, larvae have gills, adults have lungs
• Fish


  • Live in water, have scales, have gills, have fins
• Invertebrate groups


  • Arthropods (Myriapods, Insects, Arachnids, Crustaceans)
  • Others
• Arthropods


  • Have jointed legs
• Myriapods

  • Body has many segments, each with at least 1 pair of jointed legs
• Insects


  • Body divided into 3 parts: head, thorax, abdomen, 3 pairs of jointed legs, 2 pairs of wings
• Arachnids


  • Have 4 pairs of jointed legs, breathe through book lungs
• Crustaceans


  • Have more than 4 pairs of jointed legs, breathe through gills
• Plant groups


  • Ferns
  • Flowering plants (Monocots, Dicots)
• Ferns


  • Have leaves called fronds, reproduce by spores
• Monocots


  • Branching root system, parallel leaf veins, flower parts in multiples of 3
• Dicots


  • Taproot system, branching leaf veins, flower parts in multiples of 4 or 5
• Viruses are not considered living things as they cannot carry out life processes on their own