Bio

• Biology is the study of living things which are often called organisms
• Seven 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
• There are millions of species of organisms on Earth
• Species


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


  Internationally agreed system where the scientific name is made up of two parts showing the genus and the species
• Genus


  Group of related species
• Dichotomous keys


  Used to identify organisms based on a series of questions about their features
• Dichotomous means branching into two
• Classification


  Putting things into groups
• The 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 using a more scientific approach
• Five kingdoms of living things

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


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


  • Multicellular, cells contain a nucleus, chloroplasts and cell walls made of cellulose, get nutrition by making their own food through photosynthesis
• Fungi


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


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


  • Often unicellular, cells have cell walls not made of cellulose and cytoplasm but no nucleus or mitochondria
• Two major groups within the animal kingdom

  • Vertebrates
  • Invertebrates
• Five classes of vertebrates

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


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


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


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


  • Have moist skin without scales, eggs are laid in water, larvae live in water and have gills, adults often live on land and have lungs
• Fish


  • Live in water, have scales on their skin, have gills and fins
• Four groups of invertebrate arthropods

  • Myriapods
  • Insects
  • Arachnids
  • Crustaceans
• Myriapods


  • Have many body segments, each with at least one pair of jointed legs
• Insects


  • Have bodies divided into three parts - head, thorax and abdomen, have three pairs of jointed legs and two pairs of wings
• Arachnids


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


  • Have more than four pairs of jointed legs, breathe through gills
• Groups within the plant kingdom

  • Ferns
  • Flowering plants
• Ferns


  • Have leaves called fronds, do not produce flowers but reproduce by spores
• Two groups of flowering plants

  • Monocotyledons
  • Dicotyledons