Biology revision

• Main features of protists


  • Most are unicellular, some multicellular, all have a nucleus, some may have cell walls and chloroplasts, get nutrition by photosynthesis or eating other living things
• Characteristics of reptiles

  • Have scaly skin, lay eggs with rubbery shells
• Similar base sequences in the DNA of two species

  Indicate how closely related those two species are and how recent their common ancestor is
• Mammals


  • Cats, Elephants
• Birds


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

  • Some may have cell walls and chloroplasts
• Birds

  • Toucan, Parrot, Flamingo
• Bacterial cell components

  • Strands of DNA, plasmids
• Plants


  • Multicellular, cells contain a nucleus, chloroplasts, and cell walls made from cellulose, get nutrition by photosynthesis
• Reptiles

  • Have scaly skin, lay eggs with rubbery shells
• Characteristics of amphibians

  • Moist skin without scales
  • Eggs laid in water
  • Larvae live in water with gills
  • Adults often live on land with lungs
• Myriapods


  • Centipedes, millipedes
• Characteristics of ferns

  • Leaves called fronds
  • Reproduce by spores on the underside of fronds
• Crustaceans


  • Crabs, lobsters
• Arachnids


  • Spiders, scorpions
• Groups of arthropods

  • Myriapods
  • Insects
  • Arachnids
  • Crustaceans
• Fish


  • All fish except for one or two types
• Insects


  • Grasshoppers, butterflies
• Amphibians


  • Frogs, toads
• Reptiles


  • Snakes, crocodiles, turtles
• Characteristics of flowering plants

  • Reproduce by means of flowers and seeds
  • Seeds produced inside the ovary
• A virus doesn't belong in any classification system as it is not considered a living thing
• Differences between monocotyledons and dicotyledons

  • Monocots have branching root system, parallel veins in leaves, petals in multiples of three
  • Dicots have taproot system, broader leaves with branching veins, petals in multiples of four or five