Characteristics of Life

• Nucleus - contains genetic material (DNA)
• Respiration

  Chemical reactions that break down nutrient molecules in living cells to release energy for metabolism
• Scientific names are needed for precise identification and communication among scientists
• Classification of living organisms

  Living organisms are classified based on the features that they share
• All characteristics of living organisms need to be considered when differentiating living things from non-living things
• Species


  A group of organisms that can reproduce to produce fertile offspring
• Living organisms


  Organisms that exhibit movement, respiration, sensitivity, growth and development, reproduction, excretion, and nutrition
• Reproduction


  Processes that make more of the same kind of organism (new individuals)
• Movement


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


  The taking in of materials for energy, growth, and development
• Other methods to classify organisms

  Not provided
• How to name an organism?

  1. Binomial system of nomenclature introduced by Carolus Linnaeus

  2. Worldwide convention among scientists

  3. Binomial system gives every organism a two-part name

  4. Example: Panthera leo
• Growth and development

  1. Growth is a permanent increase in size and dry mass

  2. Development makes an organism become more complex and change in form
• Characteristics of living organisms (MRS. GREN)

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


  Removal from organisms of waste products of metabolism and substances in excess of requirements
• Classification keys


  Help to place organisms into groups by asking questions about their characteristics based on morphology and anatomy that are easily observed and measured
• Linnaeus’s system of classification

  1. Provides information on evolutionary relationships among organisms

  2. Similar characteristics suggest that organisms descended from the same ancestor
• Sensitivity


  The ability to detect or respond to changes (stimuli) in the internal or external environment
• There are millions of species of organisms on Earth
• Animals are divided into two groups based on the presence of a backbone

  • Vertebrates
  • Invertebrates
• Dichotomous key


  • With only two answers to each question
• Arthropods


  • Segmented bodies
  • Jointed limbs
  • Exoskeleton
• Ferns


  • Spore-producing plants
  • Have roots, stems, leaves
  • Reproduce by spores
• Insects


  • Examples: housefly, mosquito
  • Antennae
  • Compound eyes
• Closely related organisms or organisms that share a more recent ancestor have very similar base sequences in DNA
• Viruses do not show typical features of living things unless they are inside the cells of another living organism
• Myriapods


  • Examples: centipede, millipede
• Flowering plants/Angiosperms

  • Have roots, stems, leaves
  • Produce flowers and seeds
  • Reproduce by seeds
• Five Kingdoms


  • Prokaryote
  • Protoctista
  • Fungi
  • Animalia
  • Plantae
• Sequences of bases in DNA help in classification
• Classification key

  Series of questions about the characteristics of organisms
• Vertebrates

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


  • Two cotyledons in seed
• Characteristics used to classify new species

  • Protein structure
  • Chromosome number
  • Base sequence of DNA
• Monocotyledons


  • Single cotyledon in seed
• Human and chimpanzees


  • Share 98.6% similarities
• Living organisms are grouped into five kingdoms using keys based on obvious characteristics of morphology and anatomy
• Arachnids


  • Examples: spider, scorpions, ticks
  • Spinnerets
• Crustacea


  • Example: crab, prawn, lobster
  • Gills
  • Two pairs of antennae
• reproduction is the process by which new individuals are produced from existing ones