Living organisms

• Characteristics of living organisms

  • Eukaryotic organisms (plants, animals, fungi and protoctists)
  • Prokaryotic organisms such as bacteria
• Classification


  Putting things into groups to make it easier to study them
• Horses, dogs and mice are all mammals
• Animals that share similar features descended from a common ancestor, so classification reflects evolutionary relationships
• Methods of classifying living organisms

  • Common features and shared characteristics (anatomy and morphology)
  • DNA (studying the sequences of bases in DNA and amino acids in proteins)
• DNA is a more accurate method of classification than anatomy/morphology
• Characteristics of living organisms

  • Movement
  • Respiration
  • Sensitivity
  • Homeostasis
  • Growth
  • Reproduction
  • Excretion
  • Nutrition
• Humans are Homo sapiens
• Eukaryotes


  Living organisms that have cells with a nucleus
• Prokaryotes


  Living organisms that have cells without a nucleus
• Movement


  An action by an organism or part of an organism causing a change of position or place
• The Five Kingdoms


  • Animal
  • Plant
  • Fungi
  • Protoctists
  • Prokaryote (Bacteria)
• Respiration


  The chemical reactions in cells that break down nutrient molecules and release energy

  
• Animals


  • Eukaryotes
  • Multicellular organisms
  • Cells have nucleus
  • No cell wall or chloroplasts
  • Feed on organic substances made by other organisms
  • Most have nervous coordination
  • Store carbohydrates as glycogen
• Sensitivity


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


  • Eukaryotes
  • Multicellular organisms
  • Cells have nucleus and cell walls made of cellulose
  • Cells may contain chloroplasts and large vacuoles
  • Feed by photosynthesis
  • Carbohydrates are stored as starch or sucrose
  • Many have roots, stems and leaves
• Fungi


  • Eukaryotes
  • Can be single-celled or multicellular
  • Cells have nuclei
  • Usually organized into mycelium made from thread-like structures called hyphae
  • Have cell walls made of chitin
  • Do not have chlorophyll
  • Feed by saprophytic nutrition
  • May store carbohydrates as glycogen
• Homeostasis


  The maintenance of a constant internal environment to provide the best conditions inside cells for metabolism
• Bacteria


  • Prokaryotes
  • Single-celled organisms
  • No nucleus (DNA is free in the cytoplasm)
  • Have cell walls (not made of cellulose)
  • No mitochondria
• Growth


  A permanent increase in size and dry mass by an increase in cell number or cell size or both
• Useful bacteria


  • Lactobacillus bulgaricus (used to make yoghurt)
• Reproduction


  The processes that make more of the same kind of organism
• Protoctists


  • Eukaryotes
  • Single cell organisms
  • Usually larger than bacteria
  • Have nucleus
  • May or may not have cell wall and chloroplasts
  • Some feed by photosynthesis, others feed on organic substances made from other organisms
• Protoctists


  • Amoeba (looks more like animal cells)
  • Chorella (looks more like plant cells because it contains chloroplasts and can do photosynthesis)
• A pathogen is an organism that causes disease in another living organism
• Excretion


  Removal from organisms of the waste products of metabolism, toxic materials, and substances in excess of requirements
• Types of pathogens


  • Bacteria
  • Fungi
  • Protoctists
  • Viruses
• Nutrition


  Taking in of materials for energy, growth and development. Plants require light, carbon dioxide, water and ions. Animals need organic compounds and ions and usually need water.
• Characteristics of all living organisms

  • Show the 8 characteristics (MRS H GREN)
  • Are made up of cells which have a cell membrane, cytoplasm and DNA (genetic material)
  • Have ribosomes (for making proteins)
  • Have enzymes (which speed up chemical reactions such as respiration)
• Viruses are not considered to be living things
• Viruses


  • Genetic material (DNA or RNA)
  • Capsid
  • Protein coat (envelope)
• Read page 12 of your textbook and answer questions 1-4
• Levels of Organisation


  • Cells
  • Tissues
  • Organs
  • Organ Systems
  • Organism

  
• CELL


  The basic structural, functional and biological unit of all organisms
• TISSUE


  A group of cells with similar structures, working together to perform a shared function
• ORGAN


  A structure made up of a group of tissues, working together to perform a specific function
• ORGAN SYSTEM


  A group of organs with related functions, working together to perform body functions
• Different body systems


  • Let's try a question...
• Levels of organisation


  • Cells
  • Tissues
  • Organs
  • Organ Systems
  • Organism
• Cell


  The basic structural, functional and biological unit of all organisms