BISC 102: lecture #2

• tree of life groups

  • Bacteria
  • Archaea
  • Algae
  • Fungi
  • Plants
  • Animals
• Prokaryotes

  • Typically unicellular
  • Usually have smaller cells than Eukaryotes
  • Typically no membrane-bound organelles
  • DNA is circular and found in the cytoplasm
• Eukaryotes

  • Can be multicellular or unicellular
  • Usually have bigger cells than Eukaryotes
  • Cells have membrane-bound organelles
  • DNA is linear and found in the nucleus
• Types of Fungi

  • Mushrooms
  • Molds
  • Yeasts
  • Lichens
• Fungi

  • Cell walls with chitin
  • Food digestion outside cells
  • Ecological decomposers
  • Live on land
• Types of Animals

  • Invertebrates
  • Vertebrates
• Animals

  • Eat organic material
  • Breathe oxygen
  • Have muscles and move
  • Have neurons
• Types of Plants


  • Moss
  • Ferns
  • Conifers
  • Flowering Plants
• Plants


  • Cell walls with the carbohydrate cellulose
  • Produce own food by photosynthesis
  • Cells with chloroplasts with chlorophyll
• Algae


  • Diverse group that evolved multiple times
  • Mostly aquatic, photosynthetic, and not plants
• Other Eukaryotes


  • Amoeba (Amoeba proteus)
  • Malaria Parasite (Plasmodium)
  • Water Molds (Oomycetes)
• Life Cycle


  The stages of development an organism passes through during their life, including methods of sexual and asexual reproduction
• Amoebas


  • Some of the more famous and well-studied protists
  • Play vital ecological roles on land and in water
  • Some are pathogenic and deadly to humans
• Asexual reproduction


  Only one parent. Produces offspring genetically identical to the parent.
• Sexual reproduction


  Two individuals combine their genetics to produce genetically unique offspring.
• Types of asexual reproduction

  • Fission
  • Budding
  • Vegetative reproduction
  • Spore formation
  • Fragmentation
  • Parthenogenesis
• Fission


  One cell divides evenly into two. Found in many single-celled organisms.
• Budding


  One cell creates a smaller outgrowth (bud) that becomes a daughter cell.
• Vegetative reproduction


  New plants grow from a fragment or specialized reproductive structure.
• Spore formation


  A single-celled spore is released to grow into a new individual.
• Fragmentation


  A multicellular organism breaks into smaller pieces, creating new organisms
• Parthenogenesis


  A female produces an embryo from an unfertilized egg cell
• Diploid


  Cells have two sets of chromosomes
• Haploid


  Cells have one set of chromosomes
• Meiosis


  The number of chromosomes in cells gets divided in half
• Ploidy


  The number of sets of chromosome in a cell, denoted using 'n' or '2n'
• Animals


  • Found in nearly half of animal groups
  • Are DIPLOID and only have short-lived haploid gametes
• Animal life cycle


  1. Meiosis reduces number of chromosomes by half

  2. Diploid number of chromosomes restored in zygote
• Fungi


  • Are HAPLOID and only have a short-lived diploid zygote
  • Can reproduce asexually by producing SPORES or if filaments are broken into fragments
• Fungal sexual reproduction


  1. Two compatible strains fuse their cytoplasm, so cells have multiple nuclei (HETEROKARYOTIC)

  2. Later the nuclei fuse (SYNGAMY) to produce ZYGOTE that undergoes meiosis to produce SPORES
• Plants


  • Undergo ALTERNATION of haploid and diploid generations
  • Plant life cycles alternate between two different multicellular stages; the SPOROPHTYE is diploid, and the GAMETOPHYTE is haploid
• Plant life cycle


  1. Gametophyte produces gametes

  2. Fertilization produces zygote

  3. Zygote develops into sporophyte
• Algae


  • All types of life cycles are found among the algae
  • Asexual reproduction is really common, especially among unicellular and filamentous algae that use fission and fragmentation
  • Diploid dominant, alternation of generations, and haploid dominant life cycles are all found
• archea and bacteria

  famous for their extreme diversity of lifestyles and habitats
• invertebrates 


  animals without a spine/backbone
• vertebrates 


  animals with a bone or cartilage skeleton
• plants significance

  foundation of life on land:

  • provide food and habitat
  • medicine and material they provide
  • cultural and social relations
• algae significance 


  foundational to aquatic life, photosynthesis creates food for communities of life
• types of asexual reproduction

  • binary fission
  • budding
  • vegetative reproduction
  • spore formation
  • fragmentation
  • parthenogenesis