Biology 1307

• Biological species concept


  If two populations do not interbreed in nature (or fail to produce fertile offspring when they do) they belong to different species
• Morphological species concept


  All individuals of a species share measurable (quantitative) traits that distinguish them from individuals of other species
• Limitations of morphological species concept


  • Not always accurate - some closely related species are nearly identical in their appearance
  • Some members of the same species show a great amount of variety
  • Does not reveal evolutionary relationships
• Phylogenetic species concept


  Species are defined as a cluster of populations that emerge from a shared recent evolutionary history (they share similar genetics)
• Limitations of phylogenetic species concept


  • It is a new concept
  • Uses both morphological and genetic sequence data
• Reproductive isolation

  Prevents individuals of different species from mating and producing successful progeny
• Prezygotic isolating mechanisms


  • Ecological isolation
  • Temporal isolation
  • Behavioral isolation
  • Gametic isolation
  • Mechanical isolation
• Postzygotic isolating mechanisms


  • Hybrid inviability
  • Hybrid sterility
  • Hybrid breakdown
• Allopatric speciation


  Occurs when a species separates into two separate groups that are isolated from one another
• Sympatric speciation


  The process through which new species evolve from a single ancestral species while inhabiting the same geographic region; the species become isolated from each due to breeding preferences
• Humans are not descended from monkeys or any other primate living today however humans share a common ancestor
• Paraphyletic group


  Includes the most recent common ancestor of the group
• Monophyletic group


  Includes the most recent common ancestor of the group and all of its descendants (clade)
• Polyphyletic group


  Does not include the most recent common ancestor of all members of the group
• Plasmids


  Circular DNA molecules that are found in the cytoplasm, giving the cells a particular advantage that they would otherwise not have
• Different kinds of plasmids


  • Resistance plasmids
  • Degradative plasmids
  • Col plasmids
  • Virulence plasmids
  • Fertility plasmids
• Gram positive bacteria


  Cell wall consisting of a thick peptidoglycan layer
• Gram negative bacteria


  Cell wall consisting of a thin peptidoglycan layer
• Cyanobacteria were the first organisms to use photosynthesis; critical to the abundant accumulation of oxygen in the atmosphere
• Types of horizontal gene transfer


  • Conjugation
  • Transformation
  • Transduction
• Three branches of archaea


  • Methanogens
  • Extreme halophytes
  • Extreme thermophiles
• Six supergroups of protists


  • Excavata
  • Chromalveolata
  • Rhizara
  • Archaeplastida
  • Amoebozoa
  • Opisthokonta
• Characteristics and diversity of protists


  • Habitat
  • Structure
  • Movement
  • Metabolism
  • Reproduction
• Cytoplasmic streaming


  The cytoplasm flows through the hyphae, allowing for the transport of food to all parts of the fungus
• Types of asexual reproduction in fungi


  • Fragmentation of hyphae
  • Budding
  • Asexual Spores
• Sexual reproduction in fungi


  Takes place when genetically different mating types (+ and -) come together (fuse) resulting in the formation of a diploid (2n) zygote
• It is believed that all land plants evolved from green algae, specifically Spirogyra
• The dominant generation in bryophytes is the diploid sporophyte
• Types of asexual reproduction in fungi


  • Fragmentation of hyphae
  • Budding
  • Asexual Spores
• Fragmentation of hyphae


  Hyphae breaks away from the mycelium and grow into separate individuals
• Budding


  As in yeast
• Yeast

  Single celled fungi
• Asexual Spores

  Sporangia or conidia (dust)
• Sexual Reproduction in fungi

  Genetically different mating types (+ and -) come together (fuse) resulting in the formation of a diploid (2n) zygote
• All land plants evolved from green algae, specifically Spirogyra
• Algae

  An informal term for a large, diverse group of photosynthetic eukaryotic organisms
• Bryophytes

  Seedless, nonvascular plants
• Domains and Kingdoms of bryophytes

  • Domain Eukarya
  • Kingdom Plantae
  • Supergroup: Archaeplastida
• Alternation of Generations

  The diploid phase and haploid phase
• Gametophyte generation in bryophytes

  The dominant generation