Lecture 1

• Two levels of Diversity

  1. Intraspecific Variation: variation among individuals w/in species 2. Interspecific Variation: variation among millions of species
• Huge differences between species but also fundamental commonalities

  Similarities: DNA code, sequence similarity, biochemistry
• what is responsible for commonalities and differences among species?

  Evolutionary history: decent with modification from shared common ancestors
• Difference between similar and dissimilar species in terms of ancestors?

  Similar species have more recent common ancestors(humans and chimps) compared to dissimilar species(humans and butterflies).
• How is knowledge on Biological Diversity organized?

  a hierarchical system based on these evolutionary lineages (like a family tree)
• What is phylogeny?

  The evolutionary history of a species or group of related species
• what is systematics? 


  discipline of classifying organisms and determining their evolutionary relationship
• homology 


  similarity due to ancestry (the more complex two similar structures are the more likely it is that they are homologous)
• analogy 


  similarity due to convergent evolution
• Convergent evolution


  when similar environmental pressures and natural selection produce similar adaptations in organisms from different evolutionary lineages
• shared ancestral character

  character originated in ancestor of the taxon
• shared derived character


  evolutionary novelty unique to particular clade (character can be both ancestral and derived)
• five kingdoms

  monera(prok), protista, plantae, fungi, and animalia
• more recent: 3 domain system

  Bacteria, archea, eukarya
• Horizontal gene transfer and how does it occur?

  the movement of genes from one genome to another

  occurs by exchange of transposable elements and plasmids, viral infection
• Unicellular prokaryotes domains:

  bacteria and archaea
• prokaryotic cells shapes

  Spheres(cocci), rods(bacilli), spirals(also like long worm)
• Difference of bacteria and archaea?

  bacteria cell walls(made of cellulose or chitin) contain peptidoglycan while archaea lack them and still contain polypeptides
• what is peptidoglycan?

  network of sugar polymers cross-linked by polypeptides
• Do prokaryotes have organelles and nuclei?

  no they don't have any nuclei
• what are frimbriae? 


  hairlike appendages that help cells adhere to other cells or substrate

  sex pilus are like longer frimbriae
• what three factors that contribute to genetic diversity?

  1. rapid reproduction
  2. mutation
  3. genetic recombination
• how is prok DNA from diff individuals brought together?

  transformation, transduction, and conjugation
• transformation:

  prok cell can take up and incorporate foreign DNA from the surrounding environment
• conjugation:

  when plasmids(small pieces of DNA rings) are transferred between two bacterial cells that are temp joined
• transduction:


  movement of genes between bacteria by bacteriophages
• Photoautotroph need what ?


  light and CO2
• chemoautotroph need what?

  inorganic chemicals and CO2
• Photoheterotroph need what?

  light and organic compounds
• chemoheterotroph need what?

  Organic compounds
• what are exotoxins?


  cause disease even if the prok that produce them are not present / secreted by the organism
• what are endotoxins? 


  released when bacteria die and their cell wall break down
• roles of prokaryotes in biosphere?

  they recycle chemical elements in ecosytem and chemoheterotrophic proks function as decomposers and are nitrogen fixing
• clade excavata


  characterized by whip like flagellum with "flagellates" some specialized organelles: 'eyespots'
• Clade Chromalyeolata 


  locomotion is cilia

  free swimming ciliates, in attached spcies cilia move water past and in other cilia help them crawl
• clade chromalveolata


  parasites and includes diatoms, ciliates, dinoflagellates
• clade rhizaria


  includes types of amoebas, radiolarians, most have shells made of silica and use filamentous pseudopods
• development stages: 


  cleavage: sequence of cell divistions zygote divides (mitotic process)

  blastula
• Diploblastic org?


  two germ layers (cnidaria and ctenophora)

  ectoderm(outside) and endoderm(inner most layer lines the gut)
• Triploblastic org:

  three germ layers:

  ectoderm: surrounds blastocele, outer layer

  mesoderm: between ectoderm and endoderm, supportive contractile

  endoderm:surrounds inner body cavity