BIO PREFINAL(2)

• Phylogenetic Tree is how an organism is named and classified should reflect its place within the evolutionary tree of life.
• Systematics, which includes taxonomy, is a discipline of biology that

  focuses on classifying organisms and determining their evolutionary

  relationships.
• The evolutionary history of a species or group of species is called

  phylogeny
• The Greek word phylon means tribe
• The Greek word genesis means origin
• In a Phylogenetic Tree, the point where a split occurs, called a branch point, represents where a single lineage evolved into a distinct new one
• In a Phylogenetic Tree, a lineage that evolved early from the root and remains unbranched is called basal taxon
• In a Phylogenetic Tree, when two lineages stem from the same branch point, they are called sister taxa
• In a Phylogenetic Tree, a branch with more than two

  lineages is called a polytomy
• Cladistics is a one relatively new system of phylogenetic classification
• A derived character is a feature that apparently evolved only

  within the group under consideration
• Taxonomy literally means “ arrangement law ”
• Taxonomy is a branch of biology concerned with identifying, naming,

  and classifying species.
• The taxonomic classification system (Linnaean System) is invented by the Swedish botanist Carl Linnaeus
• The taxonomic classification system, also know as Linnaean System is

  invented by the Swedish botanist Carl Linnaeus
• In the Binomial naming, the first part of the binomial consists of the genus to which the species belong
• Bacteria and Archaea are the two main branches of prokaryotic evolution
• cocci is the spherical cells
• Streptococci is the cocci in chains
• Staphylococci is the cocci in clusters
• bacilli is the rod shaped prokaryotes
• Bacterial cell walls contain peptidoglycan composed of polysaccharide

  chains that are cross-linked by unusual peptides
• Bacteria are divided into two major groups: gram positive and

  gram negative
• in gram-positive bacteria, the wall is thick
• In gram-negative bacteria, the wall is thin
• In gram-negative bacteria, the cell wall is surrounded by an outer membrane that contains lipopolysaccharides and lipoproteins.
• In medicine, Gram stains are often used to detect the presence of bacteria and indicate the type of antibiotic to prescribe.
• Capsule is found outside the cell wall of a bacteria
• The capsule found in some species enables the organism to attach to

  surfaces, protects it from dehydration and attack by phagocytic cells, and increases its resistance to our immune responses
• Some prokaryotes have flagella (singular, flagellum) used for

  locomotion
• Fimbriae is the hairlike projections that enable some prokaryotes to stick to a surface or to one another - attachment
• Photoautotrophs are prokaryotic cells do not have chloroplasts, but some prokaryotes have thylakoid membranes where photosynthesis takes place
• Photoheterotrophs obtain energy from sunlight but get

  their carbon atoms from organic sources
• Chemoautotrophs don’t depend on sunlight, they can thrive in conditions that seem totally inhospitable to life (ex. Hydrothermal vents)
• Chemoheterotrophs is by far the largest and most diverse group of prokaryotes. Almost any organic molecule is food for them.
• Reproduction in prokaryotes is asexual and usually takes place by

  binary fission.
• In transformation, the prokaryote takes in DNA found in its environment

  that is shed by other prokaryotes, alive or dead
• In transduction, bacteriophages sometimes also move short pieces of

  chromosomal DNA from one bacterium to another. It results in a recombinant organism.
• In conjugation, DNA is transferred from one prokaryote to another by means of a pilus, which brings the organisms into contact with one another. The DNA transferred can be in the form of a plasmid or as a hybrid, containing both plasmid and chromosomal DNA.
• Members of the domain Archaea are abundant in many habitats,

  including places where few other organisms can survive.