Exam 2 Phylogeny and Systematics 02 06 2013 5 Kingdom classification system in use through the late 1900s Monera Protista unicellular eukaryotes Plantae photosynthesis multicellular eukaryote Fungi feed by absorption eukaryote most are multicellular Animalia eukaryote multicellular feed by ingestion Place according to similar homologous structures o Outdated no longer used used through 1900s o Now it s the three domains eukaryotes bacteria archaea o Prokaryotes are different from Protista Three Domain System Dr Woese by sequencing certain segments of all species DNA o DNA RNA rRNA proteins o Bacteria and Archaea used to both be in Monera which was very wrong they are different o Within the three domains are multiple kingdoms Bacterial kingdoms Bacteria Archaean kingdoms Archaea Protistan kingdoms Plantae Fungi Animalia Eukarya Bacteria Archaea DNA RNA sequence more similar to Eukarya than Bacteria Eukarya Classifications Taxon taxa the named taxonomic units at any level in this taxonomic hierarchy Most inclusive domain Least inclusive species homo sapien Did King Philip Come Over For Gumbo Sunday Domain Eucarya o Kingdom Animalia Phylum Chordata Class Mammalia Order Carnivora o Family Felidae Genus Panthera Species Panthera pardus Panthera genus Pardus specific epithet that refers to one species in the genus Panthera Linnaeus convinced us to use a hierarchical classification system Darwin provided us with the mechanism by which evolution results in descent with modification These two bring us to phylogenetics reconstructing the evolutionary relationships among organisms Macroevolution and Phylogeny Phylogenic tree hypothesized genealogy traced back to the last common ancestor the most recent through hierarchical dichotomous branching Cladistics the principles that guide the production of phylogenic trees cladograms Able to date species in two ways o 1 Radiometric dating of fossils more accurate o 2 Observation of differing nucleotides in strands of DNA of different species with common ancestors Node branch point speciation event Lineage clade an entire branch A clade is a monoplyletic group an ancestral species and all its A paraplyletic group consists of an ancestor and some of its A polyphyletic group lacks the common ancestor of species in the The fossil record is especially valuable and the only option for many Cladistic principles allow us to construct hypothesized phylogenetic descendants descendants group trees extinct taxa Cladistic Analysis Fossils provide morphological data for extinct species whereas comparisons of multiple types of traits including molecular do so for extant species Similar characters morphological behavioral molecular etc traits or features suggest relatedness But not all similarity derives from common ancestry Convergent evolution can produce superficially similar traits that lack homology As a general rule the more homologous characters shared by two species the more closely related they are Sequences of DNA and RNA nucleotides and proteins amino acids and used as characters as a general rule the more recently what two species were same species the more closely their characteristics should be Cladistic Analysis family trees that show relationship between extinct and alive creatures All similar characters o Analogies o Homologies Shared primitive characters ancestral Unique to mammals eyes insects also have them Shared derived characters unique to a clade Unique to mammals body hair This is significant because these traits that are specific describe that part of the family tree The sequence of branching in a cladogram then represents the sequence in which evolutionary novelties shared derived characters evolved Cladistic Analysis Ingroup vs outgroup o Ingroup the group whose relationships we are trying to resolve o Outgroup a species or group known to have an older more recent common ancestor with the ingroup than the ingroup s most recent common ancestor An outgroup helps identify shared ancestral and shared derived characters unique to a clade All come from one line and break off part of a node marking a species Parsimony and Occam s Razor o Occum s Razor the simplest answer is the most likely answer o The most parsimonious tree is the one that requires the fewest evolutionary events appearance of shared derived characters o On this most parsimonious cladogram each key character originated evolved once Sometimes these are wrong dolphin goes with tuna or leopard Have to choose the least number of evolutionary traits Look at example in powerpoint Macroevolution and Phylogeny Sometimes the most parsimonious arrangement for one character is not the most accurate overall As you incorporate other data you have to change your thoughts Cannot tell age Don t confuse the age of a clade with the age of its component species The Hidden World of Microbes Microbes too small to be seen clearly without a microscope Prokaryotes range in size 0 2 1 0micrometers Unicellular eukaryotes range in size 10 100 micrometers How big is a micrometer 1 1 000 000 of a meter o The period is about 1000 micrometers The chloroplast of eukaryotic plant cells plasmids bacteria and cyanobacteria has circular chromosomes in structure Eukaryotic nuclear DNA is linear The mitochondria of eukaryotic cells is circular mitochondrial People have 2 genomes nuclear DNA linear mitochondrial DNA circular Plants have 3 genomes chloroplast circular nuclear DNA linear mitochondrial circular Mutualistic symbiotic relationship ecoli and colon of a human both benefit from living together Parasitic symbiotic relationship when human eats ecoli from deer meat one benefits and the other is harmed Influenza attacks the respiratory system in humans but the digestive system in birds Other biological entities not really living things cannot replicate on their own even smaller than bacteria o Not organisms o Viruses small 0 05 0 2 micrometers and come in many different shapes 1 Genome genetic information Can be either single stranded or double stranded DNA or RNA chicken pox varicella zoster double stranded DNA HIV single stranded RNA influenza single stranded RNA 2 Capsid protein coat which surrounds and protects 3 Envelope membrane phospholipid bilayer which genome surrounds the capsid Hijack cells highly specific for organism it infects Virus must 1 Find host cell 2 Gain entry 3 Release genome replicate 4 Release new viruses Viruses active inactive attenuated turn down not fully active Shouldn t get if
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