Chapter 18 Classification

18-1: Finding Order in Diversity Key Concepts How are living things organized for study? What is binomial nomenclature? What is the Linnaeus’s System of classification? Vocabulary Taxonomy Binomial nomenclature Taxon

18-1 Vocabulary Kingdom Phylum Class Order Family Genus Species

18-1: Why Classify? To organize into groups that have meaning Name and group the organism Use a logical system Teachers or a mechanic High school or a automobile Biology or a foreign maker Honors or an electrical system To assign each organism a universally accepted name Binomial nomenclature: genus species name Linnaeus system: seven classification names

18-1: Linnaeus Hierarchical system consists of seven major levels, (KPCOFGS) The prefix Super is designated for a more general description Ex: Superorder is more general than order, but more detailed than Subclass The suffix Sub is designated for a more detailed description Ex: Suborder is more detailed than order, but less than Superfamily

Questions How are living things organized for study? Describe the system for naming species that Linnaeus developed. What are the seven categories developed by Linnaeus? Why do scientist avoid using common names when discussing organisms? What is binomial nomenclature?

18-2: Modern Evolutionary Classification Key concepts How are evolutionary relationships important in classification? How can DNA and RNA help scientists determine evolutionary relationships? Vocabulary Phylogeny Evolutionary classification Derived character Cladogram Molecular clock

18-2: Which similarities are most important? Taxonomic groups above the level of Species are “invented” by researchers who decide how to distinguish between species Grouping these characteristics by KPCOFGS Determining subjective characteristics may be problematic Descriptions of big versus small or words like curved Any of the characteristics may be open to interpretation

18-2: Evolutionary Classification Phylogeny: the evolutionary relationship between organisms Biologists now group organisms by Physical similarities Lines of evolutionary descent

18-2: Classification using a Cladogram Derived characteristics: these appear in the most recent parts of a lineage, but not in its older members Cladograms are a type of evolutionary tree The Theory of Evolution Where do We come from? barnacle crab

18-2: Similarities in DNA and RNA Genes of many organisms show important similarities at the molecular level DNA of one organism can be compared to another Similar genes Human have a gene that codes for myosin proteins Yeast have a gene that codes for a myosin protein

18-2: DNA Evidence Common ancestors Divergent evolution The more similar the DNA, the more recently the two organisms share a common ancestor Changes in DNA have several causes Divergent evolution A change in the organism due to many possible factors

18-2: Molecular Clocks DNA may also be used to compare how long organisms have been evolving independent of each other. Mutations occur at a fairly regular rate Some are expressed Some are not expressed Different rates for different organisms

Questions How is information about phylogeny useful in classification? Evolutionary information? How are genes used to classify organisms? What are the characteristics behind the use of a Cladogram? Is there a gene that suggests that yeast and humans have a common ancestor? What is a molecular clock?

Classification Taxonomy Is the science of classification Scientists need a system of grouping organisms, to find order in diversity Classification of a species is based on the evolutionary history of a species (ancestors/relatives!)

Domains are determined by

Note the two bacteria domains, (Kingdoms), at the bottom and the four Eukaryotic Kingdoms above. This system has changed and evolved from a system that included everything in two Kingdoms, (Plants and Animals)

Classification Six Kingdoms determined by Cell type – eukaryotic or prokaryotic Cell structures & cell wall composition Number of cells – uni or multi cellular Energy – heterotroph or autotroph

Questions What are the six kingdoms? What are the three domains? Why was Monera divided? How are the Kingdom Fungi different from the Kingdom Plantae? Which Kingdoms only include Prokaryots? Which Kingdoms include only Autotrophs?