B2 - Classifying and Naming Organisms (Updated 2024) PDF

B2 - Classifying and Naming Organisms I can… Explain the fundamental principles of taxonomy and binomial nomenclature Classifying Organisms In order to discuss the various factors that influence population distribution and diversity, ecologists must have a consistent method of...

B2 - Classifying and Naming Organisms I can… Explain the fundamental principles of taxonomy and binomial nomenclature Classifying Organisms In order to discuss the various factors that influence population distribution and diversity, ecologists must have a consistent method of classification to refer to various species and their relatives Taxonomy: Practice of classifying living things Classifying Organisms All living organisms can be classified according to the three domains of life: Archaea: Ancient bacteria Bacteria: Bacteria that are not classified as Archaea Eukarya: Eukaryotic organisms (have a nucleus) Domains of Life Domain Characteristics Examples Archaea Prokaryotic cells (no nucleus) Halophiles Single-celled organisms Methanophiles Live in extreme environments (heat, pH, salinity) Can be autotrophs or heterotrophs Bacteria Prokaryotic cells (no nucleus) Cyanobacteria Single-celled organisms E. Coli Live in less extreme environments Can be autotrophs or heterotrophs Eukarya Eukaryotic cells (contain a nucleus) Plants Single-celled or multicellular organisms Animals Live in less extreme environments Protists Can be autotrophs or heterotrophs Fungi Classifying Organisms 8 levels (from general to specific) 1. Domain 2. Kingdom 3. Phylum 4. Class 5. Order 6. Family 7. Genus 8. Species *This system, not including domain classification, was developed by Carolus Linnaeus Consider This What organisms are bobcats most closely related to? Naming Systems Most organisms are classified according to a binomial nomenclature Their “official” name is a combination of their genus and species Ex. Humans are referred to as Homo sapiens ○ “Homo” is the genus name, while “sapiens” is the species name Naming Systems Binomial nomenclature: Method of naming organisms by using the genus and species name Scientific names are italicized Uses Latin & Greek words Ex. Castor canadensis (Castor = “beaver”, canadensis = “from Canada” Binomial Nomenclature Special rules for binomial nomenclature: 1. Genus: Can include several species First letter is always capitalized and can be written alone 2. Species: Can never be used alone Binomial Nomenclature Indicates similarities in anatomy, embryology, and evolutionary ancestry Suggests that different species are genetically related, for example: ○ North American black bear (Ursus americanus) ○ Grizzly bear (Ursus horribilus) ○ Alaskan brown bear (Ursus arctos) ○ Polar bear (Ursus maritimus) ○ Koala and panda bears do not belong to genus Ursus Changing Names With the ability to genetically sequence the DNA of any organism, we can now verify whether or not a particular organism is correctly classified Can compare an organism’s DNA to other organisms we suspect are related ○ Ex. Skunks have recently been removed from the family that contains weasels and have been placed in their own family Dichotomous Keys One of the easiest ways to classify an organism is to use its visible characteristics Dichotomous key: Use pairs of descriptions to simplify identification of an organism Dichotomous Keys Because organisms within the same family can look so similar, ecologists use dichotomous keys to help identify which species are present in a particular area Example Identify the tree species that leaf A is produced by.