Classification of Living Things PDF

Classification of Living Things Biodiversity - Biologists estimate that there are approximately 8.7 million different kinds of living things on Earth today with about 1.7 million classified. - This number keeps changing though - Roughly 10,000 species are discovered each year - Estimated 2...

Classification of Living Things Biodiversity - Biologists estimate that there are approximately 8.7 million different kinds of living things on Earth today with about 1.7 million classified. - This number keeps changing though - Roughly 10,000 species are discovered each year - Estimated 27,000 species go extinct each year  Types of Diversity - Structural/Ecosystem Diversity: the physical size, shape, and distribution of individuals in an ecosystem - Species Diversity: The variety and number of species in an ecosystem - Genetic Diversity: Genetic variability among individuals and organisms in an ecosystem What’s a Species? - Textbook definition: - “a group whose members are able to freely breed among themselves under natural conditions” - This can be a tricky definition because there are exceptions: - Hybridization: cross-breeding between species. Occurs occasionally - Asexual Organisms: don’t fit the definition neatly Taxonomy - Taxonomy is the science of identifying and classifying all organisms (living and fossil species) - Carl Linnaeus. The “father of taxonomy”, developed a system called binomial nomenclature to name species - This system uses two Latin words to give each species a unique name 1. Genus name 2. Species name Example: Orcinus orca Genus species Taxonomic Hierarchy (Levels) Taxonomy - All organisms are slotted into eight nested levels of taxonomic categories known as ranks - The ranks go from biggest to smallest - This is a hierarchical system Evidence Used for Taxonomy - Organisms have evolved to survive in their environment - Taxonomy helps us classify organisms to see how closely related they are - The relationship between two organisms is based on three types of evidence: 1. Anatomical evidence - do the structures of the organisms look the same? 2. Physiological evidence - do the proteins and enzymes in the cells work the same? 3. DNA evidence - how genetically closely related are the genes and the proteins they make  Check in: a. Which two species Common Order Family Scientific would you expect to Name Name share the most Orca Cetacea Delphinidae Orcinus orca features? River Otter Carnivora Mustelidae Lontra b. Which species would canadensis you expect to be least Mink Carnivora Mustelidae Neovison vison similar to the others? Siamese Cat Carnivora Felidae Felis domesticus c. What evidence is there Labrador Carnivora Canidae Canis lupus that otters share more Retriever features with mink Artic Carnivora Canidae Alopex lagopus than dogs do with Fox cats? What is a Domain? - A domain is the highest level of taxonomic classification - The three domains are Bacteria, Archaea, and Eukarya - Bacteria and Archaea are also the names of kingdoms - The domain Eukarya contains the other 4 kingdoms of Protista, Fungi, Plantae, and Animalia Domains - The domains are based on two types of cells - prokaryotes and eukaryotes - Bacteria and Archaea are prokaryotic cells - Remember that prokaryotic cells lack a nucleus and membrane bound organelles - All the organisms in the domain Eukarya have cells that evolved a nuclear membrane to protect their DNA and they have organelles 6 Kingdoms Classification Practice Review: 1. Which two organisms are Taxon House Cat Mountain Domestic Human most closely related? Lion Dog 2. What three taxa do all four organisms have in Kingdom Animalia Animalia Animalia Animalia common? Phylum Chordata Chordata Chordata Chordata 3. Which taxon includes organisms that have hair Class Mammalia Mammalia Mammalia Mammalia or fur and produce milk? Order Carnivora Carnivora Carnivora Primates 4. Which taxon includes Family Felidae Felidae Canidae Hominidae animals with backbones? Genus Felis Puma Canis Homo 5. What is the scientific name for each of the Species catus concolor lupus sapiens organisms above. Dichotomous Keys - A tool which uses a series of paired comparisons to sort organisms into groups. And eventually, classify them as their own species - The user must choose between two defining statements - Comparisons are usually based on physical characteristics, such as colour Dichotomous Keys... Can be a branching flow chart: Dichotomous Keys... Can be a series of paired descriptive choices: Tips for Using Dichotomous Keys: - Always read both choices, even if the first seems to be the logical one - Be sure you understand the meaning of the terms involved - If the choice is not clear, try both divisions. If you end up with two possible answers, read the descriptions of the two choices to help you decide. magnolia elm walnut spruce pine white oak chestnut holly 29  Dichotomous Key Practice How would we identify each of these?