CLASSIFICATION Similarities and Differences
TEKS 8A: Students will define taxonomy and recognize the importance of a standard system to the scientific community 8B: Students will categorize organisms using a hierarchical classification system based on similarities and differences 8C: Students will compare the characteristics of taxonomic groups
CLADOGRAMS AND DICHOTOMOUS KEYS
CLADOGRAMS AND DICHOTOMOUS KEYS Cladograms are used to show the evolutionary history of an organism and its relationship to other organisms Similar to a family tree you can trace an organism s history through time, and see how closely related they are to other organisms
CLADOGRAMS AND DICHOTOMOUS KEYS How can we place newly discovered organisms into their correct spot on a cladogram? Nodes of the cladogram are areas where organisms diverged in their evolution Speciation Therefore, a cladogram is nothing but a series of choices o A dichotomous key is used to help identify organisms Based on a series of two choices o You read both choices, which will lead you to another set of choices until the organism is identified
DICHOTOMOUS KEY EXAMPLE
DICHOTOMOUS KEY EXAMPLE
CLADOGRAMS AND DICHOTOMOUS KEYS
CLADOGRAMS AND DICHOTOMOUS KEYS
CLADOGRAMS AND DICHOTOMOUS KEYS Example 1a: Four limbs Go to 2 1b: Does not have four limbs Fish 2a: Covered skin Go to 3 2b: Skin not covered Amphibian 3a: Birth via amniotic eggs Go to 4 3b: Live birth Mammals 4a: Feathers Aves (birds) 4b: No feathers Reptile
CLASSES OF ANIMALS Fish (vertebrate) No limbs (arms or legs) Covered in scales Lay unshelled eggs Amphibians (vertebrate) Four limbs Thin, uncovered skin Lay unshelled eggs Mammals (vertebrate) Four limbs Covered skin (in hair) Give birth to live young Reptiles (vertebrate) Four limbs Covered skin (in scales) Lay amniotic eggs Aves/Birds (vertebrate) Four limbs Covered skin (in feathers) Lay amniotic eggs Insects (invertebrate) Six limbs Exoskeleton Lay eggs Antenna & compound eyes
CLASSES OF ANIMALS
HOW WE CLASSIFY History and Naming
WHY DO WE CLASSIFY? https://vimeo.com/19796663 (0:00-1:33) Scientists currently estimate that there are approximately 8.7 million (+/ 1.3 million) organisms on the planet today A study published by PLoS Biology says 86% of all land species and 91% of marine species have yet to be discovered, described, and catalogued
VOCABULARY Species: a group of organisms that can interbreed and produce fertile offspring Taxonomy: the science of classification Binomial Nomenclature: a two-part scientific name consisting of the organisms genus and species
HISTORY OF CLASSIFICATION Aristotle classified organisms into two categories plants and animals However, this system did not allow for evolutionary relationships or organisms that did not fit into either the plant or animal category In the 1700 s, a new system was created by Carolus Linneaus Modern classification still uses Linneaus s system, but has been updated to show evolutionary relationships
CAROLUS LINNAEUS Created binomial nomenclature Organisms categorized into taxa groups based on specific criteria and shared characteristics
MODERN CLASSIFICATION Today taxonomists classify organisms based on Physical similarities Genetic similarities Biochemical similarities Behavioral similarities There are eight classification groups Domain (3) (Hemisphere) Kingdom (6) (Continent) Phylum (54) (Country) Class (State) Order (County) Family (City) Genus (Street) Species (~8.7 million) (House #)
MNEMONIC DEVICE Domain Kingdom Phylum Class Order Family Genus Species Dear King Philip Cried Out For Good Shoes
CLASSIFICATION LEVELS
RED FOX CLASSIFICATION
GRIZZLY BEAR CLASSIFICATION
CLASSIFICATION FOR HUMANS
CLASSIFICATION COMPARISON
NAMING ORGANISMS Scientists name organisms in order to assist in clarity and organization Why not use common names? Common names can vary from location to location for the same organism. Ex: cougars, pumas, mountain lions, and panthers are all the same organism Common names can be misleading. Ex: a starfish is not a fish, a mountain goat is not a goat, a guinea pig is not a pig, and a killer whale is not a whale
NAMING ORGANISMS There is only ONE scientific name for an organism Organism s scientific name = Genus species The correct way to write a scientific name Genus capitalized and species lowercase The whole name should be in italics or underlined
DOMAIN AND KINGDOM DESCRIPTIONS
DOMAINS AND KINGDOMS
THREE DOMAINS AND SIX KINGDOMS Each has a set of characteristics that bind the organisms in the group together These characteristics are not hard-and-fast rules, but more like guidelines
THREE DOMAINS AND SIX KINGDOMS 1. Archaea contains one kingdom (archaea) 2. Bacteria contains one kingdom (eubacteria) 3. Eukaryea contains four kingdoms (protists, fungi, plants, and animals)
DOMAIN ARCHAEA Kingdom Archaea Ancient prokaryotes Unicellular Cell walls Autotrophic OR heterotrophic Called extremophiles because they live in extreme environments Methanogens make methane gas Thermophile love heat (found in hot springs) Halophiles love salt Decomposers break down dead/decaying organisms
DOMAIN BACTERIA Kingdom Eubacteria Prokaryotic Unicellular Cell walls made of peptidoglycan Some are aerobic, some are anaerobic Most are heterotrophic, but a few are autotrophic Decomposers break down dead/decaying organisms More abundant than any other organism
DOMAIN EUKARYA All are eukaryotic Contains 4 kingdoms: protista, fungi, plantae, animalia
DOMAIN EUKARYA Protista Eukaryotic Some are unicellular and some are multi-cellular Some are autotrophic (make their own food), but some heterotrophic Some have cell walls, others do not Known as the odds-and-ends kingdom since these are the organisms that simply do not fit anywhere else
DOMAIN EUKARYA Fungi Eukaryotic Multi-cellular (except yeast) Have cell walls are made of chitin Heterotrophic Decomposers
DOMAIN EUKARYA Plantae Eukaryotic Multicellular Has a large central vacuole, chloroplasts, and cell walls (peptidoglycan) Autotrophic can make their own food using energy from the sun FYI: many organisms depend on plants because of their ability to make food
DOMAIN EUKARYA Animalia Eukaryotic Multi-cellular No cell walls Heterotrophic cannot make their own food, so they must eat plants, hunt, filter feed, or scavenge for food