Classification of Living Things
Taxonomy: The branch of biology that names and groups organisms according to their characteristics. (Does it have a backbone? Feathers? Gills? Flippers? Evolutionary History: Shows how an organism changed through the fossil record. What other organisms is it related to?
The first person to group or classify organisms was the Greek teacher and philosopher Aristotle more than 2000 years ago. (300 B.C.)
Aristotle’s system Plants: Based on size of stem. Animals: Based on where they lived.
Problems? 1. Not all organisms fit into Aristotle’s 2 groups (plants or animals) Ex: Bacteria Fungi
2. Common names can be misleading. Problems? 2. Common names can be misleading. Ex: A jelly fish isn’t a fish, but a seahorse is! Sea Cucumber sounds like a plant, but it’s an animal.
Problems? 3. Common names vary from place to place. Puma, mountain lion, cougar… 4. Different organisms have different names in different countries.
Solution? Some early scientists devised scientific names using long descriptions in LATIN. RED OAK Quercus foliis obtuse-sinuatis setaceo-mucronatis
Carolus Linnaeus: Devised a new classification system based on Morphology. (Organism’s form and structure) (1707-1778)
Grouped organisms into 7 different levels. Linnaeus’s System: Grouped organisms into 7 different levels. Each organism has a two part Latin Scientific Name. Kingdom Phylum Class Order Family Genus Species
Kingdom Animalia Phylum Chordata Class Mammalia Order Carnivora Family Felidae Genus Panthera Species leo
Binomial Nomenclature (2 name naming system) • 1st name= Genus • 2nd name= Species Vampire bat Desmodus rotundus
Modern Taxonomy
Modern Taxonomy Organizes living things in the context of Evolution.
Modern Taxonomy Scientists use different kinds of info to classify organisms: _Fossil record________ _Morphology_________ _Embryology_________ _Chromosomes______ _Macromolecules (DNA and Proteins)
Evolutionary history = _____________ 1. Fossil Record We can trace some changes over time through the fossil record. Evolutionary history = _____________ PHYLOGENY
2. Morphology Shape and Function
Morphology Homologous characteristics: :same embryological origin. :may have similar structure and function. Ex:bat wing and human arm. Homologous characteristics suggest a recent common ancestor.
Homologous Structures Bat wing and human arm develop from same embryonic structures
3. Embryology Animals whose embryos develop in a similar pattern may be related