Transcript Taxonomy
Taxonomy and Phylogeny SB3. Students will derive the relationship between single-celled and multi-celled organisms and the increasing complexity of systems. b. Compare how structures and function vary between the six kingdoms (archaebacteria, eubacteria, protists, fungi, plants, and animals). c. Examine the evolutionary basis of modern classification systems. Taxonomy Taxonomy is the science of classification and nomenclature, especially of organisms How do scientists classify organisms? •by their morphology– how they look •by their phylogeny– their evolutionary relationships •by their DNA In a lot of ways, classification is like sorting the organisms. Autotrophs heterotrophs Cell wall No cell wall History of Taxonomy • Aristotle (350 BC) – 2 groups: plants and animals; vertebrates and invertebrates • Carl Linnaeus (1735) – Developed the hierarchy of classification – Developed a standardized binomial nomenclature Hierarchy of Classification • • • • • • • Kingdom Phylum Class Order Family Genus Species General, Inclusive Specific, Exclusive “Kings Play Chess on Fluffy Green Sofas” How was life grouped? • Plantae and Animalia (1735) • Plantae, Animalia, and Protista (1866) • Plantae, Animalia, Protista and Monera (1938) • Plantae, Animalia, Protista, Monera, and Fungi (1969) • Plantae, Animalia, Protista, Eubacteria, Archaebacteria, and Fungi (1977) How is life grouped now? • Domains Bacteria, Archaea, Eukaryota (1990) now incorporate the kingdoms • Bacteria (Eubacteria) • Archaea (Archaebacteria) • Eukaryota – Protista – Fungi – Plantae – Animalia An example… • In the ONE Kingdom Animalia… – There are over 7,700,000 different kinds of animals • So the kingdom is subdivided into at least 30 phyla – The largest phylum is Arthropoda, which contains ~85% of all animals • So the phylum is subdivided into ~15 classes – The largest class is Insecta, which includes over 5 million different creatures An example… • So the class is divided into ~34 orders – The largest order is Coleoptera (beetles), which includes 25% of all animal types • So the order is divided into ~170 families – One of the families, Coccinellidae (lady beetles), includes about 5000 types • So the family is divided into ~360 genera – One genus, called Coccinella, includes about 6000 different types, or species – Coccinella septempunctata Kingdom Phylum Class Order Family Genus Species Animalia Arthropoda Insecta Hymenoptera Apidae Apis mellifera What organism do you think this might be? Kingdom Phylum Class Order Family Genus Species Animalia Chordata Mammalia Primates Hominidae Homo sapiens What organism do you think this might be? Writing a scientific name • Always use genus & species names. • Must be underlined (in books they’re in italics) • Genus name is capitalized, species name is not! Examples: Homo sapiens Escherichia coli Pinus aristata Canis lupus • • • • • • • • • Panthera leo Panthera tigris Panthera pardus Canis lupus (and Canis domestica) Pan troglodytes Ovis aries Rattus norvegicus ; Rattus rattus Perca fluviatalis Carcharodon carcharias • • • • • • • • Boa constrictor Gorilla Giraffus Hippopotamus amphibius Bison bison Equus zebra Tyrannosaurus rex Elephas maximus What makes a species? • Look similar, have similar traits, and similar habitats. • Can interbreed and produce fertile offspring. Housecat Mountain Lion Kingdom Animalia Animalia Phylum Chordata Chordata Class Mammalia Mammalia Order Carnivora Carnivora Family Felidae Felidae Genus Felis Felis Species domesticus concolor Sometimes hybrids can form. • A hybrid is a cross between two very similar organisms– in all the same groups except for species. • Example: horse + donkey = mule • Mules cannot produce their own offspring. The Phylogenetic Tree of Life Cladistics • Cladistics is a method of classifying organisms based on shared characteristics that can be traced to common ancestors Cladistics • Here is an example of a cladogram for vertebrates Cladistics • Let’s see how to put one together… https://www.youtube.com/watch?v=46L_2RI1k3k Archaea • Prokaryotes • Ancient bacteria Able to survive harsh environments Thermoacidophiles: heat & acid Methanogens: methane halophiles: salt Bacteria • Prokaryotes • Typical bacteria Protista (every living thing that is NOT a bacterium, fungus, plant, or animal) Protists are classified according to how they acquire nutrients: • animal-like: heterotrophic, predatory • plant-like: photosynthetic • fungus-like: heterotrophic, absorptive Fungi– heterotrophic, cell walls of chitin, uni- & multicellular yeast Plantae– autotrophic, cell walls of cellulose, most are multicellular Animalia– all multicellular, heterotrophic, no cell walls