190 likes | 645 Views
Classification. Book Chapter 18. What is a Species?. A species is a population of organisms that share similar characteristics and can breed with one another to produce fertile offspring ~1.5 millions species have been identified and named already
E N D
Classification Book Chapter 18
What is a Species? • A species is a population of organisms that share similar characteristics and can breed with one another to produce fertile offspring • ~1.5 millions species have been identified and named already • Scientists estimate there are between 2 and 100 million species yet to be discovered
Diversity of Life • Diversity of life • There are so many different species on Earth • Why are there differences? • Unity of life • All creatures have similarities/Common characteristics • Why are they so alike? • Taxonomyis the discipline of classifying organisms
Why Does Classification Matter? • By using a scientific name, everyone can be sure they are talking about the same organism • EX. Bird vs. Paradisaearudolphi
Assigning Scientific Names • By the eighteenth century, scientists realized that using common names was not working • Panther vs. Cougar vs. Puma vs. Mountain Lion • Scientists started using Greek and Latin to name organisms • At first, they used words to describe the organisms • Some names could be 20 words long!
Problems with Traditional Classification • Sometimes due to convergent evolution, organisms that are different from each other evolve similar body structures • These similarities made it difficult for scientists to decide how some organisms should be classified
How do dolphins cause confusion within traditional classification?
Carolus Linnaeus • 1707-1778 • “Father of Modern Taxonomy” • Swedish botanist, physician, and zoologist • Brought order to the process of naming species by binomial nomenclature
Binomial Nomenclature • In binomial nomenclature, each species is assigned a two-part name • The first word is capitalized, the second word is not • The first part of the name is the genus • The second part of the name is unique to the species
Linnaeus’s Classification • Each group or level of organization is called a taxon • Linnaeus’s system uses 7 taxonomic categories
Kingdom Phylum Class Order Family Genus Species
Evolutionary Classification • Grouping organisms based on their evolutionary history is evolutionary classification • Cladograms are diagrams that show the evolutionary relationship among a group of organisms
He’s Back! • When Darwin brought forth the idea of evolution, it shifted the way organisms are classified • Biologists now group organisms into categories that represent lines of evolutionary descent, not just physical similarities
Modern Day Descendants Distinctive Characteristics Common Ancestor
The Tree of Life • A domain is a larger, more inclusive group than a kingdom • There are 3 domains: • Domain Bacteria • Domain Archaea • Domain Eukarya