CK12.ORG FlexBooks - Chapter Detail - Classification - 24 views
-
Lesson 14.1: Form and Function Lesson Objectives Define taxonomy, and understand why scientists classify organisms. Describe Linnaean taxonomy and binomial nomenclature.
-
This phylogenetic tree is based on comparisons of ribosomal RNA base sequences among living organisms.
-
Scientific classification is a method by which biologists organize living things into groups. It is also called taxonomy. Groups of organisms in taxonomy are called taxa (singular, taxon). You may already be familiar with commonly used taxa, such as the kingdom and species. A kingdom is a major grouping of organisms, such as plants or animals. A species includes only organisms of the same type, such as humans (Homo sapiens) or lions (Panthera leo). The modern biological definition of a species is a group of organisms that are similar enough to mate and produce fertile offspring together. In a classification system, kingdoms, species, and other taxa are typically arranged in a hierarchy of higher and lower levels. Higher levels include taxa such as kingdoms, which are more inclusive. Lower levels include taxa such as species, which are less inclusive.
- ...29 more annotations...
-
Kingdom—This is the highest taxon in Linnaean taxonomy, representing major divisions of organisms. Kingdoms of organisms include the plant and animal kingdoms. Phylum (plural, phyla)—This taxon is a division of a kingdom. Phyla in the animal kingdom include chordates (animals with an internal skeleton) and arthropods (animals with an external skeleton). Class—This taxon is a division of a phylum. Classes in the chordate phylum include mammals and birds. Order—This taxon is a division of a class. Orders in the mammal class include rodents and primates. Family—This taxon is a division of an order. Families in the primate order include hominids (apes and humans) and hylobatids (gibbons). Genus—This taxon is a division of a family. Genera in the hominid family include Homo (humans) and Pan (chimpanzees). Species—This taxon is below the genus and the lowest taxon in Linnaeus’ system. Species in the Pan genus include Pan troglodytes (common chimpanzees
-
Kingdom Animal Organisms capable of moving on their own. Phylum Chordate Animals with a notochord (flexible rod that supports the body). Class Mammal Chordates with fur or hair and milk glands. Order Primate Mammals with collar bones, grasping hands with fingers. Family Hominid Primates with three-dimensional vision, relatively flat face. Genus Homo Hominids with upright posture, large brain. Species sapiens Members of the genus Homo with a high forehead, thin skull bones.
-
A subphylum is a division of a phylum that is higher than the class. An example of a subphylum is Vertebrates (animals with a backbone). It is a subphylum of the Chordate phylum (animals with a notochord). A superfamily is a taxon that groups together related families but is lower than the order. An example of a superfamily is Hominoids (apes). This superfamily consists of the Hominid family (gorillas, chimps, and humans) and the Hylobatid family (gibbons). Figure 6 shows species from both of these families of the Hominoid superfamily. A domain is a taxon higher than the kingdom. An example of a domain is Eukarya, which includes both plant and animal kingdoms. You can read more about domains in Lesson 14.3.
-
class Taxon that is a division of a phylum. family Taxon that is a division of an order. genus Taxon that is a division of a family. kingdom Major grouping of organisms, such as plants or animals. Linnaeus Swedish botanist who lived during the 1700s and is known as the “father of taxonomy.” order Taxon that is a division of a class. phylum Taxon that is a division of a kingdom. species Group of organisms that are similar enough to mate and produce offspring together. taxa Categories of org
-
ancestral traits Traits inherited from a common ancestor. clade Group of organisms that includes an ancestor species and all of its descendants. cladistics Method of making evolutionary trees based on comparisons of traits of ancestor and descendant species. cladogram Diagram showing evolutionary relationships within one or more clades. common ancestor Last ancestral species that two descendant species shared before they took different evolutionary paths. derived traits Traits that evolved since two groups shared a common ancestor. parsimony Choosing the simplest explanation from among all possible explanations. phylogenetic classification Classification of organisms on the basis of evolutionary relationships. phylogenetic tree Diagram representing a phylogeny. phylogeny Evolutionary history of a group of genetically related organisms.
-
Between 1866 and 1977, a total of four new kingdoms were added to the original plant and animal kingdoms identified by Linnaeus. The new kingdoms include Protist
-
archaea Domain that was formerly the Archaebacteria kingdom. bacteria Domain that was formerly the Eubacteria kingdom. domain Taxon higher than the kingdom. eukarya Domain that includes all four eukaryote kingdoms: plants, animals, protists, and fungi. eukaryote Organisms whose cells have nuclei. fungi Kingdom of eukaryote organisms such as mushrooms and molds. monera Original name of the kingdom that included all bacteria. prokaryote Organism whose cells lack nuclei. protista Kingdom of single-celled, eukaryote organisms such as protozoa, often called “protist
-
Define taxonomy.What contributions did Carolus Linnaeus make to taxonomy?List the order of taxa in Linnaean taxonomy, from most to least inclusive.What is binomial nomenclature?Create a hierarchical taxonomy to classify writing implements, such as pens and pencils. Use a diagram to show your taxonomy.Assume that a new organism has been discovered. It has a notochord, fur, forward-facing eyes, and grasping hands with fingers. In which taxa should the new organism be placed? Justify your answer.Explain why biologists need to classify organisms.Why was Linnaeus’ naming system such an important contribution to biology?
-
Lesson Summary Taxonomy is the scientific classification of organisms. Scientists classify organisms in order to make sense of the tremendous diversity of life on Earth. Linnaean taxonomy groups organisms in a hierarchy of taxa, based on similarities in physical traits. Linnaeus’ binomial nomenclature gives each species a unique two-word name.
-
Comparison of Phylogenetic and Linnaean Classification Systems Phylogenetic Classification Linnaean Classification 1. It treats all levels of a cladogram as equivalent. 1. It treats each taxa uniquely and has a special name or each (e.g., genus, species). 2. It places no limit on the number of levels in a ladogram. 2. It has fixed numbers and types of taxa. 3. Its primary goal is to show the process of evolution. 3. Its primary goal is to group species based on similarities in physical traits. 4. It is limited to organisms that are related by ancestry. 4. It can include any organisms without regard to ancestry. 5. It does not include a method for naming species. 5. It has a method for giving unique names to species.
-
Review Questions What is a phylogeny?Define cladistics.What does phylogenetic classification involve?Why are nucleic acid base sequences directly related to evolution?In cladogram 6 of Figure 6, explain how the five species are related to one.Identify an ancestral trait and a derived trait in mammals. Explain your answer.Explain why a cladogram represents only one hypothesis about how evolution occurred.Compare the advantages of Linnaean and phylogenetic classification systems.
-
This diagram shows how the three-domain system of classification is related to the six-kingdom system.
-
Comparing ribosomal RNA base sequences, Woese and his colleagues also showed that organisms belonging to Eukarya are more similar to Archaea than they are to Bacteria. Figure 6 is a phylogenetic tree based on their analysis. This tree places Archaea and Eukarya in the same clade (see Lesson 2). It represents the hypothesis that Archaea and Eukarya shared a more recent common ancestor with each other than with Bacteria.
-
-
Kladistik är enligt sidan ett livsträd där man delar in undergrupper och arter efter olika scheman. Detta skulle jag säga passar in på både Tree of Life och Linnes tankar om taxonomi. De som skiljer dessa åt är hur man har delat in grupperna. Linne tänkte att man delade in arter efter likheter fysiskt. Tree of Life delar istället in efter DNA och sådana likheter som kanske inte direkt syns. Dock är inget av dessa livsträd fullständiga eller helt och hållet organiserade, vi vet fortfarande inte hur det hänger ihop på alla punkter så att säga.
-
Skillnaden mellan denna klassificeringsmetod och religiösa sätt att skildra verkligheten är att man tror på någon högre kraft som påverkar naturen och bestämmer hur allt ska te sig. I det fallet är det svårt att avgöra om det är sanning eller ej då man aldrig kan se denna "högre kraft". Jag tycker att det sättet som Tree of life använder sig av är ett mer säkert sätt då man gör tester med DNA och ser skillnader och likheter mellan olika grupper.
-
En ny fråga som jag får är om Tree of Life verkligen stämmer också. Det finns flera luckor i deras taxonomi. Arter och högre grupper hamnar i samma kolumn och i vissa fall uppges att de är osäkra på om vissa led verkligen är besläktade med varandra. Det gör att man kan bli osäker på det som de uppger. Dock tror jag deras metod fungerar toppen, att undersöka DNA. Men frågan är om man kanske skulle kunna hitta ett bättre sätt att klassificera som ger bättre resultat och större sanningshalt.
-
-
-
Under Linné's art klassningsystem så grundades artindelningen i vissa huvudpunkter. En är Linnés taxonomi (fyllogentisk analys. Varm och kallblodiga djur) var en metod för att dela upp djuren. Det var effektivt att separera bort däggdjur och fågeldjuren från andra djur (främst reptiler. Ödlor, ormar etc.) Men det finns problem med denna metoden. Evolutionen kan ha utvecklat djur som ser och liknar andra djur väldigt mycket. Dock så kan djurens genetiska sekvenser skiljas helt ifrån varandra även om dom är lika. Exempel skulle kunna vara att en häst och en katt skulle vara nära besläktade bara för dom har 4 ben båda djuren. Lamarkismen skulle anknyta arterindelningen till att djuren knyts in till släkten som anknyter till liknande djur som lever i samma förhållanden kanske. Exempelvis en groda som liknar en ödla i ett tropiskt klimat. Men släktet kan lika gärna vara på andra sidan jordklotet men arten har spridit sig globalt. Lamarcismen stämmer alltså inte så mycket. Även om det i vissa fall kanske stämmer. Men då sker detta nog mer på gissning n på konkreta bevis grundade på genetik. Därför är en säker kontroll av djurens nukleida sekvenser det ända sättet att föredra för att få vara sker på vilka släkten djuren indelas i. Genom en undersökning i DNA så kan man kolla hur mycket nukleoiderna i DNA sekvenserna ser ut. En apa's DNA liknar till 96% till mänskligt DNA. Men de sista 4% gör att en chimpans är så olika oss. Att undersöka med teknologi inom DNA är en säker metod är att föredra.
-