Classification of Organisms Zoe Gilligan / Biology 111 / Mrs. Gallant
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Cladistics
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The image on the cover of this magazine is an empty cladogram, which scientists now use for classification and organization. The example you see pictured to your left is an animal cladogram, which classifies and organizes animals from the most simple to the most complex based on shared derived characteristics tracing back to a common ancestor.
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! ! ! Molecular Clocks ! !
Involved with genetics, molecular clocks are the rate at which mutations are accumulated (occurring in a clock-like fashion), which are used to measure evolutionary changes and diversity. Through this way of classification, scientists have been able to delve further into the details of the origin of modern humans, the human and ape connection, and so on and so forth.
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! ! ! DNA and RNA Comparisons !
DNA — deoxyribonucleic acid — is what contains the genetic information in cells, used for the development and functioning of all living organisms. One of the major structural differences between DNA and RNA is sugar, with the 2-deoxyribose in DNA being replaced in RNA with ribose. DNA replicates, transcribes itself into RNA, and RNA makes proteins. Scientists can use data from both RNA and DNA sequences — as opposed to just physical characteristics — for classification.
! ! Radioactive Dating
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This method concentrates on finding dates of origin. Scientists use the technique of radioactive dating to date matter, such as rocks and carbon. Through the detection of radioactive flaws (which occur when the matter is first formed), they are able to find the time from where it is.
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! Aristotle
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A scientist and philosopher from Classical Greece, many of the concepts, methods, and techniques we use today are based on the discoveries and foundations of Aristotle. Aristotle classified animals based on their similarities. He divided all animals into two groups: “blood animals” and “non-blood animals”. “Blood animals” had five classifications, which were mammals, birds, whales, reptiles, and fish. “Non-blood animals” were otherwise known as cephalopods and included insects, scorpions, plant-like animals, animals enclosed in shells, and crustaceans. While his work is not accurate to modern standards, it has remained the primary basis of biology for thousands of years after his death, ultimately and irrevocably altering the thinking of Western civilizations.
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! ! Embryology !
This biological branch of study investigates the development of gametes (sex cells), the processes of fertilization and reproduction, and the evolution of embryos, zygotes, and fetuses. While this may not be the best means of classification in modern times, scientists still use it for classification in regards to the development of embryos and how closely organisms can be in their evolutionary lineage.
! ! ! Structural Information Theory
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Structural Information Theory (SIT) surrounds the idea of the way humans organize what they see into objects and object parts, with a main focus on interpretations, rather than on underlying processes. SIT gave rise to many visual occurrences, such as brightness contrast, neon illusions, and transparency. It also extends to societal and visual patterns like interest and beauty. These visual patterns are what scientists use for classification.
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Linnaeus
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Also known as the father of taxonomy, Carl Linnaeus was a Swedish physician, zoologist, and botanist alive from 1707 to 1778. Linnaeus’ vision for an accurately organized system was published in his Systema Naturae (1735). His taxonomy includes three kingdoms, with further division into classes, then into orders, families, genera, and species. His three kingdoms were Animal, Vegetable, and Mineral.
Again, while Linnaeus’ system may not be as precise as the 21st century one, he’s still the person who pioneered taxonomy. Overall, today we still feel the impact he has on science through his basis for biological nomenclature, and so on and so forth.
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“Science is the systematic classification of expression.” - George Henry Lewes