Biological Classification By Dr Biological Classification By Dr. Sunetra Kshirsagar (Lokmangal Science & Entrepreneurship College, Wadala)
Group the following in any way you would like, but justify your grouping! Frogs Bears Ants Spiders Bacteria Humans Dolphins Sharks Mushrooms Pine Trees
Why do we Classify? Recognize similarities between living things (DNA, biomolecules, cells) Group organisms according to those similarities Taxonomy: the science of classifying organisms
Who created Taxonomy? Aristotle was the first scientist to group organisms based on physical characteristics Carolus Linnaeus (1707 – 1778) a Swedish botanist , came up with the current system.
Classification Groups The groups (largest to smallest) Domain Kingdom Phylum Class Order Family Genus Species A sentence to help you remember! Dear King Philip Came Over For Good Soup
Levels of Classification: The 3 Domains (based on cell type)
Levels of Classification: The 5 Kingdoms Based on… Cell type Number of Cells Mode of Feeding
Final 7 Levels of Classification 1 is Largest- 7 is Smallest
Examples of Classification Common Pond Amoeba KINGDOM: Protista PHYLUM: Sarcomastigophora CLASS: Sarcodina ORDER: Granulopodea FAMILY: Amoebidae GENUS: Amoeba SPECIES: Amoeba proteus
Examples of Classification Humans KINGDOM: Animalia (animal cells, heterotroph) PHYLUM: Chordata (all vertebrates) CLASS: Mammalia (all mammals) ORDER: Primata (all primates) FAMILY: Hominidae (bipedal primates) GENUS: Homo (humans and neanderthals) SPECIES: Homo sapiens (humans only!)
Binomial Nomenclature Binomial Nomenclature - the formal system of naming species. (Bi = two, nomial = names) The last two classification groups (genus and species) are used to create a unique name for each species. Because we use two groups for the name, similar species will have similar names. Example: Ursus arctos (Grizzly Bear) and Ursus maritimus (Polar Bear) In a species name, only the Genus is capitalized. Latin is the language used to make these names. Since it is no longer spoken anywhere, we do not have to worry about it changing.
What evidence is used to classify? Homologous (similar) Structures Ex: The bones in a bat’s wing are almost the same as the bones in a human hand Similar Behaviors Ex: All mammals nurse their young Similarities in genes (DNA or protein sequence) Ex: Human and Primate DNA is 99% similar
Evidence for Classification Fossil Record: Past organisms studied through fossils Ex: Trilobites and horsehoe crabs Embryology: similar development patterns in unborn of different species Ex: Dolphin limb buds Hybridization: ability to successfully interbreed different species. Ex: Zorse