UNIT 5A Classification & Kingdoms I. Classification a. Organize items so you can better understand and find them b. Based on Similarities c. Taxonomy: i. The Branch of Biology that groups and names organisms based on studies of their different characteristics ii. Taxonomist: Person who studies taxonomy i. Aristotle( B.C.)Greek Philosopher i. Recognized for creating Biological Classifications in two Groups: ii. Plants = herbs, shrubs, and trees (depending on size and structure) iii. Animals = according to characteristics (habitat and physical difference) ii. Linnaeus- Swedish Botanist ( ) i. Looked at physical and structural similarities of organisms and came up with relationships ii. Basis of modern classification systems d. Binomial nomenclature- two-word naming system to identify species in LATIN! 1. Genus (genera) consists of a group of similar species (Last Name) 2. Specific epithet- second word which describes a characteristic of an organism (First Name) i. Example: Humans (Common Name) Homo sapiens ( man who is wise) (Genus /specific epithet) ** Scientific names should be italicized in print and underlined when hand written **First letter of Genus name is upper case but the second word of the specific epithet is lower case II. Modern Classification 1. Compare external and internal structures of organisms 2. Compare geographical distribution and genetic makeup. 3. Group organisms that are living and extinct 1. Example: Bangle Tigers and Saber-tooth tigers 4. Group similar organisms in Taxon(singular)/Taxa (plural) III. Taxonomic Rankings a. Organisms are grouped in categories known as taxa i. These taxa range from having very broad characteristics to very specific characteristics b. The broader a taxon the more general the characteristics and more species it contains. i. Ex. The phylum chordata contains any creature that has a backbone. c. The narrower the taxon the more specific the characteristics and fewer species they will contain. i. Ex. The species, Homo sapiens, will only contain Humans d. The Different Taxa 1. Similar species will be grouped together further down this key. 2. Key moves from, more general to, more specific, top to bottom There are more organisms found in KINGDOM than in PHYLUM Taxonomic Classification of a Grizzly Bear IV. Kingdoms A. Six Major Kingdoms 1. Animals: 3 million species = 76% Euakryotic/ Sexually reproduce / Heterotrophs- eat other organisms 2. Plants: 0.5 million species = 15% Eukaryotic/ Sexual or asexual / Autotrophs- make own food / need sun and water 3. Fungi: 100,000 species = 5.6% Eukaryotic/ Have cell walls but dont make own food Heterotrophic - decomposers 4. Protists: 70,000 species = 2.8% Eukaryotic/ some have cell walls, some dont/ Some are heterotrophs some are autotrophs or both. 5. Archaebacteria 500 species = 0.03% Prokaryotic/ have cell wall /Live in harsh environments 6. Eubacteria 10,000 species = 0.3% Prokaryotic/ have cell wall Live everywhere else. UNIT 5C Classification & Evolution ii. Phylogenetic Classification Structural Similarities Cladistics i. A system of classification that is based on phylogeny (physical characteristics) ii. used to assume that as groups of organisms diverge, they retain some unique inherited characteristics Cladogram i. Branching diagram ii. Shows how very different organisms are similar to each other physically. Shared Characteristics iii. Breeding behavior Asexual or Sexual Time / Season when organism breeds iv. Geographical distribution Location of species on earth in relation to other organisms of similar kind. v. Chromosome comparisons The number of chromosomes (pieces of DNA) an organism has The shape/size of those chromosomes vi. Biochemistry DNA code How similar one organisms DNA is to another. V. What is Evolution? i. The theory that organisms will change (their DNA) genetically over time. a. It suggests that positive mutations have occurred to help a species survive. b. It suggests that all organisms that are present on earth today descended from a common ancestor. VI. What is Natural Selection? i. The idea that individuals with the most favorable variations for a particular environment survive and pass these traits on to offspring. ii. How Natural Selection works. 1. FIRST!!! Genetic variations must already exist within the genes of populations. 2. Some of those variations are more advantageous for survival and reproduction than others in certain environments. 3. Organisms tend to produce more offspring than can survive in an area 4. Overtime, offspring of survivors will make up a large proportion of the population. 1 -Organisms produce more offspring than can survive. Grasshoppers can lay over 200 eggs at a time. Only a small fraction of these offspring survive to reproduce. 2 -There is variation in nature, and certain heritable variationscalled adaptationsincrease an individuals chance of surviving and reproducing. In this population variation includes yellow and green body color. 3- Survival of the Fittest. Because their green color serves to camouflage them from predators, green Grasshoppers have a higher fitness than yellow grasshoppers and will survive to reproduce more often than do yellow grasshoppers in this environment. 4 Natural Selection - Green grasshoppers become more common than yellow grasshoppers in this population over time because: (1) more grasshoppers are born than can survive, (2) green individuals have a higher fitness in their current environment.