Chapter 17 Classification

Evaluate the history, purpose, and methods of taxonomy. Section Objectives: Evaluate the history, purpose, and methods of taxonomy. Explain the meaning of a scientific name. Describe the organization of taxa in a biological classification system.

How Classification Began Biologists want to better understand organisms so they organize them by classification—the grouping of objects or information based on similarities

TAXONOMY Taxonomy is the branch of biology that groups and names organisms based on studies of their different characteristics.

Linnaeus’s system of binomial nomenclature Linnaeus developed a method of grouping organisms based on physical & structural similarities of organisms. Modern classification systems use a two-word naming system called binomial nomenclature. It is written in Latin.

Binomial nomenclature A genus (genera) consists of a group of similar species. It is the first word in the species name and is capitalized. The second word, which sometimes describes a characteristic of the organism, is called the species identifier. It is not capitalized.

Writing the scientific name The scientific name (species name) for each species is a combination of the genus name and species identifier. Genus capitalized, species is not It is written in italics and in latin (underline it when you write it). Ex. Homo sapiens, Acer ruber

How Living Things Are Classified A group of organisms is called a taxon (plural taxa). The taxa are Kingdom (Kelly) Phylum (Payton) Class (came) Order (over) Family (for) Genus (good) Species (soup)

Order of Taxonomic rankings The broader a taxon, the more general its characteristics, and the more species it contains. The very largest, and the most broad is the Kingdom The next to smallest taxon is a genus—a group of similar species that have similar features and are closely related. The smallest taxon is species. Organisms that look alike and successfully interbreed belong to the same species.

Dichotomous Key A key is made up of sets of numbered statements. Each set deals with a single characteristic of an organism, such as leaf shape or arrangement.

Compare the six kingdoms of organisms. Section Objectives Compare the six kingdoms of organisms.

From 5 to 6 Kingdoms of Organisms Monera Archaebacteria Eubacteria Protists Fungi Plants Animals

Prokaryotes These organisms are cells that lack distinct nuclei bounded by a membrane, are microscopic and unicellular. Some are heterotrophs and some are autotrophs 2 kingdoms of prokaryotic organisms: Archaebacteria and Eubacteria.

Kingdom Archaebacteria (monerans) Ancient bacteria Live in extreme conditions (extreme heat, salt, acidity) Most of these environments are oxygen-free making this organism anaerobic.

Kingdom Eubacteria (monerans) True bacteria They live in most habitats except the extreme ones. Most common Although some cause diseases, such as strep throat and pneumonia, most bacteria are harmless and many are actually helpful.

Cyanobacteria A “blue – green bacteria, photosynthetic; lives in salt and fresh water and on land Prochlorobacteria contains chlorophyll a & b

4 Phyla of Monerans 1. Eubacteria 2. cyanobacteria 3. Archaebacteria 4 4 Phyla of Monerans 1. Eubacteria 2. cyanobacteria 3. Archaebacteria 4. Prochlorobacteria 3 Basic Bacteria Shapes 1. Bacillus – rod shaped 2. Cocci – round shaped 3. Spirilla – spiral shaped

Monerans Reproduction Methods 1 Monerans Reproduction Methods 1. Binary Fission: replication of DNA and divides in ½ (asexual) 2. Conjugation: bridge of protein between two cells where genetic material is passed from one to another

Importance of Monerans - Used to make cheese, yogurt, sour cream, sauerkraut, vinegar, wine, and pickles - Used to clean up oil spills - Used to synthesize medications and chemicals - Used to remove wastes and poisons from water -Symbiotic relationship with the other 4 kingdoms Ex: E. Coli helps us digest food and in turn it has food, shelter, and transportation

Bacterial Diseases 1. Diptheria 2. Tuberculosis 3. Tetanus 4 Bacterial Diseases 1. Diptheria 2. Tuberculosis 3. Tetanus 4. Syphilis 5. Bubonic Plague 6. Typhoid Fever

Viruses Not a part of the classification system NOT alive Only act alive while within a living organism (when they reproduce) Cannot be stopped by antibiotics Ex. Common cold, flu, HIV

Viruses Viruses are non – cellular particles made of genetic material and protein that can invade living cells Virus structure/characteristics - Capsid – core of nucleic acid surrounded by a protein coat. The core has DNA or RNA, but never both

Virus structure/characteristics Cont Virus structure/characteristics Cont. - Bacteriophage: viruses that invade bacteria; has a capsid, nucleic acid core, and a tail - Viruses have varied shapes such as rods, cubes, and tadpole – like - Examples of viruses: Polio, HIV, Tobacco Mosaic Virus (TMV)

Virus Structure/Characteristics Cont Virus Structure/Characteristics Cont. - A virus can infect every kind of organism, but are specific to each organism (plant virus can’t infect an animal) - A virus must have a host to reproduce - Viruses infect by attacking a host and injecting its DNA into the cell

Viruses Structure/Characteristics Cont Viruses Structure/Characteristics Cont. - A virus grows by coping the host cell DNA, taking over the cell, and eventually the host cell bursts spreading the virus to all cells (this process takes about 20 min!) -A virus must have a host to live, feed and reproduce, can’t live outside the cell

Viral Diseases 1. Smallpox 2. Measles 3. Mumps 4. Flu 5. AIDS 6 Viral Diseases 1. Smallpox 2. Measles 3. Mumps 4. Flu 5. AIDS 6. Rabies 7. Colds 8. Polio

Kingdom Fungi: Earth’s decomposers Organisms are heterotrophs that do not move from place to place. A fungus is either a unicellular or multicellular eukaryote that absorbs nutrients from organic materials in the environment. They have a cell wall (made of chitin) but do not make their own food.

Fungi Characteristics -Eukaryotic, heterotrophic, multicellular (except yeast) - Saprophytic – obtain food from decaying organic matter - Parasitic – live directly on the body of a plant or animal

Fungi Reproduction Asexual through production of spores or fragmentation of the hyphae Sexually through (+) hyphae mating type joining with (-) mating type forming a gamete Mycelium – many tiny filaments Hyphae – individual filament of a mycelium

Phyla of Fungi 1. Oomycota – “protist – like fungi” produce motile spores Ex: water molds 2. Zygomycota – “common molds” Ex. Molds on cheese, bread, and meat 3 Types of Hyphae 1. Rhizoids – Like roots that penetrate the surface 2. Stolens – run along the surface 3. Sporandiophores – form sporangia

Phyla of Fungi Cont. 3. Ascomycota – “sac fungi” largest group, reproduce by budding which is the formation of smaller cell from a larger one Ex: yeast 4. Basidiomycota – “club fungi” Ex. Mushroom; the basidium is a spore producing structure, one mushroom can produce 1 billion spores

Phyla of Fungi Cont. 5. Deuteromycota – “imperfect fungi” ; have characteristics similar to all of the other phyla, reproduction has never been observed, Ex: ringworm, athletes foot, tomato blight, black spot of roses - Lichen – symbiotic relationship between a fungus and a bacteria, they help plants grow, orchids will not grow without a lichen

Ecological Advantages of Fungi 1 Ecological Advantages of Fungi 1. Decompose and recycle living material 2. Replace used elements and nutrients back into the soil 3. Used in baking and brewing 4. Serves as a food source for animals

Diseases Caused By Fungi 1 Diseases Caused By Fungi 1. Potato Blight – potato looks normal but inside is a spongy sac of dust 2. Wheat Rust – kills wheat before grains can be produced 3. Mildew – affects fruit 4. Athlete’s foot – highly contagious and easily spread

Kingdom Protista (protists) Very diverse with similar characteristics. A protist is a eukaryote that lacks complex organ systems and lives in moist environments. Some protists are unicellular, others are multicellular. Some are plantlike, animal-like, or funguslike

Kingdom Plantae All of the organisms are multicellular, photosynthetic eukaryotes. They do not move (non-motile.) A plant’s cells usually contain chloroplasts and have cell walls composed of cellulose. Instead of phyla, we call their classification Kingdom–DIVISION–class–order–family-genus-species

Kingdom Animalia Animals are multicellular heterotrophs. Nearly all are able to move from place to place. Animal cells do not have cell walls. Their cells are organized into tissues that, in turn, are organized into organs and complex organ systems.

The Six Kingdoms Summary Archaebacteria & Eubacteria contain only unicellular prokaryotes. Commonly called Kingdom Monera Protista contains eukaryotes that lack complex organ systems. (many are unicellular eukaryotes) Fungi includes heterotrophic eukaryotes that absorb their nutrients. Plantae includes multicellular eukaryotes that are photosynthetic. Animalia includes multicellular, eukaryotic heterotrophs with cells that lack cell walls.