Classification Chapter 17

Why classify organisms. currently there are 1 Why classify organisms? currently there are 1.5 million known species of living things

Taxonomy field of science that deals with classifying organisms according to their characteristics and evolutionary history

Early scientists had to use common names or scientific descriptions when referring to organisms common names – used by the people of an area, may not accurately describe an organism, vague, one organism might have several common names Example: jelly fish, ground squirrel, pine tree,… scientific descriptions – were long, written in different languages, did not indicate relationships Example: insect having 3 body segments, 6 legs, 2 pairs of wings, hairy abdomen,….

Early Classification Aristotle – 2000 BC devised a classification system divided living things into 2 groups…. PLANTS – divided into smaller groups based on their stem structure – herbs, shrubs, trees ANIMALS – divided into smaller groups based on their habitat – land, air, water

Early Classification Linnaeus - 1700’s - naturalist devised a classification system based on comparative morphology classification system had 7 taxonomic categories (called TAXONS) devised a way to give each organism a unique 2 word name

7 taxonomic categories = taxons Kingdom – composed of similar phyla or divisions largest group; most variety Phylum or Division – composed of similar classes Class – composed of similar orders Order – composed of similar families Family – composed of similar genera Genus – composed of similar species Species – composed of structurally similar organisms that naturally interbreed and produce fertile offspring smallest group; least variety

ACRONYM – to help you remember the order of the taxons kingdom - King phylum - Phillip class - Came order - Over family - From genus - Great species - Spain

classification of the American Crow Kingdom: Animalia Phylum: Chordata (with backbones) Class: Aves (birds) Order: Passeriformes (songbirds) Family: Corvidae (crows, jays) Genus: Corvus Species: brachyrhynchos

Binomial Nomenclature giving an organism a unique 2 word name, A SCIENTIFIC NAME consists of two words Genus – 1st word – capitalized species – 2nd word – lower case *written in latin or “latinized” *underlined or italicized

Why Latin? “dead” language is the basis for many of today’s languages no changes being made it is not in use today is the basis for many of today’s languages assures a unique name for each species

Scientific Names may tell you… geographic location of organism who discovered it how the organism looks Examples: Linnea borealis Odocoileus virginianus Felis domesticus

Lasionycteris noctivagans nocti = nocturnal vagans = wanderer nyct = night “wanderer at night” Silver-haired bat

Dichotomous Key “dividing into two parts” used to help identify an organism based on it characteristics at each step in a dichotomous key you have 2 choices

MODERN CLASSIFICATION Today, taxonomists classify organisms in such a way as to indicate evolutionary relationships. called phylogenetic classification Archaeopteryx – believed to be the ancestor of birds

Modern Taxonomy IS NOT BASED ON HABITAT!!!! Today, taxonomists use… comparative morphology fossil evidence embryological evidence chromosomal evidence biochemical similarities physiological similarities evolutionary relationships to determine the classification of an organism

PHYLOGENY = THE EVOLUTIONARY HISTORY (relationships) OF A SPECIES PHYLOGENETIC TREE = TREE OR DIAGRAM THAT REPRESENTS THE EVOLUTIONARY HISTORY OF A SPECIES

DERIVED CHARACTERS are used to help determine evolutionary relationships Derived Character - a feature (trait) that apparently evolved only within a specific groups of organisms examples…. jaws, lungs, claws, feathers, mammary glands,….

CLADOGRAM - diagram made by cladistic analysis that shows the evolutionary relationships of organisms cladistic analysis help to determine evolutionary relationships (phylogeny) so that phylogenetic trees are more “accurate”

2 Modern Systems of Classification Today, we use the 6 kingdom system However, because of differences in cellular structure and molecular/chemical structure, scientists have added a larger/broader taxon – called a domain – this is known as the 3 domain system

2 Modern Systems of Classification 3 domain system 6 kingdom system Domain archaea Kingdom archaebacteria Domain bacteria Kingdom eubacteria Domain eukarya Kingdom protista Kingdom fungi Kingdom plantae Kingdom animalia

Differences among Kingdoms Archaebacteria and Eubacteria: prokaryotic, unicellular Protista: eukaryotic, unicellular and multicellular Fungi: eukaryotic, cell wall of chitin, no chloroplasts, unicellular and multicellular, absorptive heterotrophs Plantae: eukaryotic, cell wall of cellulose, chloroplasts, all multicellular, autotrophic Animalia: eukaryotic, no cell wall, all multicellular, heterotrophic

BACTERIA are divided into 2 Kingdoms Archaebacteria and Eubacteria (previously classified together as kingdom Monera)

3 shapes spiral rod round

Bacteria…. Eubacteria and Archaebacteria many are saprophytic (feed on dead organic matter) many are parasitic (feed on living organic matter) among the first forms of life prokaryotic cells unicellular ONLY KINGDOMS lacking an organized nucleus and membrane-bound organelles Nostoc (cyanobacterium)

Methods of energy acquisition (or modes of nutrition) Some are capable of ….chemosynthesis Some are capable of ….photosynthesis Others are heterotrophic

Bacteria – Roles in the Environment some cause disease – INCLUDING strep throat, tooth decay, gum disease, flesh eating strep bacteria and many more… photosynthesis and oxygen production cyanobacteria (“blue-green bacteria”) contributed to formation of atmospheric oxygen by photosynthesis Cause spoilage of food food source (used to flavor foods such as …Yogurt, vinegar, cheese, buttermilk, sour cream Important in nutrient transfer convert atmospheric (gaseous)N into forms useable by plants and animals Lyme disease – carried by mammals and birds, transmitted by ticks to humans Many heterotrophic bacteria also cause diseases such as strep throat, rheumatic fever, cholera, gonorrhea, syphilis, and toxic shock syndrome. Bacteria can cause disease by destroying cells, releasing toxins, contaminating food, or by the reaction of the body to the infecting bacteria. Bacterial infections can be controlled by vaccinations and antibiotic treatments. Antibiotics interfere with some aspect of the replication of bacteria, and are produced by microorganisms such as fungi, that compete with bacteria for resources. Penicillin, the first antibiotic discovered, inhibits the synthesis of new cell walls in certain types of bacteria. However, the overuse of antibiotics during the past fifty years has led to natural selection favoring antibiotic resistance. There are reportedly more than 50 strains of antibiotic resistant bacteria, necessitating the development of new antibiotics and the frequent change of antibiotics in treatment.

Bacteria – Roles in the Environment decomposition saprophytic (decompose dead tissue) symbiotic (live within a host organism) These decomposing bacteria are often used in sewage treatment plants some oil deposits are attributed to cyanobacteria There are also oil eating bacteria – used to clean up oil spills Used in biotechnology applications- we can take human genes and insert them into bacteria – turning them into “factories” that then produce HUMAN INSULIN and HUMAN GROWTH HORMONE

Kingdom Archaebacteria (“old bacteria”) cell wall does not contain peptidoglycan have unusual lipids in cell membrane oldest and most primitive organisms known life’s extremists - occupy environments that “normal” organisms find too harsh

Archaebacteria….3 groups…. Methanogens - produce methane gas, found in soil, swamps, digestive tracts of animals Extreme Halophiles – live in high salt environments, found in salt lakes, Dead Sea Thermoacidophiles – live in hot, acidic environments, found in volcanic vents, hydrothermal vents

Kingdom Eubacteria (“true bacteria”) cell wall contains peptidoglycan includes most of the bacteria that affects our daily life including…. tetanus, strep throat, tooth decay, E. coli, salmonella, botulism, lyme disease, syphilis, and many more….

Kingdom Protista

Kingdom Protista Method of energy acquisition - heterotrophic and autotrophic Eukaryotic cells Found in freshwater, saltwater, soil, also live in other organisms because of great diversity, classification is difficult Euglena, diatoms, paramecium

3 groups of protista “animal-like” protists (called protozoans), include paramecium, amoeba “plant-like” protists (called algae) includes euglena, diatoms, dinoflagellates “fungus-like” protists includes slime molds and water molds

PARAMECIUM EUGLENA AMOEBA

Protista – Roles in the Environment photosynthesis and oxygen production food source (algae) animal feed, fertilizers algae sheets used in some Japanese dishes additive to puddings, ice cream, salad dressing, candy (carrageenan and alginate) Some can cause disease avian malaria, human malaria, amoebic dysentery

Protista and Red Tides Occurs when there is a population explosion of dinoflagellates neurotoxin is released shellfish eat dinoflagellates and concentrate toxin humans can be killed by eating shellfish contaminated by toxin http://www.redtide.whoi.edu/hab/rtphotos/noctiluca.jpg

Kingdom Fungi mushrooms, blights, rusts, molds, puffballs, morels, yeasts, truffles, toadstools, shelf fungi,….

Fungi Eukaryotic cells made up of hyphae – threadlike filaments that make up the body of a fungus mycelium= mass of hyphae no roots, stems or leaves no chlorophyll Method of energy acquisition: saprophytic or parasitic reproduce by spores cell walls contain chitin UNIQUE IN THAT THEY ARE absorptive heterotrophs Both multicellular and unicellular species

Roles of Fungi in the Environment Food Source mushrooms, truffles, morels, cheeses, bread, beer and wine Production of some Antibiotics Some are parasites of crops and plants cause loss of food plants, spoilage, infectious disease Dutch Elm Disease Chestnut Blight Benefit Wildlife food source, nest sites, hiding places and cover Symbiosis - Mutualism lichens (fungus + alga) mycorrhizae (fungus and plant roots)

Kingdom Plantae

Plants eukaryotic, multicellular, photoautotrophs cell wall with cellulose 2 major groups of plants nonvascular and vascular Fungi, lichens

Nonvascular Plants small – usually under 5” tall NO VASCULAR TISSUES - lack conducting cells for water and food likely were the earliest land plants liverworts, hornworts and mosses Fungi, lichens

Vascular Plants have specialized cells for transporting materials Xylem (for transporting water and mineral nutrients) Phloem (for transporting sugars from leaves to the rest of the plant) pines, cacti, grasses, trees, flowers, …..

Roles of Plants in the Environment food source generate oxygen provide habitat for humans and wildlife American chestnut, late 1800s

invertebrates and vertebrates Kingdom Animalia multicellular heterotrophic Eukaryotic cells no cell wall 2 main groups invertebrates and vertebrates

Invertebrates (animals without a backbone) sponges, jellyfish, corals, insects, worms, rotifers, comb jellies,…

Vertebrates animals with a backbone (of bone or cartilage) 5 groups of vertebrates - fish, amphibians, reptiles, birds, mammals

Roles of Animals in the Environment food source most serve as predators in some capacity – and limit populations of other organisms scavengers “shape” habitats for other wildlife

Viruses – not living Do have genetic material and some other characteristics of cells but do not exhibit all the characteristics of life However, biology usually involves a study of viruses because they infect cells

How are Viruses different from Bacteria? Subcellular Intracellular parasite No nucleus No organelles have genetic material Have a protein coat (capsid) Bacteria Prokaryotic cells No nucleus Have organelles Have genetic material Have a cell membrane and many have a cell wall

Viruses infect all groups of organisms – however, they are very specific Plant viruses infect a specific plant or group of related plants Human viruses only infect humans Bacterial viruses infect bacteria

is a virus that infects a bacterium BACTERIOPHAGE is a virus that infects a bacterium

Other viral shapes…

Let’s Review This characteristic separates which kingdoms…. All members are heterotropic? All members are autotrophic? Contains both heterotrophic and autotrophic members? All members prokaryotic? All members eukaryotic? Have chloroplasts? Have a cell wall? All members unicellular? All members multicellular? Contains both unicellular and multicellular members? Autotrophic = Plantae Heterotrophic = Fungi, Animalia Heterotrophic and Autotrophic = Monera, Protista