Part 3 Classification and Biodiversity Ch. 18 Part 3 Classification and Biodiversity

Largest hierarchy of classification is DOMAIN System for biologists to arrange organisms into groups Categories = easier to remember Taxonomy Study and practice of classification Involves placing organisms into a series of taxonomic units called TAXA which form a hierarchy Each different organism is assigned a SPECIES Similar species are grouped into the same GENUS Similar GENERA (plural) are grouped into FAMILIES Similar families are grouped into ORDERS Similar orders are grouped into CLASSES Similar classes are grouped into PHYLUMS Similar phylum are grouped into KINGDOMS Largest hierarchy of classification is DOMAIN

So how do we classify??? Domain - Eukarya

Domains Broadest category of classification 1970’s Scientists needed a new category to distinguish between extremophiles and normal bacteria Three main domains Domain Archaea: unicellular prokaryotes that live in extreme environments (very hot or very cold, extremely acidic or basic) Extremeophiles Domain Bacteria: All other unicellular prokaryotes Domain Eukarya: Organism made up of eukaryotic Cells Includes 4 kingdoms: Protists, Fungi, Plants, Animals (and Monera)

Still some confusion among scientists over this one…

Consists of 1 MAJOR Kingdom Archaeabacteria Domain Archaea Extremophiles Currently, there are some living in less extreme areas of the ocean Prokaryotic More in common with Domain Eukarya than Genes coding for ribosomes very similar to those genes found in eukaryotes Domain Bacteria No nucleus Size similar to bacteria No membrane-bound organelles DNA is circular chromosome WITH histones present Contain Plasmids 70S ribosomes Smaller than eukaryotes 80S ribosomes, BUT similar structure to eukaryotic ribosomes Cell wall ALWAYS present (not made of peptidoglycan) Divides by BINARY FISSION Exist as single cells or groups of cells Similar metabolism to normal bacteria Transcription similar to eukaryotic transcription

Consists of 1 MAJOR Kingdom Domain Bacteria Prokaryotic (no nucleus) Small size 0.5 to 5 um in diameter Range between largest virus and smalled eukaryote DNA is circular chromosome with NO histones Plasmids present No membrane-bound organelles present 70S ribosomes Cell wall always present Contains peptidoglycan NOT cellulose Divides by binary fission Exists as single cell or groups of cells Consists of 1 MAJOR Kingdom Eubacteria

Domain Eukarya Cells contain a nucleus Membrane-bound organelles DNA arranged in LINEAR chromosomes WITH histones 80S ribosomes Mitochondria and chloroplasts 70S ribosomes Chloroplast and mitochondrial DNA is circular Great Diversity in how they exist Unicellular Colonial multicellular Cell division by MITOSIS Asexual and Sexual reproduction Consists of 4 MAJOR Kingdoms Protoctista Fungi Plantae Animalia

Kingdom Protoctista Any eukaryote that is not fungi, plant, or animal Consists of wide range of organisms PROTOZOANS (simple animals) Similar to animal cells NO cell wall ALGAE (seaweeds) Similar to plant cells Have cell wall and chloroplasts Strong argument to classify these as PLANTS Single-celled Exists as single cell or group of cells

Kingdom Fungi All heterotrophic Use organic compounds made by other organisms for energy source Decomposers  energy obtained from dead and decaying organism Parasitic  feed on host Confused with plants b/c they are NON-MOTILE Wide range in size (some microscopic) Eukaryotic NO chlorophyll and do NOT use photosynthesis Reproduce by SPORES Simple body forms Unicellular HYPHAE  long threads with or without cross walls Compacted hypahe make up larger body forms like mushrooms Contain cell walls made of CHITIN NO cilia or flagella

Kingdom Plantae ALL multicellular ALL photosynthetic (AUTOTROPHIC) Differentiated tissues and organs ALL photosynthetic (AUTOTROPHIC) Eukaryotic (nucleus) Complex bodies Above ground Branched Few types of specialized cells SOME cells have chloroplasts and use photosynthesis Cells contain LARGE, permanent vacuoles for SUPPORT Cell walls made of CELLULOSE May have flagella Male gametes in some types of ferns

Kingdom Animalia Eukaryotic (nucleus) ALWAYS MULTICELLULAR Differentiated and specialized cells Differentiated into tissues and organs ALL Heterotrophic Contain NERVOUS SYTSEM Important in communication Do NOT have chloroplasts and cannot use photosynthesis Exception: some coral polyps with protoctists living in tissues Small, temporary cell vacuoles (exocytotic vacuoles, food vacuoles, lysosomes)NO cell walls Cells sometimes have cilia and flagella

Viruses Microorganisms Range in size from 20-300 nm (50x smaller than average bacteria) Visible with electron microscope NO cell structure No membrane No cytoplasm No ribosomes Consist solely of: Self-replicating DNA or RNA molecule Protective coat of proteins Capsid  protein coat Capsomere  proteins embedded in capsid When free in environment: They are infectious No metabolism Must use machinery of host cells to copy their genetic material Use energy from host cell to do these things Taxonomic classification Based on diseases that viruses cause Type of genetic material they contain

DNA RNA Types of Viruses Nucleic Acid Example Host Disease 1 2 Number of Strands Example Host Disease DNA 1 Canine parvirus type 2 Dogs Canine parvovirus African mosaic virus Cassava plants Mosaic virus 2 Varicella zoster virus (VZV) Humans Chicken pox RNA Rotavirus Gastroenteritis Morbillivirus Measles Tombaco mosaic virus (TMV) Tomato, tobacco, pepper Mosaic disease HIV/AIDS