NIS - BIOLOGY Lecture 84 – Lecture 85 Domains and Kingdoms Ozgur Unal 1

Domains 2  Can you name the taxonomic categories?  The broadest category  domain  There are 3 domains:  Bacteria  Archaea  Eukarya  Within these domains there are 6 kingdoms:  Bacteria, Archaea, Protists, Fungi, Plantea and Animalia

Domains 3  Organisms are classified into domains according to the cell type and structure.  They are also classified into kingdoms according to cell type, structure and nutrition.  This 3-domain and 6-kingdom classification system has been in use for less than 3 decades.  Before 1970s  5 kingdoms  In 1970s  new organisms discovered  archaea (unicellular prokaryotes significantly different than bacteria)

Domain Bacteria 4  Domain Bacteria has one kingdom  Kingdom Bacteria  Bacteria  prokaryotes whose cell walls contain peptidoglycan.  Peptidoglycan is a polymer that contains two kinds of sugars that alternate in the chain.  The amino acids of one sugar are linked to the amino acids in other chains  netlike structure that is porous and strong.

Domain Bacteria 5  Bacteria are a diverse group that can survive in many different environments.  Some are aerobic, some are anaerobic..  Some are autotroph, most are heterotroph..  Bacteria are more abundant than any ther organism.

Domain Archaea 6  Domain Archaea has one kingdom  Kingdom Archaea  More ancient that bacteria, but more closely related to eukaryote ancestors.  Their cell walls do not contain peptidoglycan.  They have some of the same proteins that eukaryotes do.  Diverse in shape and nutrition..  Some are autotrophic and most are heterotrophic..  They are called extremophiles because they can live in extreme environments  Example: Staphylothermus marinus is found deep in ocean thermal vents and can live in water temperatures up to 98 o C.

Domain Eukarya 7  Domain Eukarya has 4 kingdoms  Kingdom Protista, Kingdom Fungi, Kingdom Plantae and Kingdom Animalia  The organisms in this domain are all eukaryotes (unicellular or multicellular)

Domain Eukarya 8 Kingdom Protista:  Members of Kingdom Protista are called protists.  Protists are eukaryotic organisms that can be unicellular, colonial or multicellular.  Protists do not have organs.  The members of this kingdom are not necessarily similar to each other  they don’t fit in any other kingdoms

Domain Eukarya 9 Kingdom Protista:  They are classified into three broad groups.  Plantlike protists  algae perform photosynthesis (e.g. Kelps)  Animal-like protists  protozoans are heterotrophs (e.g. Amoebas)  Funguslike protists  There is also Euglenoids, which have both plantlike and animal-like characteristics.  Euglenoids are usually grouped with plantlike protists because they have chloroplast.

Domain Eukarya 10 Kingdom Fungi:  A fungus is a unicellular or multicellular eukaryote that absorbs nutrients from organic materials in its environment.  Members of Kingdom Fungi are:  heterotrophic  lack motility  have cells walls, which contain chitin  structural support  A fungus consists of a mass of threadlike filaments  hyphae  Hyphae are responsible for growth, feeding and reproduction.  There are more than 70,000 known species of fungus.

Domain Eukarya 11 Kingdom Fungi:  Fungi are heterotrophic.  Some are parasites..  Others are saprobes..  Fungi secrete digestive enzymes into their food source and then absorb digested materials directly into their cells.  Fungi that live in a mutualistic relationship with algae are called lichens.  Lichens get their food from the algae that live among their hyphae.

Domain Eukarya 12 Kingdom Plantae:  There are more than 250,000 species of plants in Kingdom Plantae.  These organisms form the base of all terrestrial habitat. Why?  All plants are multicellular have cells walls composed of cellulose.  Most plants have chloroplast  autotrophs  Few plants are heterotrophic.. Example?

Domain Eukarya 13 Kingdom Plantae:  All plants possess cells that are organized into tissues.  Many plants have organs  root, stem and leaves  Plants lack motility  Some plants, however, have reproductive cells called flagella, which propel them through water.

Domain Eukarya 14 Kingdom Animalia:  Members of this kingdom are called animals.  More than 1,000,000 species identified.  All animals are:  Heterotrophic  Multicellular eukaryotes  Animal organs are organized into tissues, organs and organ systems.  They live in water, land or in the air.  Most animals are motile.

Viruses 15  A virus is a nucleic acid surrounded by a protein coat.  Viruses do not possess cells, not are they cells and are not considered to be living.