Animal Classification, Phylogeny, and Organization Chapter 7 (Systematics) There are between 1.5 and 2 million species or “kinds” of animals And between 4 and 30 million more species to be discovered & classified Classification: The ordering of organisms into groups on the basis of their relationships Taxonomy: The science of naming organisms Systematics: Determining evolutionary relationships of organisms Karl von Linné (Carolus Linnaeus) (1707-1778) Swedish Botanist that recognized that different species could be grouped into broader categories based on shared characteristics Created binomial naming system Modern classification system used today Persian Cat Shares characteristics with other domesticated cats (tabby, hairless) Domesticated cats share characteristics with other types of cats (bobcat, puma) Which share characteristics with dogs, bears, pigs Mammals! Hierarchical system of classification: Arranged organisms into an ascending series of groups based on relatedness. These major groups are called taxa. Taxonomic Hierarchy DOMAIN KINGDOM PHYLUM CLASS ORDER FAMILY GENUS SPECIES Taxonomic Groups Hierarchy of Relatedness Each group contains animals having more in common with each other than with the members of any other equivalent category DOMAIN KINGDO M PHYLUM CLASS ORDER FAMILY GENUS SPECIES Domains Eukaryota ALL eukaryotic organisms “True nucleus” Domains Eubacteria Prokaryotic microorganisms “true” bacteria Domains Archaea Prokaryotic microbes that live in extreme environments. (anaerobic) Most primative life-forms known Robert H. Whittaker – Distinguished kingdoms based on cellular organization and mode of nutrition. DOMAIN KINGDOM PHYLUM CLASS ORDER FAMILY GENUS SPECIES There are five…… Kingdoms of Life Monera Protist Plant Fungi Animal Kingdoms Monera All prokaryotes! Single celled -peptidoglycan Make or absorb food Bacteria and cyanobacteria (blue-green algae) Kingdoms Protista Eukaryotic single cells or colony of cells Protozoa, amoeba, paramecium Kingdoms Fungi Eukaryotic multicellular cell wall -chitin non-motile absorb food Mold, yeast, fungi Kingdoms Plantae Eukaryotic multicellular cell wall -cellulose non-motile produce food -photosynthetic Higher plants, multicellular algae Kingdoms Animalia Eukaryotic multicellular lacks cell wall motile ingest food Vertebrates, Invertebrates Animal Kingdom Subdivided into more than 30 phyla (pl) Each phylum divided into classes Each class into orders Each order into families Each family into genera (pl) Each genus into species A common pond crayfish is classified as: Kingdom Animalia Phylum Arthropoda Class Crustacea Order Decapoda Family Cambaridae Genus Procambarus Species P. acutus Every phylum must have at least one class, order, etc.. More specialized levels of taxonomy deal with further subdivisions such as superfamily or subfamily, suborder, or subspecies Linnaeus’ system for naming species known as binomial nomenclature (two names) or “scientific name” Universally accepted No two animals have the same name Homo sapiens 1st word: Name of genus (capitalized) 2nd word: Name of species (lower case) Entire word italicized or underlined (Latin origin) Homo sapiens Homo sapiens H. sapiens The scientific name for a crayfish is Procambrus acutus Animal Systematics Goal: To arrange animals into groups that reflect evolutionary relationships. There are 3 types of groups. Monophyletic group: Groups with single ancestral species and its decendents. Polyphyletic group: Members can be traced to separate ancestors. Paraphyletic group: Some but not all members of a lineage. Cladogram Cladograms Taxa Depicts a sequence in the origin of derived characters. Characters Patterns of Animal Organization Animal Symmetry How parts of an animal arrange around a point or axis Asymmetry: Absence of a central point or axis around which body parts are equally distributed (protists, sponges) Animal Symmetry How parts of an animal arrange around a point or axis Radial: Divides into similar halves by more than two planes (sea anemone, jellyfish) Animal Symmetry How parts of an animal arrange around a point or axis Bilateral: Arrangement of body parts so that a single plane divides the animal into left & right mirror images (vertebrates) Cephalization: Formation of a distinct head Bilateral Symmetry Bilateral Symmetry Anterior Posterior Head end Tail end Bilateral Symmetry Dorsal Ventral Back of an animal Belly of an animal Bilateral Symmetry Medial Lateral Midline of the body Sides of the body Bilateral Symmetry Superior Inferior Above a point of reference Below a point of reference Bilateral Symmetry Distal Proximal Far from the middle or point of attachment Close to the middle or point of attachment Radial Symmetry Aboral Oral End opposite the mouth End containing mouth Diploblastic Organization •Simplest tissue level organization •2 layers: •Ectoderm-outer layer, gives rise to epidermis. •Endoderm-gives rise to the tissue that lines the gut. Triploblastic Organization •3 layers •Ectoderm-outer layer of body wall •Endoderm-lines the gut •Mesoderm-gives rises to supportive, contractile and blood cells.