Animal Classification, Phylogeny, and Organization (Systematics) Chapter 7

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.

DOMAIN KINGDOM PHYLUM Taxonomic Hierarchy CLASS ORDER FAMILY GENUS SPECIES Kids playing chicken on freeway get smashed

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 KINGDOM PHYLUM CLASS ORDER Broadest taxonomic category FAMILY GENUS SPECIES Broadest taxonomic category Added recently Not universally accepted

ALL eukaryotic organisms “True nucleus” Domains Eukaryota ALL eukaryotic organisms “True nucleus”

Prokaryotic microorganisms Domains Eubacteria Prokaryotic microorganisms “true” bacteria

Domains Archaea Prokaryotic microbes that live in extreme environments. (anaerobic) Most primative life-forms known

DOMAIN KINGDOM PHYLUM CLASS Robert H. Whittaker – Distinguished kingdoms based on cellular organization and mode of nutrition. There are five…… DOMAIN KINGDOM PHYLUM CLASS ORDER FAMILY GENUS SPECIES

Kingdoms of Life Monera Protist Plant Fungi Animal

Kingdoms Monera All prokaryotes! Single celled Make or absorb food -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 non-motile -chitin non-motile absorb food Mold, yeast, fungi

Kingdoms Plantae Eukaryotic multicellular cell wall non-motile -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

No two animals have the same name Homo sapiens 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 Characters 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.