Topic Classification

What is Taxonomy? Systematics is the study of the diversity of life and its evolutionary history Systematics is combinaton of several sciences: 1.Taxonomy is science of naming and arranging living organisms into groups 2.Phylogeny is the evolutionary history of an organism or group

Goals of Taxonomy Three important goals: 1.Sort out closely related organisms into individual species 2.Assign a single universal name to all living organisms –Necessary to facilitate communication between all scientists worldwide 3.To place all living organisms into groups with real biological meaning.

Benefits of Taxonomy Species Identification – a system allows us to quickly identify organisms Predictive value – if several members of a group have a common trait, another species will probably have that trait too Evolutionary links – species in the same group probably share a common ancestor – helps indicate how they evolved

The Beginnings of Classification The first classification scheme was developed by Aristotle about 2000 years ago

Aristotle’s System Artistotle grouped organisms into: Plants And Animals

Changing the System Aristotle’s system was used until the 1400s –At that point “modern,” science was beginning to realize that system was too simplistic –Too often names for species varied from location to location and did not accurately describe the organism.

Carolus Linneaus Swedish Biologist who developed the basis for the classification system still in use today (mid 1700s) Utilized morphology (structure and function) to classify all living organisms

Linneaus’s System Linneaus created a “filing,” system for grouping organisms Hierarchy of increasingly more general categories: –Species are grouped into genera ( sing. genus) –Genera into families –Families into orders –Orders into classes –Classes into phyla (sing. phylum) –Phyla into kingdoms 5.5.2

Each group is called a taxon (plural taxa) Individual species are classified into a series of taxa – each one larger than the previous one Linneaus’s System 5.5.2

An Example - Human Classification Kingdom: Animalia –Phylum: Chordata Class: Mammalia –Order: Primate »Family: Hominidae Genus: Homo Species: sapien Larger group Smaller group 5.5.2

Another Example - Corn Classification Kingdom: Plantae –Phylum: Magnoliophyta Class: Liliopsida –Order: Cyperales »Family: Poaceae Genus: Zea Species: mays Larger group Smaller group 5.5.2

Linneaus’s System Linneaus assigned each species a two- part scientific name – binomial nomenclature Why mostly Latin or Greek? First name – Genus Second name – species 5.5.1

Binomial Nomenclature Canis familiaris 5.5.1

Binomial Nomenclature Rules for naming organisms: 1.The genus name is always upper- case. 2.The species name is always lower- case 3.Italics are used if the name is printed (typed) 4.Handwritten names are underlined with two separate lines

Modern Classification Linneaus only created two kingdoms for living organisms – plants and animals – why? Modern taxonomists argue about the number of kingdoms – five or six –Prokaryote (monera) – archaebacteria and eubacteria? –Protoctista (protist) –Fungi –Plantae –Animalia

Kingdom Plantae All organisms in Kingdom Plantae have the following characteristics: –Multicellular –Eukaryotic –Photosynthetic autotrophs –Almost all terrestrial Plants are divided into divisions (instead of phyla) based on evolutionary characteristics 5.5.3

Division Bryophyta Display evolutionary adaptations that helped bryophytes move from water to land: –Covered with a waxy cuticle – why? However, bryophytes are NOT totally independent of water. –Flagellated sperm must “swim,” to egg for fertilzation to occur –No vascular tissue – must absorb water from surface instead of absorbing from roots Moss are commonly found in damp, shady areas 5.5.3

Division Bryophyta 5.5.3

Division Filicinophyta First group of vascular plants: –Evolved as a means to obtain all required resources –Xylem and phloem transport resources between distant organs: Soil and roots provide minerals and water Above ground provides light for leaves and photosynthesis Includes over 12,000 species of ferns –Located in tropical and temperate forests 5.5.3

Division Filicinophyta 5.5.3

Division Coniferophyta Includes ~ 550 species of large trees including pines, firs, spruces, and redwoods All produce seeds in cones Most use wind pollination for reproduction. Almost all conifers are evergreens Most conifers have needles – leaves modified to prevent water loss 5.5.3

Division Angiospermophyta Angion means “container,” – seeds are enclosed in fruits Includes ~ 235,000 species of flowering plants May rely on wind, birds, insects, and even mammals for pollination and reproduction

Kingdom Animalia All organisms in Kingdom Animalia have the following characteristics: –Eukaryotic –Multicellular –Heterotrophic

Phylum Porifera Includes sponges Characteristics: no body symmetry, no tissues, no organs; hermaphrodites; filter feeders; sessile 5.5.4

Phylum Cnidaria Includes corals, jellyfish, and sea anemone Characteristics: stinging cells for food and protection; two-way digestive tract; radial symmetry; drifters or sessile 5.5.4

Phylum Platyhelminthes Includes flatworms like planaria, flukes, and tapeworms. Characteristics: distinct head region (cephalization); bilateral symmetry; most are parasites; two-way digestive tract; no heart or lungs; flat shape - why? 5.5.4

Phylum Annelida Includes earthworms, marine worms, and leeches. Characteristics: segmented; well developed nervous, digestive, and circulatory systems; one-way digestive system

Phylum Mollusca Includes snails, clams, octopus and squids. Characteristics: bilateral symmetry; one or more shells; soft bodies; most are aquatic 5.5.4

Phylum Arthropoda Includes insects, arachnids (spiders), and crustaceans Characteristics of all arthropods: exoskeleton made of chitin; jointed appendages; segmented body; open circulatory system Molting – process of shedding and exoskeleton and growing a new one to grow larger

Insects The largest group of all animals (more than 1 million species) Characteristics: three body segments (head, thorax, and abdomen); six legs; live in water and land

Crustaceans Include lobsters, shrimp, crayfish, crabs, and barnacles. Characteristics: aquatic; two body segments (cephalothorax and abdomen); gills 5.5.4

Arachnids Include spiders, scorpions, mites, horseshoe crabs, and ticks Characteristics: 2 body segments; eight legs; book lungs 5.5.4