Lec.1 Animal Taxonomy for veterinary medicine PDF

Animal Taxonomy  Course Specifications Relevant Program: Bachelor Degree of Vet. Science Department offers the program: Veterinary medicine Department offers the course: Zoology Departments, Faculty of Science At the end of this course, students shall be able...

Animal Taxonomy  Course Specifications Relevant Program: Bachelor Degree of Vet. Science Department offers the program: Veterinary medicine Department offers the course: Zoology Departments, Faculty of Science At the end of this course, students shall be able to: 1- Explain and discuss the general scheme of animal classification and the general characteristics of the major phyla. 2- List some example for the major phyla, their anatomical structure, life cycle, economical importance, ecological and medical importance. 3- Identify and classify some of local animal belong to the studied phyla.  Contents Subject No. of hours Lect. Pract. Introduction, Simple explanation of the classification of animal 1 _ kingdom into the main phyla Protozoan phyla. 1 2 phylum Porifera 1 2 phylum Cnidaria 1 2 phylum Platyhelminthes 2 4 Phylum Nematoda (Aschelminthes) 1 2 phylum Annelida 1 2 phylum Arthropoda 2 4 phylum Mollusca 2 4 phylum Echinodermata 1 2 phylum Chordata 1 2  Animal Taxonomy The branch of zoology concerned with the description, identification, nomenclature and classification of animals Therefore, the animal taxonomy means: an arrangement of animals into groups has relationships and similarities.  History 1. Aristotle (384-322 B C): Classify animals according to: their way of living, their habitat and their body parts.  History 2. Ray (1627 - 1705): define the “species”: A group of animals that have similar morphological characteristics and can breed freely with each other to produce fertile offspring resemble their parents. 3. Linnaeus (1707-1778): who classify animals on the base of structures and published the principles of the current classification scheme. He divided animals into seven taxonomic ranks: species, genera, families, orders, classes, phyla and kingdom. He established the Binomial nomenclature which means that each species has a name composed of two words. The 1st is the genus name and the 2nd is the species. The two words should write in italic letters.  Examples: The scientific name of human beings: Homo sapiens (L.) The Egyptian toad: Bufo regularis The housefly: Musca domestica Taxonomists have the option of subdividing the previous seven ranks even further to recognize more than seven taxa (super- class, sub-class, infraclass, super-order, sub-order, etc.) for many particular groups of organisms. For very large and complex groups, such as fishes and insects, these additional ranks are needed to express different degrees of evolutionary divergence. Nominclature: Common names: Each country has its common names for well-known animals. Even in one country there are local names for a species. Thus a species may have many names and counted as many animals that make confusion between people of different nationalities or even within one country Scientific names: Binomial nomenclature. Linnaeus adopted the use of two names for each species the genus name and the species name. These words are from Latin or in Latinized form because Latin was the language of scholars and universally understood. The generic name is usually a noun. Some of the basic Rules of Nomenclature in the International Code of Zoological Nomenclature: the system of Nomenclature adopted is the as binomial system as described by Linnaeus (1758), which is modified in some cases to include a trinomial nomenclature when a subspecific name is used. The scientific name of a species is a combination of two names, the first is a generic name which must begins with capital letter and the second is the specific name which must always begins with a lower-case letter. A scientific name must be written in Latin letters or latinized word. The family group name is formed by adding idea to the stem of the name of the type genus and the subfamily name by adding inae.  Major Divisions of Life From Aristotle’s time to the late 1800s, every living thing was assigned to one of two kingdoms: plant or animal. However, the two kingdom system was problematic. Although it was easy to place rooted; photosynthetic organisms such as trees, flowers, and mosses, among the plants and to place food-ingesting, motile forms such as worms, fishes, and mammals among the animals, unicellular organisms presented difficulties. Some forms were claimed both for the plant kingdom by botanists and for the animal kingdom by zoologists. For example is Euglena which is motile, like animals, but has chlorophyll and photosynthesizes like plants.  unicellular forms Several alternative systems have been proposed to solve the problem of classifying unicellular forms. In 1866 Haeckel proposed the new kingdom Protista to include all single-cells organisms. But there are important differences between the anucleate bacteria and cyanobacteria (prokaryotes) and all other organisms that have cells with membrane-bound nuclei (eukaryotes) were recognized. ‫الخاليا حقيقةالنواة‬ ‫الخاليا بدائية النواة‬ Eukaryotic Cells Prokaryotic cell They possess a nuclear membrane as well as membrane They lack a nuclear membrane as well any other bound organelles in their cytoplasm. membrane covered organelles in their cytoplasm. This type of cells has linear DNA. Their genetic material This type of cells has circular DNA, no chromosomes in has chromosomes and can be found in Plant & Animal Cells their genetic material and it can be found in Bacteria & Blue-. Green Algae.  Major Divisions of Life In 1969 R. H. Whittaker proposed a five-kingdom system that incorporated the basic prokaryote-eukaryote distinction.  In 1969 R. H. Whittaker proposed a five-kingdom system that incorporated the basic prokaryote-eukaryote distinction. 1. kingdom Monera contained the prokaryotes 2. kingdom Protista contained the unicellular eukaryotic organisms (Protozoa and unicellular eukaryotic algae) The multicellular organisms were split into three kingdoms on the basis of mode of nutrition and other fundamental differences in organization. The kingdom Plantae included multicellular photosynthesizing organisms, higher plants, and multicellular algae. 3. kingdom Plantae Plantae included multicellular photosynthesizing organisms, higher plants, and multicellular algae 4. kingdom Fungi contained the yeasts, and fungi that obtain their food by absorption. 5. kingdom Animalia Includes the invertebrates (except the protozoa) and the vertebrates Most of these forms ingest food and digest it internally, although some parasitic forms are absorptive. The classification scheme  Basic characteristics of animal classification 1) Number of body cells: acellular & cellular 2) Organization: Mesozoa, Parazoa and Eumetazoa. 3) Germ layers: Diploblastica & Triploblastica. 4) Coelom: Acoelomata, Pseudocoelomata and Coelomata Besides, other characteristics are useful in classification: 5) Symmetry, asymmetry, radial, bilateral. 6) Segmentation, 7) Appendages, 8) Skeleton, 9) Sexes  Organization: Mesozoa, Parazoa and Eumetazoa. Mesozoa “missing link” between protozoa and metazoa. These minute, ciliated, wormlike animals represent an extremely simple level of organization. All mesozoans live as parasites in marine invertebrates, and the majority of them are only 0.5 to 7 mm in length. Most are composed of only 20 to 30 cells arranged basically in two layers. The layers are not homologous to the germ layers of higher metazoans. Germ layers: Diploblastica & Triploblastica.  Coelom: A fluid-filled cavity acts as a hydrostatic skeleton for soft-bodied animals and surrounded completely by the mesoderm. There are a few triploblastic animals that completely lack any sort of body cavity. These animals are known as acoelomates. Acoelomata, Pseudocoelomata and Coelomata Symmetry, asymmetry, radial, bilateral.