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Opener Chapter 7 Chapter 7 Animal Classification, Phylogeny, and Organization Slide 2 Common names Crawdads, crayfish, or crawfish? English sparrow, barn sparrow, or a house sparrow? Problem with common names Vary from region to region Common names often does not specify particular species Slide 3 Binomial system of Nomenclature brings order to a chaotic world of common names Universal Clearly indicates the level of classification No two kinds of animals have the same binomial name Every animal has one correct name International Code of Zoological Nomenclature Slide 4 Genus begins with a Capital letter Entire name italicized or underlined Homo sapien or H. sapien Slide 5 The three domains Arhaea- prokaryotic microbes live in extreme environments, inhabit anaerobic environments Reflect the conditions of early life Archaea the most primitive life form Archaea give rise to two other domains Eubacteria- true bacteria and are prokaryotic microorganisms Eukarya- include all eukaryotic organisms, diverged more recently thus more closely related to archae (protists, fungi, plants and animals) Slide 6 Figure 7.2 (b) Slide 7 Kingdom of Life 1969 R. Whittaker- five kingdom classification System of classification that distinguished b/w kingdoms according to cellular organization mode of nutrition Slide 8 Figure 7.2 (a) Slide 9 Monera- bacteria and cyanobacteria are prokaryotic Slide 10 Protista- single or colonies of eukaryotic cells (Ameoba, Paramecium) Slide 11 Plantae- eukaryotic, multicellular, and photosynthtic. Have cell wall, and usually nonmotile Slide 12 Fungi-eukaryotic and multicellular. Have cell wall and nonmotile. Mode of nutrition distiguishes fungi from plant- fungi digest extracellularly and absorb the breakdown products Slide 13 Animalia- eukaryotic and multicellular, usually feed by ingesting other organisms, cell lack cell walls, and usually motile Slide 14 Text devoted to animals Except for Chapter 8 Animal like protists (Amoeba and Paramecium) The inclusion of protozoa is part of a tradition Once considered a phylum (Protozoa) in the animal kingdom Slide 15 Pattern of Organization Asymmetry i.e. ameoba Symmetry Radial symmetry- tube coral pulp Bilateral symmetry- insects Slide 16 Figure 7.7 Asymmetry red encrusting sponge Slide 17 Figure 7.8 Radial symmetry tube coral pulp Slide 18 Part 2 Slide 19 Bilateral animals Bilateral symmetry = important evolutionary advancement Important for active, directed movement Anterior, posterior ends One side of body kept up (dorsal) vs. down (ventral) Slide 20 Directed movement evolved with anterior sense organs cephalization Cephalization specialization of sense organs in head end of animals Slide 21 Bilateral Symmetry Divided along sagittal plane into two mirror images sagittal= divides bilateral organisms into right and left halves Slide 22 Anterior= head end Posterior= tail end Dorsal= back side Ventral= belly side Slide 23 Symmetry, fig. 7.9 Median= sagittal Slide 24 Other Patterns of Organization may reflect evolutionary trends Unicellular (cytoplasmic)- organisms consist of single cells or cellular aggregates, provide functions of locomotion, food acquisition, digestion, water and ion regulation, sensory perception and reproduction in a single cell. Slide 25 Cellular aggregates consist of loose association, cells that exhibit little interdependence, cooperation, or coordination of function Some cells may be specialized for reproduction, nutritive or structural function Slide 26 The analogy of a clock Can be used to place major events in the Earths history in the context of the geological record Figure 26.10 Land plants Animals Multicellular eukaryotes Single-celled eukaryotes Atmospheric oxygen Prokaryotes Origin of solar system and Earth Humans Ceno- zoic Meso- zoic Paleozoic Archaean Eon Billions of years ago Proterozoic Eon 1 2 3 4 Algea fossils ~500 million years ago Slide 27 Larger organisms do not appear in the fossil record Until several hundred million years later Chinese paleontologists recently described 570- million-year-old fossils That are probably animal embryos 150 m200 m (a) Two-cell stage (b) Later stage Slide 28 The Colonial Connection The first multicellular organisms were colonies Collections of autonomously replicating cells Figure 26.16 10 m May Lead to Cell Specialization Slide 29 Organisms can have more than one tissue layer Diploblastic- two layers Slide 30 What about Tripoblastic three layers? Slide 31 Diploblastic Organization- Two tissue layers Cells are organized into tissues in most animal phyla Body parts are organized into layers derived from two embryonic tissue layers. Ectoderm- Gr. ektos, outside + derm, skin gives rise to the epidermis the outer layer of the body wall Endoderm- Gr. Endo, within, gives rise to the gastrodermis that lines the gut Slide 32 Mesoglea- between the ecto and endo and may or may not contain cells Derived from ecto and/or endo Cells form middle layer (mesenchyme) Layers are functionally inderdependent, yet cooperate showing tissue level organization i.e. feeding movements of Hydra or swimming movements of a jellyfish Slide 33 Figure 7.10 Slide 34 The Triploblastic (treis, three +blaste, sprout) Animals described in chapters 10-22 Tissues derived from three embryological layers Ectoderm- outer layer Endoderm- lines the gut Mesoderm- meso, middle, Third layer between Ecto and Endo Give rise to supportive cells Slide 35 Figure 7.11 Diploblastic Triploblastic Diploblastic or Triploblastic? Slide 36 Triploblastic animal Slide 37 Most have an organ system level of organization Usually bilaterally symmetrical or evolved from bilateral ancestors Organized into several groups based on the presence or absence of body cavity and for those that posses one, the kind of body cavity present. Body cavity- fluid filled space in which the internal organs can be suspended and separated from the body wall Slide 38 Body cavities are advantageous 1.Provide more room for organ development 2.Provide more surface area for diffusion of gases, nutrients, and waste into and out of organs 3.Provide area for storage 4.Often act as hydrostatic skeletons (supportive yet flexible) 5.Provide a vehicle for eliminating wastes and reproductive products from the body 6.Facilitate increase in body size Slide 39 What does acoelomate mean? No coelom Slide 40 Acoelomate a, without+ kilos, hollow Mesoderm relatively solid mass No cavity formed between ecto and endo These cells within mesoderm often called parenchymal cells Parenchymal cells not speciallized for a particular fnc. Slide 41 Whats a coelom? coelom= true body cavity Fluid-filled lined by mesoderm-derived epithelium Earthworm Slide 42 Acoelomates lack a true body cavity Solid body no cavity b/w the digestive tract and outer body wall Slide 43 Do these questions now Think about aceolomate bilateral animals: To what domain do they belong kingdom What phyla include these organisms What is bilateral symmetry, and why was it an important evolutionary advantage movie Slide 44 Acoelomate Bilateral Animals Consist of phyla: Phylum Platyhelminthes Phylum Nemertea Others Slide 45 Slide 46 Acoelomate Bilateral Animals Reproductive and osmoregulatory systems 1.Simplest organisms to have bilateral symmetry 2.Triploblastic 3.Lack a coelom 4.Organ-system level of organization 5.Cephalization 6.Elongated, without appendages Slide 47 Acoelomate Bilateral Animals Reproductive and osmoregulatory systems 1.Simplest organisms to have bilateral symmetry 2.Triploblastic 3.Lack a coelom 4.Organ-system level of organization 5.Cephalization 6.Elongated, without appendages Slide 48 Triploblastic Pseudocoelomate pseudes, false Body cavity not entirely lined by mesoderm No muscle or connective tissue associated with gut No mesodermal Slide 49 The Triploblastic Coelomate Pattern Coelom is a body cavity completely surrounded by mesoderm Peritoneum- mesodermal sheet that lines the inner body wall and serosa (outer covering of visceral organs) Having mesodermally derived tissue (muscle, connective tissue) enhances the function of all internal body systems. Slide 50 Figure 7.12 Slide 51 Slide 52