1. 9-1 CHAPTER 9 Architectural Pattern of an Animal

2. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-2 New Designs for Living Zoologists recognize 34 major phyla of living multicellular animals Zoologists recognize 34 major phyla of living multicellular animals Survivors of around 100 phyla that appeared 600 million years ago during Cambrian explosion Survivors of around 100 phyla that appeared 600 million years ago during Cambrian explosion Most important evolutionary event in geological history of life Most important evolutionary event in geological history of life Virtually all major body plans evolved Virtually all major body plans evolved Major body plans Major body plans Result of extensive selection Result of extensive selection Are limiting determinant of future adaptational variants Are limiting determinant of future adaptational variants

3. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Grades of Organization: Grades of Organization: Unicellular Multicellular Tissue Tissue-Organ Organ System Tissue-Organ Organ System 9-3

4. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Table 9.1

5. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-5 Hierarchical Organization of Animal Complexity Grades of Organization Grades of Organization Unicellular protozoans Unicellular protozoans Simplest eukaryotic organisms Simplest eukaryotic organisms Protoplasmic Grade of Organization Protoplasmic Grade of Organization Perform all basic functions with confines of single cell Perform all basic functions with confines of single cell

6. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-6 Metazoa Metazoa Multicellular animals Multicellular animals Cells are specialized parts of whole organism Cells are specialized parts of whole organism Cannot live alone Cannot live alone Cellular Grade of Organization Cellular Grade of Organization Simplest metazoans Simplest metazoans Cells demonstrate division of labor but are not strongly associated to perform a specific collective function Cells demonstrate division of labor but are not strongly associated to perform a specific collective function Hierarchical Organization of Animal Complexity

7. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-7 Tissue Grade of Organization Tissue Grade of Organization Cells grouped together Cells grouped together Perform common function as a unit (tissue) Perform common function as a unit (tissue) Tissue-Organ Grade of Organization (Eumetazoans) Tissue-Organ Grade of Organization (Eumetazoans) Tissues assembled into larger functional units called organs Tissues assembled into larger functional units called organs Chief functional cells of an organ- Parenchyma Chief functional cells of an organ- Parenchyma Supportive tissues of an organ- Stroma Supportive tissues of an organ- Stroma Hierarchical Organization of Animal Complexity

8. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-8 Organ-System Grade of Organization Organ-System Grade of Organization Organs work together to perform a common function Organs work together to perform a common function Highest level of organization Highest level of organization Associated with most animal phyla Associated with most animal phyla Hierarchical Organization of Animal Complexity

9. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Symmetry 9-9

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11. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-11 Animal Body Plans Animal Symmetry Animal Symmetry Symmetry Symmetry Correspondence of size and shape of parts on opposite sides of a median plane (a vertical plane that divides an organism in to symmetrical halves.) Correspondence of size and shape of parts on opposite sides of a median plane (a vertical plane that divides an organism in to symmetrical halves.) Spherical symmetry Any plane passing through center divides body into mirrored halves Any plane passing through center divides body into mirrored halves Best suited for floating and rolling Best suited for floating and rolling Found among some unicellular forms Found among some unicellular forms Rare in animals Rare in animals

12. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1. Spherical symmetry Any plane passing through center divides body into mirrored halves Any plane passing through center divides body into mirrored halves Best suited for floating and rolling Best suited for floating and rolling Found among some unicellular forms Found among some unicellular forms Rare in animals Rare in animals 9-12

13. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-13 2. Radial symmetry Body divided into similar halves by more than 2 planes passing through longitudinal axis Body divided into similar halves by more than 2 planes passing through longitudinal axis a. Biradial symmetry Variant form radial symmetry Variant form radial symmetry Have part that is single or paired rather than radial Have part that is single or paired rather than radial Only 2 planes passing through longitudinal axis produces mirrored halves Only 2 planes passing through longitudinal axis produces mirrored halves Usually sessile, freely floating, or weakly swimming animals Usually sessile, freely floating, or weakly swimming animals No anterior or posterior end No anterior or posterior end Can interact with environment in all directions Can interact with environment in all directions Animal Body Plans

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15. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-15 3. Bilateral Symmetry Organism can be divided along a sagittal plane into two mirror portions Organism can be divided along a sagittal plane into two mirror portions Right and left halves Right and left halves Much better fitted for directional (forward) movement Much better fitted for directional (forward) movement Associated with cephalization Associated with cephalization Differentiation of a head region with concentration of nervous tissue and sense organs Differentiation of a head region with concentration of nervous tissue and sense organs Advantageous to an animal moving through its environment head first Advantageous to an animal moving through its environment head first Always accompanied by differentiation along an anteroposterior axis Always accompanied by differentiation along an anteroposterior axis Animal Body Plans

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17. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-17 Regions of bilaterally symmetrical animals Regions of bilaterally symmetrical animals Anterior Anterior Head end Head end Posterior Posterior Tail end Tail end Dorsal Dorsal Back or upper side Back or upper side Ventral Ventral Front or belly side Front or belly side Medial Medial Midline of body Midline of body Lateral Lateral Sides Sides Animal Body Plans

18. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-18 Distal Distal Parts farther from the middle of body Parts farther from the middle of body Proximal Proximal Parts are nearer the middle of body Parts are nearer the middle of body Animal Body Plans

19. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Frontal plane (coronal plane) Frontal plane (coronal plane) Divides bilateral body into dorsal and ventral halves Divides bilateral body into dorsal and ventral halves Sagittal plane Sagittal plane Divides body into right and left pieces Divides body into right and left pieces Transverse plane (cross section) Transverse plane (cross section) Divides body into anterior and posterior portions Divides body into anterior and posterior portions 9-19

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21. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fig. 9.3

22. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Body Cavity 9-22

23. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-23 Body Cavities and Germ Layers Body cavity Body cavity Sponges Sponges Acoelomate: no body cavity Acoelomate: no body cavity In sponges In sponges After blastula formation, cells reorganize to form adult body After blastula formation, cells reorganize to form adult body Blastula has no external opening Blastula has no external opening No gut forms No gut forms

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25. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-25 Other animal phyla Other animal phyla Development proceeds from blastula to gastrula Development proceeds from blastula to gastrula Blastula is a mass of cells that has undergone numerous cleavages after the zygote Blastula is a mass of cells that has undergone numerous cleavages after the zygote Gastrula is what forms after the blastula when invagination begins to form Gastrula is what forms after the blastula when invagination begins to form Invagination of surface cells form the archenteron or primitive gut Invagination of surface cells form the archenteron or primitive gut Opening to archenteron is the blastocoel Opening to archenteron is the blastocoel Becomes the mouth or the anus Becomes the mouth or the anus Gut is lined by endoderm Gut is lined by endoderm Outer layer of cells is ectoderm Outer layer of cells is ectoderm Body Cavities and Germ Layers

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27. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-27 Embryo now has 2 cavities Gut and blastocoel Gut and blastocoel Blastocoel persists in some animals Blastocoel persists in some animals In others, becomes filled with a 3 rd germ layer, mesoderm In others, becomes filled with a 3 rd germ layer, mesoderm Cells forming mesoderm Cells forming mesoderm Derived from endoderm Derived from endoderm 2 mechanisms of formation 2 mechanisms of formation Body Cavities and Germ Layers

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29. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. The majority of coelomate invertebrates develop as protostomes ("first mouth") in which the oral end of the animal develops from the first developmental opening, the blastopore. The majority of coelomate invertebrates develop as protostomes ("first mouth") in which the oral end of the animal develops from the first developmental opening, the blastopore. In the deuterostomes ("second mouth": cf. Deuteronomy, "second book of the law"), including Echinodermata and the ancestors of the Chordata, the oral end of the animal develops from a second opening on the dorsal surface of the animal; the blastopore becomes the anus. In the deuterostomes ("second mouth": cf. Deuteronomy, "second book of the law"), including Echinodermata and the ancestors of the Chordata, the oral end of the animal develops from a second opening on the dorsal surface of the animal; the blastopore becomes the anus.Chordata 9-29

30. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Protosomes vs Deuterostomes 9-30

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33. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Protosomes 9-33

34. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-34 In Protostomes In Protostomes Mesoderm forms as endodermal cells near blastopore migrate into the blastocoel Mesoderm forms as endodermal cells near blastopore migrate into the blastocoel Three body plans are possible Three body plans are possible Acoelomate plan Acoelomate plan Mesodermal cells completely fill the blastocoel Mesodermal cells completely fill the blastocoel Gut is only body cavity Gut is only body cavity Body Cavities and Germ Layers

35. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-35 Pseudocoelomate plan Pseudocoelomate plan Mesodermal cells line the outer edge of the blastocoel Mesodermal cells line the outer edge of the blastocoel 2 body cavities formed 2 body cavities formed Persistent blastocoel (pseudocoelom) and a gut cavity Persistent blastocoel (pseudocoelom) and a gut cavity Pseudocoelom is a false body cavity (only partially lined with mesoderm) Pseudocoelom is a false body cavity (only partially lined with mesoderm) Body Cavities and Germ Layers

36. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-36 Schizocoelous plan Schizocoelous plan Mesodermal cells fill blastocoel Mesodermal cells fill blastocoel Mesoderm splits Mesoderm splits The space is called a coelom The space is called a coelom True body cavity (completely lined by mesoderm) True body cavity (completely lined by mesoderm) 2 body cavities formed 2 body cavities formed Gut and coelom Gut and coelom Body Cavities and Germ Layers

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38. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Deuterostomes 9-38

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40. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-40 In Deuterostomes In Deuterostomes Mesoderm forms by an enterocoelous plan Mesoderm forms by an enterocoelous plan Cells from central gut lining form pouches Cells from central gut lining form pouches Pouches expand into blastocoel Pouches expand into blastocoel Wall forms mesodermal ring Wall forms mesodermal ring Pouches enclose a space, coleom Pouches enclose a space, coleom Pouches pinch off from gut lining Pouches pinch off from gut lining 2 body cavities form 2 body cavities form Gut and coelom Gut and coelom Body Cavities and Germ Layers

41. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fig. 9.3b

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43. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Diploblasts and Triploblasts Deuterostomes 9-43

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46. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-46 Developmental Origins in Triploblasts Body Plans Triploblastic animals follow one of several major developmental pathways Triploblastic animals follow one of several major developmental pathways Most common pathways are by spiral or radial cleavage Most common pathways are by spiral or radial cleavage Radial cleavage Radial cleavage Typically accompanied by 3 traits Typically accompanied by 3 traits Blastopore becomes the anus and new opening becomes the mouth Blastopore becomes the anus and new opening becomes the mouth Coelom formation is by enterocoely Coelom formation is by enterocoely Cleavage is regulative Cleavage is regulative Animals with these features called deuterostomes Animals with these features called deuterostomes

47. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-47 Spiral cleavage Spiral cleavage Produces embryos whose developmental pattern contrast with those of deuterostomes Produces embryos whose developmental pattern contrast with those of deuterostomes Blastopore becomes the mouth Blastopore becomes the mouth Cleavage is mosaic Cleavage is mosaic Mesoderm forms from 4d cell Mesoderm forms from 4d cell May be acoelomate, pseudocoelomate, or coelomate (schizocoely) May be acoelomate, pseudocoelomate, or coelomate (schizocoely) Animals with these features are called lophotrochozoan protostomes Animals with these features are called lophotrochozoan protostomes Developmental Origins in Triploblasts Body Plans

48. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-48 Ecdysozoan protostomes Ecdysozoan protostomes Exhibit a range of cleavage patterns including spiral cleavage Exhibit a range of cleavage patterns including spiral cleavage Coelomate or psuedocoelomate Coelomate or psuedocoelomate Few diploblasts and triploblasts form blind gut Few diploblasts and triploblasts form blind gut Same opening for entrance of food and exit of wastes Same opening for entrance of food and exit of wastes Most form a complete gut Most form a complete gut Allows for one-way flow of food from mouth to anus Allows for one-way flow of food from mouth to anus Tube-within-a-tube design Tube-within-a-tube design Developmental Origins in Triploblasts Body Plans

49. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-49 A Complete Gut Design and Segmentation Metamerism (Segmentation) Metamerism (Segmentation) Serial repetition of similar body segments along longitudinal axis of body Serial repetition of similar body segments along longitudinal axis of body Each segment is a metamere or somite Each segment is a metamere or somite Permits greater body mobility and complexity of structure and function Permits greater body mobility and complexity of structure and function Annelids, Arthropods, Chordates Annelids, Arthropods, Chordates

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51. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-51 Cellular Components: Tissues Cellular Components: Tissues Histology is the study of types of tissues Histology is the study of types of tissues Four major types of tissues form during embryonic development Four major types of tissues form during embryonic development Epithelial Tissue Epithelial Tissue Connective Tissue Connective Tissue Muscular Tissue Muscular Tissue Nervous Tissue Nervous Tissue Components of Metazoan Bodies

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53. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fig. 9.7

54. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-54 Epithelial Tissue Epithelial Tissue Sheet of cells that covers an internal or external surface Sheet of cells that covers an internal or external surface Avascular Avascular Function Function Protection Protection Absorption Absorption Secretion Secretion Components of Metazoan Bodies

55. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-55 Simple epithelia Simple epithelia Single layer of cells Single layer of cells Found in all metazoa Found in all metazoa Stratified epithelia Stratified epithelia 2 or more cell layers 2 or more cell layers Restricted to vertebrates Restricted to vertebrates Separated from underlying tissues by a basement membrane Separated from underlying tissues by a basement membrane Components of Metazoan Bodies

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58. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-58 Connective Tissue Connective Tissue Widespread in body Widespread in body Contains relatively few cells, many fibers, and a ground substance or matrix Contains relatively few cells, many fibers, and a ground substance or matrix 2 types of connective tissue proper In vertebrates 2 types of connective tissue proper In vertebrates Loose connective tissue Loose connective tissue Anchors blood vessels, nerves, and body organs Anchors blood vessels, nerves, and body organs Consists of fibroblasts that synthesize fibers, ground substance and wandering macrophages Consists of fibroblasts that synthesize fibers, ground substance and wandering macrophages Dense connective tissues Dense connective tissues Characterized by densely packed fibers and little matrix Characterized by densely packed fibers and little matrix Connective tissue also includes blood, lymph, cartilage, and bone Connective tissue also includes blood, lymph, cartilage, and bone Components of Metazoan Bodies

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61. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-61 Muscular Tissue Muscular Tissue Most abundant tissue in most animals Most abundant tissue in most animals Originates from mesoderm Originates from mesoderm Muscle cell called a muscle fiber Muscle cell called a muscle fiber Specialized for contraction Specialized for contraction 3 types 3 types Skeletal Skeletal Striated, unbranched, multinuclei, and voluntary Striated, unbranched, multinuclei, and voluntary Cardiac Cardiac Striated, branched, 1-2 nuclei, involuntary Striated, branched, 1-2 nuclei, involuntary Smooth Smooth No striations, unbranched, 1 nucleus, involuntary No striations, unbranched, 1 nucleus, involuntary Components of Metazoan Bodies

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64. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-64 Nervous Tissue Nervous Tissue Specialized to receive stimuli and conduct impulses from one region to another Specialized to receive stimuli and conduct impulses from one region to another 2 basic cell types 2 basic cell types Neurons Neurons Structural and functional unit of nervous system Structural and functional unit of nervous system Neuroglia Neuroglia Insulate and support neurons. Insulate and support neurons. Components of Metazoan Bodies

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68. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-68 Complexity and Body Size More complex grades of metazoan organization More complex grades of metazoan organization Permit and promote evolution of large body size Permit and promote evolution of large body size As body increases in size As body increases in size The surface area increase much slower than the body volume The surface area increase much slower than the body volume

69. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-69 A large animal has less surface area compared to its volume than does a smaller animal A large animal has less surface area compared to its volume than does a smaller animal May be inadequate for respiration and nutrition by cells located deep within its body May be inadequate for respiration and nutrition by cells located deep within its body Flattening or infolding the body increases surface area, as in flatworms Flattening or infolding the body increases surface area, as in flatworms Most animals developed internal transports systems to shuttle nutrients, gases and waste products, as they became larger Most animals developed internal transports systems to shuttle nutrients, gases and waste products, as they became larger Complexity and Body Size

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71. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-71 Benefits of Being Large Benefits of Being Large Buffers against environmental fluctuations Buffers against environmental fluctuations Provides protection against predators and promotes offensive tactics Provides protection against predators and promotes offensive tactics Cost of maintaining body temperature is less per gram of body weight than in small animals Cost of maintaining body temperature is less per gram of body weight than in small animals Energy costs of moving a gram of body weight over a given distance less for larger animals Energy costs of moving a gram of body weight over a given distance less for larger animals Complexity and Body Size