Opener Chapter 7

1. Opener Chapter 7 Chapter 7 Animal Classification, Phylogeny, and Organization

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

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

4. Genus begins with a Capital letter • Entire name italicized or underlined • Homo sapien or H. sapien

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)

6. Figure 7.2 (b)

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

8. Figure 7.2 (a)

9. Monera- bacteria and cyanobacteria are prokaryotic

10. Protista- single or colonies of eukaryotic cells (Ameoba, Paramecium)

11. Plantae- eukaryotic, multicellular, and photosynthtic. Have cell wall, and usually nonmotile

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

13. Animalia- eukaryotic and multicellular, usually feed by ingesting other organisms, cell lack cell walls, and usually motile

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

15. Pattern of Organization • Asymmetry – i.e. ameoba • Symmetry • Radial symmetry- tube coral pulp • Bilateral symmetry- insects

16. Figure 7.7 Asymmetry red encrusting sponge

17. Figure 7.8 Radial symmetry tube coral pulp

18. Part 2

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)

20. Directed movement evolved with anterior sense organscephalization Cephalization • specialization of sense organs in head end of animals

21. Bilateral Symmetry • Divided along sagittal plane into two mirror images • sagittal= divides bilateral organisms into right and left halves

22. Anterior= head end • Posterior= tail end • Dorsal= back side • Ventral= belly side

23. Symmetry, fig. 7.9 • Median= sagittal

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.

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

26. Ceno-zoic Meso-zoic Paleozoic Humans Land plants Origin of solar system and Earth Animals 4 1 Proterozoic Eon Archaean Eon Billions of years ago 2 3 Multicellular eukaryotes Prokaryotes Single-celled eukaryotes Figure 26.10 Atmospheric oxygen • The analogy of a clock • Can be used to place major events in the Earth’s history in the context of the geological record ~500 million years ago Algea fossils

27. (a) Two-cell stage (b) Later stage 150 m 200 m • 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

28. The Colonial Connection 10 m • The first multicellular organisms were colonies • Collections of autonomously replicating cells May Lead to Cell Specialization Figure 26.16

29. Organisms can have more than one tissue layer • Diploblastic- two layers

30. What about Tripoblastic – three layers?

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

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

33. Figure 7.10

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

35. Figure 7.11 Diploblastic Triploblastic Diploblastic or Triploblastic?

36. Triploblastic animal

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

38. Body cavities are advantageous • Provide more room for organ development • Provide more surface area for diffusion of gases, nutrients, and waste into and out of organs • Provide area for storage • Often act as hydrostatic skeletons (supportive yet flexible) • Provide a vehicle for eliminating wastes and reproductive products from the body • Facilitate increase in body size

39. What does acoelomate mean? No coelom

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.

41. What’s a coelom? Earthworm • coelom= • true body cavity • Fluid-filled • lined by mesoderm-derived epithelium

42. Acoelomates lack a true body cavity • Solid body • no cavity b/w the digestive tract and outer body wall

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

44. Acoelomate Bilateral Animals • Consist of phyla: • Phylum Platyhelminthes • Phylum Nemertea • Others…

46. Acoelomate Bilateral Animals Reproductive and osmoregulatory systems • Simplest organisms to have bilateral symmetry • Triploblastic • Lack a coelom • Organ-system level of organization • Cephalization • Elongated, without appendages

47. Acoelomate Bilateral Animals Reproductive and osmoregulatory systems • Simplest organisms to have bilateral symmetry • Triploblastic • Lack a coelom • Organ-system level of organization • Cephalization • Elongated, without appendages

48. Triploblastic Pseudocoelomate pseudes, false • Body cavity not entirely lined by mesoderm • No muscle or connective tissue associated with gut • No mesodermal

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.

50. Figure 7.12