1. CHARACTERISTICS OF ANIMALS

2. Characteristics of Animals What characteristics do all animals share? Animals, which are members of the kingdom ANIMALIA, are: MulticellularMulticellular HeterotrophicHeterotrophic EukaryoticEukaryotic

3. Characteristics of Animals –Animals are all heterotrophs; they obtain nutrients and energy by eating other organisms. –Animals are also multicellular; their bodies are composed of many cells. –The cells that make up animal bodies are eukaryotic, containing a nucleus and membrane-bound organelles.

4. Types of Animals All animals can be divided into two types: -Invertebrates -Vertebrates (Chordates)

5. Invertebrates Invertebrates include all animals that lack a backbone, or vertebral column.

6. Invertebrates More than 95 percent of animal species are informally called invertebrates. Invertebrates include at least 33 phyla. Invertebrates include: sea stars, worms, jellyfishes, and insects. They range in size from dust mites to giant squid more than 20 meters long.

7. Vertebrates All chordates exhibit four characteristics during at least one stage of life: a dorsal, hollow nerve cord a notochord a tail that extends beyond the anus pharyngeal pouches.

8. Vertebrates Fewer than 5 percent of animal species are chordates.

9. Needs for Survival

10. What Animals Do to Survive Animals must reproduce Animals must maintain homeostasis by: responding to information obtaining and distributing oxygen and nutrients collecting and eliminating carbon dioxide and other wastes

11. Maintaining Homeostasis Often, homeostasis is maintained by feedback inhibition, or negative feedback, a system in which the product or result of a process limits the process itself. for example, if you get too cold, you shiver, using muscle activity to generate heat or if you get too hot, you sweat, which helps you lose heat

12. Responding to Information The nervous system gathers information using cells called receptors that respond to sound, light, chemicals, and other stimuli.

13. Responding to Information Some invertebrates have only a loose network of nerve cells, with no real center. Other invertebrates and most chordates have large numbers of nerve cells concentrated into a brain. A leech has 32 brains! But not the brains you think of…

14. Obtaining and Distributing Oxygen and Nutrients All animals must “breathe” to obtain oxygen. organ systems diffusion

15. Obtaining and Distributing Oxygen and Nutrients All animals must “eat” to obtain nutrients. Most animals have a digestive system that acquires food and breaks it down into forms cells can use.

16. Obtaining and Distributing Oxygen and Nutrients After acquiring oxygen and nutrients, animals must transport them to cells throughout their bodies by using some kind of circulatory system.

17. Obtaining and Distributing Oxygen and Nutrients Open Circulatory System – pump blood into a hemocoel with the blood diffusing back to the circulatory system between cells Hemocoel - cavity or series of spaces between the organs of most arthropods and mollusks through which the blood circulates Closed Circulatory System – blood is pumped by a heart through vessels, and does not normally fill body cavities.

18. Collecting and Eliminating CO2 and Other Wastes Animals’ metabolic processes generate carbon dioxide and other waste products, some of which contain nitrogen in the form of ammonia. Both carbon dioxide and ammonia are toxic in high concentrations and must be excreted, or eliminated from the body.

19. Reproducing Most animals reproduce sexually by producing haploid gametes.

20. Reproducing Many invertebrates and a few vertebrates can also reproduce asexually (1 parent). Asexual reproduction produces offspring that are genetically identical to the parent.

21. Reproducing Sexual reproduction (2 parents) helps create and maintain genetic diversity, which increases a species’ ability to evolve and adapt as its environment changes.

22. Reproducing Terms to know: Viviparous - Bringing forth live young that have developed inside the body of the parent Oviparous - P roducing young by means of eggs that are hatched after they have been laid by the parent Ovoviparous - Producing young by means of eggs that are hatched within the body of the parent

23. ANIMAL BODY PLANS and EVOLUTION

24. Features of Body Plans Features of animal body plans include: levels of organization body symmetry differentiation of germ layers formation of body cavities patterns of embryological development segmentation cephalization limb formation

25. Levels of Organization As the first cells of most animals develop, they differentiate into specialized cells that are organized into tissues. A tissue is a group of cells that perform a similar function.

26. Levels of Organization Tissues combine during growth and development to form organs and organ systems that carry out complex functions.

27. Body Symmetry The bodies of most animals exhibit some type of symmetry. Radial Bilateral Asymmetrical

28. Differentiation of Germ Layers During embryological development, the cells of most animal embryos differentiate into three layers called germ layers. Endoderm Mesoderm Ectoderm

29. Differentiation of Germ Layers Cells of the endoderm, or innermost germ layer, develop into the linings of the digestive tract and much of the respiratory system. Cells of the mesoderm, or middle layer, give rise to muscles and much of the circulatory, reproductive, and excretory organ systems. The ectoderm, or outermost layer, produces sense organs, nerves, and the outer layer of the skin.

30. Formation of a Body Cavity Most animals have some kind of body cavity—a fluid-filled space between the digestive tract and body wall. A body cavity provides a space in which internal organs can be suspended and room for those organs to grow.

31. Formation of a Body Cavity Most complex animal phyla have a true coelom, a body cavity that develops within the mesoderm and is completely lined with tissue derived from mesoderm.

32. Formation of a Body Cavity Some invertebrates have only a primitive jellylike layer between the ectoderm and endoderm. Other invertebrates lack a body cavity altogether, and are called acoelomates.

33. Formation of a Body Cavity Still other invertebrate groups have a pseudocoelom, which is only partially lined with mesoderm.

34. Patterns of Embryological Development Every animal that reproduces sexually begins life as a zygote, or fertilized egg. As the zygote begins to develop, it forms a blastula, a hollow ball of cells.

35. Patterns of Embryological Development As the blastula develops, it folds in on itself, forming an elongated structure with a tube that runs from one end to the other. This tube becomes the digestive tract.

36. Patterns of Embryological Development At first this digestive tract has only a single opening. However, an efficient digestive tract needs two openings.

37. Patterns of Embryological Development In phyla that are protostomes, the blastopore becomes the mouth. The anus forms from a second opening. Most invertebrates are protostomes.

38. Patterns of Embryological Development In deuterostomes, the blastopore becomes the anus, and the mouth is formed from a second opening that develops. Chordates and echinoderms are deuterostomes.

40. Segmentation: Repeating Parts As many bilaterally symmetrical animals develop, their bodies become divided into numerous repeated parts, or segments.

41. Cephalization: Getting a Head Animals with bilateral symmetry typically exhibit cephalization, the concentration of sense organs and nerve cells at their anterior end. The most successful animal groups, including arthropods and vertebrates, exhibit cephalization.

42. Limb Formation: Legs, Flippers, and Wings Segmented, bilaterally symmetrical animals typically have external appendages on both sides of the body.

43. Limb Formation: Legs, Flippers, and Wings These appendages vary from simple groups of bristles in some worms, to jointed legs in spiders, wings in dragonflies, and a wide range of limbs, including bird wings, dolphin flippers, and frog legs.

44. Body Plans The body plans of modern invertebrates and chordates suggest evolution from a common ancestor.