Introduction to animals

1. Introduction to animals Introduction to Animals

2. Characteristics of Animals • All multicellular • Eukaryotes(cells with nucleus & organelles) • No cell wall • Ingestive heterotrophs (take in food and internally digest it)

3. Lions Feeding (Ingestion)

4. Support Systems • Have some type of skeletal support • Endoskeleton inside and made of cartilage &/or bone • Exoskeletons found in arthropods • Cover the outside of the body • Limit size • Must be molted making animal vulnerable to predators

5. Cicada Molting Exoskeleton

6. Movement • Animals such assponges may be sessile(attached & non-moving) • Animals that move very little are said to be sedentary (clam) • Animals that can move are motile • Have muscular tissue to provide energy for movement

7. SESSILE SEDENTARY Chiton Sponge MOTILE Cheetah

8. Reproduction in Animals • All animals are capable of sexual reproduction

9. Leeches Exchange Sperm During Mating leech Mating

10. Female Beetles Mating Young Courtship Male Mating and Mating Behaviors

11. Molecule or compound Atom Organelle Levels of Organization CELL Life begins Tissue Organ Organ system Organism

12. Levels of Organization • animals show these levels – cell, tissue, organ, and organ system • Sponges are the ONLY animals that have just the cellular level • Cells may specialize (take own different shapes and functions)

13. Surfaces (Most Animals) DORSAL Back or upper surface POSTERIOR Tail or hind end ANTERIOR Head or Front VENTRAL Belly or lower surface

14. Body Symmetry • Symmetry is the arrangement of body parts around a central plane or axis • Asymmetry- no symmetry (sponges)

15. Body Symmetry • Radial symmetry occurs when body parts are arranged around a central point • Most animals with radial symmetry are sessile (attached) or sedentary (move very little)

17. Body Symmetry • Bilateral symmetry is whenanimals can be divided into equal halves • Organisms will have right and left sides mirror imagesof each other • Most complex type of symmetry

18. Body Symmetry • Animals with bilateral symmetry are usually motile • Animals have an anterior and posterior ends • Show cephalization (concentration of sensory organs on the head or anterior end)

20. Body Symmetry

21. Tissues

22. Tissue Development • Zygote (fertilized egg) undergoes rapid cell divisions called cleavage • Forms a hollow ball of cells called the blastula

23. BlastulaA hollow ball of cells • The blastocoel is the center cavity of the blastula with 1 germ layer (blastoderm)

24. Germ Layers • Form tissues, organs, & systems • NOT present in sponges • Ectoderm (outer) – forms skin, nerves, sense organs • Endoderm (inner) – forms digestive, respiratory • Mesoderm (middle) – forms muscles, excretory, bones, circulatory

25. Body Layers • Sponges have NO tissues or organs, only specialized cells • Cnidarians like jellyfish & coral have only two body layers & one body opening (mouth/anus) into gastrovascular cavity • Cnidarians have outer epidermis & inner gastrodermis with jelly-like mesoglea between the layers

27. Body Cavities

28. Coelom - Body Cavity • Internal body cavity fully lined with mesoderm(coelomates) • Body organs suspended in this cavity • Eucoelomates – “true” coelom vertebrates & some invertebrates

29. Coelom - Body Cavity • Acoelomate animals have solid bodies filled with cells • Acoelomate animals include sponges, cnidarians, & flatworms

30. Coelom - Body Cavity • Pseudocoelomate animals (roundworms) have a functional body cavity NOT fully lined with mesoderm (ex. nematodes)

31. Images from: http://www.geocities.com/animalbio/biology/DIGESTIO.gif Digestive Systems Only one opening (two way): FOOD IN and WASTE OUT through same opening

32. Digestive Systems • Animals with a two openings (one- way digestive system have a mouth and an anus • Food enters the mouth, continues in one direction through the digestive tract, and wastes leave through the anus • Most efficient • Includes annelids, arthropods, & vertebrates

33. One-Way Digestion Mouth anus

34. Circulatory Systems • Transports oxygen & nutrients to cells • Carries away wastes & carbon dioxide from cells • Sponges, cnidarians, & flatworms do NOT have circulatory systems

35. Circulatory Systems • In closed circulation, blood remains inside blood vessels until it reaches cells(annelids & vertebrates) • In open circulation, blood is pumped out of blood vessels to bathe tissues in the body cavity (arthropods & mollusks)

36. Closed Circulation Open Circulation

37. Invertebrate groups

39. Characteristics of Invertebrates • Simplest animals • Contain the greatest number of different species • Most are aquatic (found in water) • Do NOT have a backbone • Includes sponges, cnidarians, flatworms, roundworms, annelids, mollusks, arthropods, and echinoderms

40. Sponge - Porifera Osculum of Sponge

41. More Cnidarians Brain Coral Red jellyfish

42. Flatworms - Platyhelminthes Marine Flatworm Planarian

43. Roundworms (Nematoda) and Segmented Worms (Annelida) Nematode Leech (segmented worm)

44. Mollusca (With and Without Shells) snail scallop octopus nudibranch nautilus

45. Arthropoda (insects, spiders, crustaceans, horseshoe crab) spider crayfish Horseshoe crab Dung beetle

46. Echinoderms Sea fan (crinoid) starfish Brittle star Sand dollar Sea cucumber

48. Vertebrata • More complex animals • have a backbone made up of individual bones called vertebrae • From simplest to most complex, the phylum includes: fish, amphibians, reptiles, birds, and mammals

49. Vertebrata • Vertebrates have endoskeletons (internal) • Some vertebrates have skeletons of cartilage (sharks, rays, and skates) • Other vertebrates have skeletons of bone and cartilage (reptiles, birds, & mammals)

50. Bone & Cartilage in Fetus