1. Do First
Grab the introductions to animals worksheet and the invertebrate packet

2. Introduction to Animals
Chapter 26

3. What characteristics do all animals share?
They are multicellular
Their cells are eukaryotic and lack walls
They are heterotrophic by ingestion
They mainly reproduce sexually
They are able to move

4. How are Animals Classified?
BY THE LACK OR PRESENCE OF TRUE TISSUES
True tissues are groups of similar cells that perform a common function
Ex: Muscle Tissue

5. How are Animals Classified?
BY BODY SYMMETRY
Asymmetry is the lack of body symmetry
Radial symmetry is when body parts are arranged in a circle around a central axis
Bilateral symmetry is when the body can be divided equally along one plane

6. How are Animals Classified?
BY THE PRESENSE AND TYPE OF INTERNAL BODY CAVITY
1.) Acoelomate
No body cavity
2.) Pseudocoelomate
No true body cavity
3.) Coelomate
True body cavity
Fluid-filled space b/t body wall and gut

8. How are Animals Classified?
WHETHER OR NOT THE BODY IS ASSEMBLED IN SEGMENTS

9. How are Animals Classified?
BY THE PRESENSE OR ABSENCE OF JOINTED APPENDAGES
Joints permit powerful movement and aid in locomotion.
Allow animals to perform complex movements

10. How are Animals Classified?
WHETHER THEY DEVELOP IN A DEUTEROSTOME OR PROTOSTOME PATTERN
In protostomes, the mouth is formed first, then the anus
In deuterostomes, the anus is formed first, then the mouth

11. Notes 1. Take out your note packet
2. Think to yourself: What is one way that animals are classified?

12. Phylum Porifera

13. Members
Sponges – the simplest animals

14. Body Structure Asymmetrical No tissues or organs
Openings called pores (or ostia) cover body wall
Cells are suspended in jelly like layer called mesoglea
“Skeleton” made of spicules

15. Feeding
Sponges are filter feeders – they filter plankton from sea water
Water enters through ostia and waste exits through oscula
Ostia

16. Movement
Adult sponges are sessile – they are attached to the ocean floor and cannot move
Larvae can swim

17. Reproduction Asexual: Budding and/or fragmentation Sexual:
Sperm is released and fertilizes egg that is retained in sponge
Free swimming larva swims to another location where it remains and develops into a new adult

18. Unique Characteristics
Spicules
Asymmetry
Collar Cells

19. Phylum Cnidaria

20. Members
Hydras; Corals; Jellyfish; Sea anemones

21. Body Structure Radial Symmetry
Body composed of outside (ectoderm) & inside (endoderm) layers
No body cavity
Jelly fish have hydrostatic skeleton (water filled cavity) that is under pressure

22. Feeding
They are predators – they capture prey w/ stinging tentacles using cnidocytes
Gastrovascular cavity allows for 2 way feeding

23. Movement Cnidarians have two body forms
Medusa: Free floating; mushroom shaped
Polyp: Attached to rock; pipe shaped

24. Reproduction Asexual: by budding Sexual: Release gametes into water
After fertilization, the larva is free-swimming
The larva then develops into an adult

25. Unique Characteristics
Cnidocytes (stinging cells)
Nematocyst
Cnidocyte

26. Phylum Platyhelminthes

27. Members
Flatworms:
Tapeworms, flukes, planarians

28. Body Structure Bilateral Symmetry
Anterior/posterior
Dorsal/ventral
Sense organs grouped at the anterior end
Better to sense where you are going than where you have been (foreshadows brain)
Three tissue layers (ecto, meso, endoderm) – no coelom
Ocelli function as eyes

29. Feeding One opening allows for 2 way digestion
The opening is called the pharynx and is found on the ventral side in the middle

30. Movement Muscles found in mesoderm aid in movement
Bilateral symmetry, nerves at one end (ganglion), and ocelli allow for movement in forward direction

31. Reproduction Asexual: Regeneration Sexual: Many are hermaphroditic
This characteristic is common in parasites… why?

32. Unique Characteristics
None

33. Phylum Nematoda

34. Members Roundworms Ex: Hookworms; pinworms; heartworms
Elephantiatis is caused by a type of roundworm blocking the lymphatic system, causing limbs to swell

35. Body Structure Bilateral Symmetry Not Segmented Three tissue layers
Pseudocoelom
Nerve cells and sensory cells located towards head

36. Feeding
The digestive system has separate openings for feeding and waste elimination (one-way!) Not very differentiated
This allows them to acquire more food, which increases their activity level

37. Movement
Long layers of muscle that pull against the body’s outer covering and the pseudocoelom whips the worm’s body from side to side
Better coordinated than acoelomates

38. Reproduction
Usually reproduce sexually

39. Unique Characteristics
None

40. Phylum Mollusca

41. Members
Snails, slugs, octopus, squid, oysters, mussels, and others

42. Body Structure Bilateral Symmetry
Three tissue layers with TRUE COELOM (reduced in size)
Isolates the internal organs from body-wall movements, allowing for increased activity level and increased organ complexity
Have soft bodies (some have shells)
Not segmented
Organ systems for excretion, circulation, respiration, digestion, reproduction

43. Feeding
Most have a radula which scrapes food off of rocks or plant matter
Food is digested in the stomach and intestine of the one way digestive tract
Wastes are passed out of the anus

44. Movement Widely varied Some glide along surface (ex: snails)
Some shoot water out of a siphon to propel themselves; or, creep along using suction cups (octopus)
Some are mostly sessile, but can open and close their shells quickly to propel themselves (mussels)

45. Reproduction Sexes are usually separate
Fertilization occurs externally in most aquatic mollusks
Fertilization occurs internally in most terrestrial mollusks and octopuses
Larva is called trocophore

46. Unique Characteristics
Radula – used to scrape food off of surfaces

47. Phylum Annelida

48. Members
Segmented worms: Earthworms, marine worms, & leeches

49. Body Structure Bilaterally Symmetrical
Have segmentation: Repeated sections of body that contain complex sets of body structures
Three tissue layers
Coelom
Organ systems for excretion, digestion, circulation, sensing, etc…

50. Feeding Separate openings for mouth and anus
Eat organic waste material
They excrete digested material (called castings) that helps maintain nutrient-rich soil
Leeches are sanguivorous - they feed as blood sucking parasites on preferred hosts.

51. Movement
Annelids use their hydrostatic skeleton to move from one place to another
Their characteristic crawling motion is due to different sets of muscles lengthening and shortening at different times
Peristalsis Video

52. Reproduction Asexual by fragmentation Sexual Some are hermaphroditic
Some have separate sexes

53. Unique Characteristics
None

54. Phylum Arthropoda
Jointed
Feet

55. Members
Crustaceans, Spiders, & Insects

56. Body Structure Bilaterally Symmetrical Three tissue layers Coelom
Segmented
Covered with an exoskeleton made of chitin
Jointed & waterproof
Well developed brain and sense organs

57. Feeding
Arthropods have a completely differentiated digestive system (each part as a special job)
They can be carnivores, herbivores, detritus feeders, filter feeders, and parasites
Typically, paired appendages around the mouth are used for collecting and handling food and are usually specialized according to their diet

58. Movement Joints permit powerful movement and aid in locomotion
Muscles in arthropods are attached to the endoskeleton across joints
Different groups of arthropods are adapted for movement on land, water, & in the sky

59. Reproduction Sexes are usually separate
Fertilization usually occurs externally
In many species, such as spiders, the young look like miniature adults
The young of other arthropod species have little or no physical resemblance to adults and go through metamorphosis

60. Unique Characteristics
Jointed exoskeleton made of chitin

61. Phylum Echinodermata
Spiny
Skinned

62. Members
Sea urchins, brittle stars and sea cucumbers

63. Body Structure Have an endoskeleton made of calcium
Bilateral symmetry as larvae; radial symmetry as adults
Nervous system called “nerve ring” allows them to perform complex movements
Have a coelom (body cavity) that functions as a simple circulatory and respiratory systems

64. Feeding One-way digestion (mouth on ventral side; anus on dorsal side)
Echinoderms can eat by ejecting their stomachs out of their mouths onto a food source and “slurping up” the food source once it has been digested by stomach enzymes
Sometimes, their food sources are harder to get to – they can use their tube feet to suction open a prey item before digesting it

65. Movement
Echinoderms have hundreds of tube feet on their ventral side that act as little “suckers”
The tube feet allow them to crawl along surfaces

66. Reproduction Some are hermaphroditic; some have separate sexes
Asexually: Fragmentation (if an arm breaks off, it can develop into a whole new organism)
Sexually: Females and males release their gametes (eggs and sperm) into water, where fertilization occurs

67. Unique Characteristics
Nerve Ring
Tube feet