1. Animal kingdom groups (phyla)

2. What is an animal? Heterotroph (consumer, not decomposer)
Multicellular
Eukaryote
No cell wall (unlike fungi, plants, and bacteria)
Specialized cells (unlike protists)

3. Evolution of complexity
Need: sense and chase down food source
Adaptation: nervous / motor systems
Need: break up food and absorb nutrients
Adaptation: digestive system
Need: deliver oxygen to all cells
Adaptation: circulatory / respiratory systems

4. Sponges

5. Sponges
O2 and food come in through diffusion
Filter feeds as an adult

6. Sponges Unique among animal groups – No symmetry in overall body plan
No tissues (complex organization of cells)

7. Sponge reproduction
Sexual – release sperm into water (external fertilization very common in aquatic animals)
Hermaphroditism – sponges have sperm AND eggs to increase the odds of reproduction
Offspring can swim to a new location
Asexual fragmentation also possible

8. Sponges
Simplest animals
Possible colonial protozoan ancestor

9. Cnidarians
Sea anemone
Jellyfish

10. Evolution of radial symmetry
Definiton – can cut in equal halves more than one way
Ex: letters “O”, “X”
Purpose – extending tentacles equally in all directions (increase food uptake)

11. Cnidarian Basic digestive system Also basic nervous system (nerve net)
O2 still enters by diffusion

12. Revolution #1 – active movement
Filter feeding will not be sufficient for larger animals
Filter feeding will not work on land or in air
2 major adaptations to help organisms sense and move in their environment

13. Adaptation #1) Body symmetry
Bilateral symmetry allows for development of brain region in a central location (head)
Bilateral symmetry  cephalization

14. Adaptation #2: Body cavity
Coelom is a space inside body (empty / fluid)
Two purposes in evolutionary history:
a) Short-term: something for muscles to
push against to move
b) Long-term: space for larger organs
Not present in all animals (some have lost over evolutionary time)

15. Revolution #1 – active movement
Cephalization = “command center” to coordinate senses and movement +
Coelom = support for muscle movement

16. Flatworms
Planarian – not parasitic
Tapeworm – parasitic

17. Trends in flatworms No coelom Why? Many are parasitic
O2 and sugar absorbed in host’s intestine

18. Tapeworm life cycle

19. Roundworms
hookworm -- parasitic

20. Trends in roundworms Semi-developed coelom (moves a bit more)
Can burrow through skin (walking around barefoot), also enters through contaminated food

21. Not a problem in U.S.

22. Why not? Food safety inspections Good sanitation
Medication widely available

23. Mollusks
Clam – 2 shells
Snail – 1 shell
Squid – no shell

24. These are all in the same group!?!
inside of a clam

25. Mollusk traits
Getting food – filter feeders (clams), grazers (snails), predators (slugs)
Getting O2 – gills in aquatic mollusks, primitive lung in snails
Open or closed circulatory system

26. Open vs. closed Open Closed No blood vessels Blood vessels
Blood surrounds body’s organs, delivers O2
Smaller animals
Closed
Blood vessels
Larger animals

27. Reproduction Hermaphrodites (both mollusks and segmented worms)
Aquatic – release sperm and eggs into water
Land – meet and swap sperm, fertilize eggs inside

28. Segmented worms
leech
earthworm

29. Segmented worms
Full coelom (full range of motion, complex organs inside)
O2 – Gets O2 directly from moist skin,
closed circulatory system with hearts to deliver
Food – blood (leeches), or dirt (earthworms)

30. Earthworms rule Swallow dirt, filter out food
Loosen soil, helps to aerate soil for plants
Also fertilizes plants with castings (poop)

31. Leeches rule Two chemicals in saliva to help it take blood from hosts
Anesthetic
Anti-coagulant

32. Revolution #2 - skeletons
Structural support for larger bodies (remember, no cell walls in animal cells)
Two varieties:
1) Exoskeleton – outside body (arthropods) 2) Endoskeleton – inside body (echinoderms,
chordates)

33. Arthropods Four main classes within this HUGE phylum: Arachnids
Crustaceans
Centipedes / millipedes
Insects

34. Arachnids
Black widow
Brown recluse

35. Arachnids
Chigger (flea)
Tick
Scorpion

36. Crustaceans
Crab
Lobster
Barnacles

37. Many-footed ones
Centipede
Millipede

38. Insects
Wasp
Fire ants
Grasshopper

39. Arthropod traits Exoskeleton
Coelomate (I will also stop writing this now)
Segments still (possible connection to segmented worms)
Exoskeleton

40. Exoskeleton NOT the same as mollusk shell
Functions: 1) protection, 2) prevent water loss on land (waxy layer)
Problems: Heavy, growth requires molting
Therefore: arthropods tend to be smaller

41. For respiration… System for collecting O2 (tracheal tubes / spiracles)
Open circulatory system

42. Complex nervous system
Sophisticated sensory / motor control
Compound eye of a fruit fly

43. Arthropod reproduction
Internal fertilization (mating) in land arthropods
External fertilization in sea arthropods

44. Echinoderms
sea urchin
sea star
sea cucumber

45. Echinoderm traits adults = radial symmetry (live on ocean floor)
larvae are bilaterally symmetric
endoskeleton

46. Echinoderm traits
Food – variety of diet (some eat clams, some eat algae, some filter feed)
Water vascular system (water instead of blood to carry O2)
Reproduction typical in water

47. Chordates

48. All chordates
Have notochord – precursor to vertebral spinal column (semirigid, filled with fluid)
Vertebrates replace this with a full spinal cord
Some chordates are invertebrates still

49. Invertebrate chordates
lancelet
tunicate

50. Endoskeleton advantage
Organisms can grow larger with skeleton inside