1. First Animals Soft bodies so trace fossils only Sponges Jelly fish
Worms
Late Proterozoic

2. Time Line of Animal Evolution
1st Fossil evidence of animals 570 mya = Proterozoic Eon
Massive adaptive radiation of animals called the Cambrian Explosion signaled the start of the Phanerozoic Eon
Cambrian Explosion due to
increased oxygen for aerobic respiration
more energy = larger more mobile animals
move into new areas and adapt

3. Phanerozoic begins with Cambrian Explosion

4. Evolution of Animals
Some type of Protist mutated to become multicellular
Multicellular organisms start as a single cell (zygote) and grow into organisms with groups of specialized cells performing different functions
All animals are multicellular

6. Proterospongia = Protist & common ancestor to all animals?

7. Proterospongia: Colonial, Unicellular Protists

8. Sponge collar cells

9. Phylum Porifera Sponges Only 3 types of cells Collar cells Amoebocytes
Epidermis cells
(protective outer layer of cells)
No tissues
Cells held together by jelly like substance
Skeleton make of proteins
Asymetrical

11. Origin of sponges

12. Sponges are sessile filter feaders

13. Intracellular digestion (like protists)
Collar cells take in food by endocytosis
Food digested in food vacuoles
Some food passed to amoebocytes
Amoebocytes carry food around sponge body. (circulaton)

14. All other Animals have True Tissues & symmetry

15. Phylum Cnidaria Have stinging cells = cnidocytes Have tentacles
First predators..First muscle-like cells (movement)
Radial symmetry = sit and wait predator
1st nervous system =
nerve net & eye spots

19. Digestion & Circulation
Have gastrovascular cavity for
digestion & circulation
1st extra cellular digestion
– cells lining GVC secrete digestive enzymes
Evolutionary advantage = can eat larger food
Cilia push digested food around the GVC
GVC branches into all tentacles: comes near all cells

20. Prey capture

22. Jellyfish Reproduction
Moon jellies
Hydra eating

23. All other animals have Bilateral symmetry

24. Flatworms had it FIRST!! Bilateral symmetry
Directional motion = 1st mobile predator
Cephalization – development of a head
Ganglia: bundle of nerve cells make up a pre-brain
Nerves concentrated at ‘head end’ since sensory cells were concentrated at that end
Sensory nerves formed bundles = ganglion
Eyespots detect light,
Auricles detect chemicals ‘smell’
2 nerve cords transmit info to rest of body
Flatworms had it FIRST!!

25. Evolution of Bilateral Symmetry https://vimeo.com/37282961

26. Flatworm primitive Traits
Central mouth and GVC
Motion with cilia

27. Free-living Flatworms = Class Turbellaria
Marine
Fresh-water

28. Flukes = Class Trematoda
Parasites of blood and liver

29. Swimmer’s Itch =Schistosoma

30. Tape Worms = Class Cestoda

31. Human Tape Worm Sources =Under cooked Prevention Beef (N. America)
Pork(S. America)
Fish (Asia)
Prevention
Cook your meat!!!

32. Bilateral symmetry terms
Dorsal :
Back
Ventral:
Belly
Anterior:
head
Posterior:
tail

33. Embryo Development All Animals can do Sexual Reproduction
All make eggs and sperm
All start out as a single celled zygote
ALL Zygotes grow into a hollow ball of cells called a
blastula
Blastula gets indented forming a
gastrula

34. ALL Gastrulas develop at least 2 tissue layers
endoderm and ectoderm (diploblastic)
Some develop 3 layers endo, ecto and mesoderm
(triploblastic)

35. All Animals more advanced that flatworms have a body cavity
Provides room for organs to develop
Body Cavities are called coeloms

36. Types of body cavity (coelom)
Acoelomate Pseudocoelomate Coelomate

37. Round Worms = Phylum Nematoda
1st Animal with a body cavity =pseudocoelom
Fake body cavity – just a space between layers.

38. Advantage to body cavity =
space to grow specialized organs

39. Nematodes https://www.youtube.com/watch?v=dYPF5dmT__o
First Animal with Alimentary Canal ….
one way digestive tract mouth  anus
Advantages….
Can eat second meal before the first is fully digested
Can specialize different segments of digestive tube =
more efficient

40. Rotifers

41. Gastrulation Formation of gastrula.
Indentation creates opening called blastopore
Blastopore either becomes mouth or anus
Protostome = blastopore becomes mouth
Deuterostome = blastopore becomes anus

42. Ascaris…………………………… One of the most common parasite of humans
Up to 64% of
people in some
S.eastern states
Eggs injested
on Vegetables
or from Soil

43. Heartworm Larva in Blood