1. General Zoology Unit Five

2. Hemichordata Eukaryotic, eumetazoans, deuterostomes
Triploblastic, eucoelomates
Bilaterally symmetrical (cephalization)
Worm like body divided into three segments
Complete digestive system
Closed circulatory system with dorsal heart
Respiration through gill slits
Sexual reproduction – dioecious, external fertilizers with metamorphosis

3. Phylum Hemichordata

4. Chordate Characteristics

5. Chordate Taxonomy Kingdom - Animalia Phylum - Chordata
Subphylum - Urochordata (tunicates)
Subphylum - Cephalochordata (lancelets)
Ex. Branchiostoma
Subphylum - Vertebrata
Superclass - Agnatha
Class - Myxini (hagfish)
Class - Cephalaspidomorphi (lampreys)

6. Chordate Taxonomy Kingdom - Animalia Phylum - Chordata
Subphylum - Vertebrata
Superclass - Gnathostomata
Class - Chondrichthyes (sharks, skates, rays)
Class - Actinopterygii (ray finned bony fish)
Class - Sarcopterygii (lobe finned bony fish)
Class - Amphibia
Class - Reptilia
Class - Aves
Class - Mammalia

7. Subphylum Urochordata

8. Subphylum Urochordata

9. Subphylum Cephalochordata

10. Garstang’s Hypothesis of Vertebrate Evolution

11. Developmental Definitions
Paedomorphosis - the retention of larval traits in the adult body
Neotony - a process in which the growth rate is slowed to the extent that sexual maturity is reached before the ancestral adult form is obtained

12. Developmental Definitions
Progenesis - the precocious maturation of the gonads in a juvenile body that stops growing and never attains the adult body form
Post-displacement - a delay of the onset of a developmental process relative to sexual maturity, so that the ancestral adult form is not attained before reproductive maturity

13. Garstang’s Hypothesis of Vertebrate Evolution

14. Vertebrate Ancestry

15. Fish Taxonomy Kingdom - Animalia Phylum - Chordata
Subphylum - Vertebrata
Superclass - Agnatha
Class - Myxini (hagfish)
Ex. Myxine
Class - Cephalaspidomorphi (lampreys)
Ex. Petromyzon

16. Fish Taxonomy Kingdom - Animalia Phylum - Chordata
Subphylum - Vertebrata
Superclass - Gnathostomata
Class - Chondrichthyes (sharks, skates, rays)
Subclass - Elasmobranchii (sharks, skates, rays)
Ex. Squalus, Raja
Subclass - Holocephali (chimeras or ratfish)
Ex. Chimera

17. Fish Taxonomy Kingdom - Animalia Phylum - Chordata
Subphylum - Vertebrata
Superclass - Gnathostomata
Class - Actinopterygii (ray finned bony fish)
Ex. Perca, Amia, Polyodon
Class - Sarcopterygii (lobe finned bony fish
Ex. Latimeria

18. Subphylum Vertebrata All five chordate hallmark characteristics
Endoskeleton of cartilage or bone
Complete digestive tract
Closed circulatory system with a ventral heart
Complex nervous system with a brain, dorsal nerve cord and advanced sense organs
Excretion carried out by paired kidneys
Most have two pairs of appendages

19. Superclass Agnatha All members have the vertebrate characteristics
All are jawless
All are elongated and eel shaped
None have paired appendages
Scales are absent
Complete digestive system without a stomach
The notochord is persistent into adulthood

20. Superclass Agnatha

21. Superclass Agnatha

22. Superclass Gnathostomata
All members have the vertebrate characteristics
All members have a jaw
All have or have had paired appendages
All have an endoskeleton of cartilage or bone

23. Class Chondrichthyes

24. Class Chondrichthyes

25. Class Chondrichthyes

26. Class Chondrichthyes

27. Class Actinopterygii

28. Class Actinopterygii

29. Class Actinopterygii

30. Class Sarcopterygii

31. Class Sarcopterygii

32. Osmoregulation in Fish

33. Respiration in Fish

34. Respiration in Fish

35. Respiration in Fish

36. Vertebrate Thermoregulation
Ectothermic – obtaining body heat from the environment
Poikilothermic – non-regulatory, the body temperature is the same as the ambient environment
Regulatory ectotherms – maintain a consistent body temperature through physiological and behavioral means

37. Vertebrate Thermoregulation
Endothermic – body heat is produced internally (homeothermic)
Fish are poikilothermic because water is a heat sink

38. Buoyancy in Fish
Squalene (liver oil)

39. Buoyancy in Fish Physostomous bladder
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
Physostomous bladder

40. Physoclistous bladder
Buoyancy in Fish
aaaaaa
aaaaaaa
Physoclistous bladder

41. Fish Feeding Strategies
Most fish are carnivores
Most ocean species are suspension feeders
Some are scavengers
A few species are parasites
A few species are herbivores
A few species are omnivores

42. Fish Reproductive Adaptations
Oviparous - egg laying
Ovoviviparous - retention of eggs
Viviparous – live birth
All three methods are found in cartilaginous and bony fishes
Cartilaginous fish are internal fertilizers while most bony fish are external fertilizers

43. Fish Reproductive Adaptations
Diadromous - fish that make “two runs” in their life to live and reproduce
Anadromous - fish that “run up” - salmon
Catadromous - fish that “run down” - eels
Parthenogenesis - no males required, females produce diploid eggs - Amazon molly

44. Amphibian Taxonomy Kingdom - Animalia Phylum - Chordata
Subphylum - Vertebrata
Superclass - Gnathostomata
Class - Amphibia
Order - Gymnophiona (caecilians)
Order - Caudata (salamanders)
Ex. Ambystoma, Necturus
Order - Anura (frogs)
Ex. Rana, Bufo

45. Class Amphibia All five chordate hallmark characteristics
Endoskeleton of bone
Thin, gland rich skin with no scales or claws
Large mouth - all members carnivores
Closed double looped circulatory system with a ventral three chambered heart
Respiration - lungs, gills or cutaneous
Regulatory ectotherms

46. Class Amphibia
Excretion through opisthonephric kidneys and urea as the primary nitrogenous waste
Nervous system with a brain and dorsal nerve cord - well developed sight and hearing
Reproduction – dioecious, some internal, others external fertilizers, some metamorphosis
Most are tetrapods

47. Order Gymnophiona Caecilians Legless, elongated worm-like bodies
Fossorial, tropical & subtropical organisms
Most are blind, with smell and touch being the best senses
Eggs are laid in moist soil
Some species are viviparous

48. Order Caudata Salamanders, newts, amphiumas, sirens
Most have four legs & all have a tail
Some aquatic, some terrestrial
Respiration by gills, skin and lungs
Internal fertilization
Metamorphosis and direct development
Paedomorphosis common

49. Order Anura Frogs All have four legs and no tail (one exception)
Some aquatic, some terrestrial
Respiration by skin and lungs
Good vision and nictitating membranes
External fertilization
Metamorphosis and direct development

50. Amphibian Evolutionary Pressures
Respiration
Thermoregulation
Support
Ecological diversity

51. Amphibian Respiratory Strategies
Cutaneous
Pulmonary
Buccopharyngeal

52. Amphibian Respiratory Strategies
Gills

53. Amphibian Circulation

54. Amphibian Circulation

55. Amphibian Thermoregulation
Many amphibians are regulatory ectotherms, using physiological and behavioral means
Aquatic species and salamanders are poikilothermic, but other terrestrial species will drop to this level of thermoregulation during hibernation and estivation

56. Amphibian Metamorphosis

57. In caudatans there are two forms of neotony - obligate and facultative
Caudatan Development
Remember!
Neotony - a process in which the growth rate is slowed to the extent that sexual maturity is reached before the ancestral adult form is obtained
In caudatans there are two forms of neotony - obligate and facultative

58. Obligate neotony
Facultative neotony