2. Comparative Anatomy Biology 440 Fall semester TuTh 10:00 – 11:15 G23 Lab at 1:00 in 3106 or 3108

3. Comparative Anatomy Biology 440 Spring semester TuTh 11:30 – 12:45 G23 Lab at 2:00 in 3106 or 3108

4. Dr. Susan Raylman Office hours: Mon Wed 1:15 – 3:00 4234 LSB Best way to contact me: sphilhow@wvu.edu or Susan.Raylman@wvu.edu

5. http://www.as.wvu.edu/~sraylman/compara tive/ http://www.as.wvu.edu/~sraylman/compara tive/Texts: Website

6. Labs start next week on Tuesday Don’t wear your best clothes to lab No food or drink Arrive on time Go to either 3106 or 3108

7. Evacuation Exit building from either of the two main doors Move away from the building while avoiding parking lots Do not congregate near building or parking lots

8. Why study comparative anatomy? shark cranial nerves human cranial nerves

9. Arteries leaving the heart

10. perch mudpuppy pigeon bison Basis for comparative anatomy:  many animals have a similar basic underlying structure

11.  Your Inner Fish Your Inner Fish

12.  George Cuvier (1769-1832) - founder of paleontology, comparative anatomy.  Richard Owen (1804-1892) - grouped similar organisms into “archetypes”. Goal is to understand an overall “Plan”

13. Owen’s general plan for vertebrates

14. Charles Darwin - The Origin of Species 1858 We see similar designs because organisms share a common ancestry

15.  Why do organisms share common ancestry?  How does natural selection work?

16. 1. There is variation within a species concerning a particular trait. 2. This variation is associated with differing fitness levels. 3. The variation is inheritable. Then: Individuals with traits associated with higher fitness will have more genetic representation in future generations. i.e. their genes become more prevalent.

17. 1. There are physical limitations concerning animal design.  Sometimes the genetic variation is not there. So what does this mean for us in comparative anatomy? ex: Dolphin

18. 2. Evolution is restricted by the raw material that is available. How we see natural selection in anatomy Ex: Giant panda

21. 3. Sometimes anatomy has no apparent function How we see natural selection in anatomy ex: Whale hips dolphin embryo

23.  Vestigial structures: Why do small remnants remain? vestigial toe of penguin

24. Hollywood version of evolution…

25. Organisms aren’t stepping stones for more “advanced” creatures… Ladder of progress vs. bush

26. All organisms are linked by the passage of genes along the branches of the phylogenetic “tree”

31. Homologous structures  share common ancestry, may have different functions

32. Homologous structures share common ancestry may have different functions Analogous structures (homoplasic) same function may have different ancestry ex: bat wing & butterfly wing panda “thumb” and human thumb

33. Ancestral structure - state of a structure in earlier forms - “primitive” Derived structure - state in later forms “advanced” 46 million years ago 50 million years ago

34. Ancestral structure - state of a structure in earlier forms - “primitive” Derived structure - state in later forms “advanced” Synapomorphy - a derived structure that is shared by a group of organisms (and not found in others)

36. Zeroing in on Chordata Old 5 kingdom arrangement

37. Some animal phyla Radial Bilateral Coelomates Deuterostomes Protostomes

38. Coelomates

39.  Echinodermata, Hemichordata, Chordata are all deuterostomes some echinoderms hemichordata

40. Deuterostomes have indeterminate development (as opposed to determinate) Linking echinoderms and chordates

41.  Blastomeres: Embryonic cells formed during embryonic cleavage soon after fertilization.

42. Arrangement of blastomeres Spiral arrangement Radial arrangement

43. At 8 blastomere stage...

44. Blastula stage - hollow ball of cells Making the gut tube

45. Then blastula sinks in - indentation forms (blastopore) Gastrulation

46. Protostome Deuterostome anus blastopore mouth blastopore

47.  Protostome coelum forms in mesoderm  Deuterostome coelum buds off from developing gut Making coelum

48. Chordates have the following structures at some time in their life cycle. 1. Dorsal hollow nerve cord 2. Notochord 3. Pharyngeal slits or pouches 4. Post-anal tail 5. Endostyle/thyroid gland

49. Seas when chordata started:

50. Flexible, dorsal to coelom - ventral to nerve cord. Chief body support in early chordates. Notochord amphioxus X-section

51. p.160

52. It helps to organize later development Notochord is mostly replaced by vertebral column in vertebrates. Notochord

53. In mammals, a remnant of notochord remains in intervertebral disks (nucleus pulposus). shorter size at old age herniated disk

54.  Formed by an invagination of ectoderm Dorsal hollow nerve cord X-section through dorsal portion of embryo p.140

56. p.141

57. Slits are not present in all chordates, they may instead be pouches present during development Pharyngeal slits Branchial or pharyngeal region

58. 1. Area caudal to the anus, not containing coelom. 2. Used for locomotion in fish; various functions in tetrapods; may be lost. Post anal tail anus