Transcript
B Y K A I T L I N P R I N C E
T E X A S A & M C O R P U S C H R I S T I
P R O F E S S I O N A L S K I L L S
B I O L 2 2 0 0 . 0 0 3
Morphological and behavioral differences between separate populations of Orcinus orca
Outline
Overview of O. orca Importance of classification
Definition of species and ecotype
Methods
Conclusion
Discussion
Current Taxonomy
Animalia
Chordata
Mammalia
Cetacea
• Odontoceti
Delphinidae
•Orcinus
•orca
Classified as a dolphin
Common name, “killer whale”, misleading
Most widely distributed species after humans
Classification can effect conservation status
Overview of O. orca
Dorsal Fin
Saddle PatchEye Patch
Adult Male
Adult FemaleJuvenile
Figure 1: Diagram of O. orca (1)
Social Structure of O. orca
Pods: small groups of directly related individuals that constantly travel, hunt and live together
Clans: related pods that have overlapping ranges and occasionally mingle
Communities: sets of clans that regularly intermingle
Species Ecotype
Often defined as a group of organisms capable of interbreeding and producing fertile offspring in the wild
Describes a genetically distinct geographic variety, population or race within species which is adapted to specific environmental conditions
Definitions of Species and Ecotype
Methods: Observations
Morphological differences Size/shape of eye patch
Presence of dorsal cape
Size/shape of dorsal fin
Behavioral differences Feeding patterns
Movement patterns
Group size
Reviewing available photographs
Fig. 3: Type A attacking a minke whale (Pitman, Ensor, 2003)
Type A Type B
Typically feed on minke whales
No cape markings
Medium-sized eye patch
Very large eye patch
Well-defined cape markings
Lighter, grey colored body
Typically feed on seals
O. orca Populations of the Antarctic
Fig. 4: Type A (Pitman, Ensor, 2003) Fig. 5: Type B (Pitman, Ensor, 2003)
Type C Physical Comparisons
Largest pods
Eye patch slanted forward; “smudged” appearance; small, gray body with cape
Typically feed on Antarctic cod
O. orca Populations of the Antarctic cont.
Fig. 6: Type C (Pitman, Ensor, 2003)Fig. 7: Comparison of Types
(http://en.wikipedia.org/wiki/Killer_whale)
Comparison of Type A and Type B Movements
Fig. 11: Comparison of Type A and Type B Movements (Pitman, Ensor, 2003)
Residents Transients
Primarily eat fish
Live in matrilineal pods
More vocalizations
Most extensively studied group
Exclusively eat marine mammals
Typically live in groups of three
Less vocalization; complex dialects
O. orca Populations of the North American West Coast
Fig. 8: Resident dorsal fin (Baird, Abrams, Dill, 1992)
Fig. 9: Transient dorsal fin (Baird, Abrams, Dill, 1992)
Comparison of Residents and Transients
Fig. 10: Differences between residents and transients (Baird, Abrams, Dill, 1992)
Methods: Satellite Tracking
Satellite tracking is a useful way to track individuals
Small dart with transmitter attached
TemporaryFig. 12: Satellite tracking (Russell, Pitman, Ballance, 2008)
Type B Individual Type C Individual
Comparison of Type B and Type C Movements
Fig. 13: Satellite tracking (Russell, et. al., 2008)
Fig. 14: Satellite tracking (Russell, et. al., 2008)
Culture Application to O. orca
Consists of the beliefs, behaviors, objects, and other characteristics common to the members of a particular group or society
Have been shown to teach their young certain behaviors (namely hunting)
Pass on specific dialects from one generation to the next
Behaviors NOT common to all members of the species, only that pod or clan
Definition of Culture and Application to O. orca
Type D (Antarctic)Offshore (North American West Coast)
Identified by mass stranding in New Zealand/handful of sightings
Unknown diet
Extremely small eye patch; bulbous head
Primarily feed on schooling fish
Live far from shore; rarely in shallow waters
Live in large groups of 20-50, sometimes more
Other Possible Groups
Conclusion
Evidence for separate species or subspecies
Morphological differences
Behavioral differences
Geographic isolation
Fig. 15: Type B spy-hopping (Pitman, Ensor, 2003)
Discussion
More information is needed on the lesser known groups
Genetic analysis of populations would provide evidence of reproductive isolation
Important to determine conservation status (endangered)
Fig. 16: Type C mother and calf (3)
References
Baird, Robin. Abrams, Peter. Dill, Lawrence. Possible indirectinteractions between transient and resident killerwhales: implications for the evolution of foragingspecializations in the genus Orcinus. 1992. J. Oecologia.89: 125-132.
Pitman, Robert. Ensor, Paul. Three forms of killer whales (Orcinusorca) in Antarctic waters. 2003. J. Cetacean ResourceManagement. 5(2): 131-139.
Russell, Andrews. Pitman, Robert. Ballance, Lisa. Satellite trackingreveals distinct movement patterns for Type B and Type Ckiller whales in the southern Ross Sea, Antarctica. 2008. J.Polar Biology. 31: 1461-1468.
Image References
(1) http://www.google.com/imgres?imgurl=http://www.acsonline.o rg/factpack/images/KillerWhaleRangeMap.jpg&imgrefurl=http://www.acsonline.org/factpack/orca/kidDistribution.html&usg=__lUmoZMbLL_QUoq3v9uxbWGeenXY=&h=430&w=720&sz=168&hl=en&start=0&zoom=1&tbnid=oOe7Pvao84Mf8M:&tbnh=112&tbnw=188&ei=Ybl3Tc6BDurj0gHC9uSkBw&prev=/images%3Fq%3Dkiller%2Bwhale%2Bdistribution%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26sa%3DX%26rls%3Dorg.mozilla:en-US:official%26channel%3Ds%26biw%3D1366%26bih%3D607%26tbs%3Disch:1&um=1&itbs=1&iact=hc&vpx=117&vpy=111&dur=75&hovh=173&hovw=291&tx=120&ty=114&oei=Ybl3Tc6BDurj0gHC9uSkBw&page=1&ndsp=19&ved=1t:429,r:0,s:0
(2) http://www.acsonline.org/factpack/images/orca-family-med.gif
(3) http://en.wikipedia.org/wiki/File:Type_C_Orcas.jpg
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