Systematics & Classification MARE 390 Dr. Turner

1. Systematics & Classification MARE 390 Dr. Turner

2. Systematics & Classification Systematics - Study of biological diversity Phylogeny – evolutionary history of a particular group of animals Why study? Framework for interpreting biological diversity

3. Terms & Concepts Ancestral – preexisting character; primitive Derived – new character state ancestral – locomotion with hind limbs derived – locomotion with body/tail Derived characters are used to link groups – specifically monophyletic groups

4. Terms & Concepts Monophyletic – a group of taxa that consist of a common ancestor plus all descendants of that ancestor Paraphyletic and polyphyletic – include a common ancestor and some descendants

5. Terms & Concepts Paraphyletic - group contains the most recent common ancestor but does not include all the descendants of this common ancestor e.g. - class Reptilia is paraphyletic because that class does not include birds (class Aves), which are descended from reptiles Polyphyletic - does not contain the most recent common ancestor of all its members e.g. -homoetherms are polyphyletic - contain both mammals and birds, but the most recent common ancestor of mammals and birds were piokilotherms

6. Terms & Concepts Diphyletic - a taxonomic group of organisms derived from two separate ancestral lines now replaced by poly & para e.g. – pinnipeds mono or diphyletic Cladogram – a branching diagram that conceptually represents the best estimate of phylogeny

7. Terms & Concepts Homology – similarity of features resulting from common ancestry Homoplasy – similarity not due to homology; (analogous) structures that are the result of convergent evolution or reversal Convergent (parallel) – independent evolution of a similar feature in 2 or more lineages Reversal – loss of a derived feature coupled with establishment of ancestral

8. Who did the what now? Homology Elephant seal Walrus Common ancestor had flippers

9. Who did the what now? Homoplasy - convergent Elephant seal Bottlenose dolphin Common ancestor lacked flippers

10. Who did the what now? Homoplasy - reversal Elephant seal Harp seal Claws not in ancestral phocids but in terrestrial arctoid carnivores

11. How to do – that thing you do Cladograms are constructed by: 1. Naming and defining all taxa in group 2. Select/define characters for each taxon 3. Arrange characters 4. Determine whether each character is ancestral or derived 5. Construct all possible cladograms by grouping taxa based upon common shared derived characters

14. Testing Phylogenetic Hypotheses Parsimony - least complex explanation for an observation Maximum parsimony - the preferred phylogenetic tree is the tree that requires the least number of evolutionary changes

15. Testing Phylogenetic Hypotheses

16. Taxonomy & Classification Taxonomy – the description, identification, and classification of species Within past 10 years: 2 beaked whales described; 1 resurrected New dolphin species described 3 forms (subspecies) of Orcinus orca New species of balaenopterid described

17. Australian Snubfin Dolphin (Orcaella heinsohni)

18. Pygmy beaked whale (Mesoplodon peruvianus)

19. Omura’s Whale Balaenoptera omurai Pygmy Bryde's Whale (Eden's Whale) Balaenoptera edeni

20. Orcinus orca subspecies? Resident Transient Offshore

22. Evolutionary Biogeography Biogeography – study of geographic distribution of organisms (past & present) Patterns in distributions of taxonomic groups/species and interprets aspects of both ecology & evolution 1. How did species occupy present range? 2. What geologic events shaped distribution? 3. How are regional species related?

23. Ecological Factors Several adaptations to the ocean Buoyancy – seawater Friction resistance to swimming Poor light transmission Osmotic challenges – hyperosmotic Heat loss to water Water temperatures Primary productivity spatial & temporal variation

24. Temperature & Sea Ice Marine mammals in contact with cold water Heat capacity of water 25X air Sea ice very important to marine mammals Fast ice – attached to land; Weddell, elephant Pack ice – free floating; walrus, Steller’s, harp

25. Primary Productivity Availability of food established by: 1. Pattern of primary production 2. Number of trophic levels between 1° producer and marine mammals consumer Sirenians – directly on 1° production Mysticetes – few trophic levels Odontocetes & pinnipeds – 5+ levels

26. Particle Size & Biomass

27. Seasonal Patterns in 1° Production

28. Variation in Ocean Production Water temperature & food resources vary Upwelling ENSO – El Nino-Southern Oscillation NAO – North Atlantic Oscillation

29. Present Patterns of Distribution Two major patters: 1. Cosmopolitan – wide distributions; inhabiting most of the world’s oceans e.g. – common dolphin, harbor seal 2. Disjunct – species pair distribution separated by a geographic barrier e.g. - walrus

30. Present Patterns of Distribution Endemic – confined to a particular geographic region e.g. – Hawaiian monk seal Circumpolar – having distribution around the poles e.g. – narwhal & beluga Antitropical – species pair – one in northern one in southen hemisphere e.g. N & S right whale dolphin

31. Past Patterns of Distribution Past arrangements of continents & ocean basins have affected the distribution of marine mammals Corridor – route that permits spread from one region to another Barriers to dispersal: physical (continents), climactic (equator), biotic (low productivity)

32. Events Affecting Distribution 1- Early cetaceans 2- Early sirenians

33. Continents in Early Eocene

34. Continents in Early Miocene (20mya) 1- Early pinnipeds 4- Early pinnipeds

35. Continents in Middle Miocene (12mya) 1- Early phocids, 2 – Monachines & Odobenids, 3-4 - Phocines