Chapter 1(part2) by kardong

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  • 1. EvolutionaryMorphologyPart 2 of Chapter 1By Geonyzl Alviola

2. Function and Biological Role Function = is restricted to mean theaction or property of a part as itworks in an organism. Biological Role = (or just role)refers to how the part is used in theenvironment during the course ofthe organisms life history. 3. For example1. Cheek muscle Function: to close the jaw Biological Role: for foodprocessing (chewing) Biological Role: (biting) forprotection against threat 4. For example (one part withseveral function)2. quarate bone (in reptiles Function: to attach the lower jawto the skull. It also functions totransmit sound waves to the ear. Biological role: feeding (foodprocurement) and hearing(detection of enemies or prey) 5. Example Function? Biological Role? 6. Functions of a part are determined largely inlaboratory studies; biological roles areobserved in field studies.Inferring biologicalroles only from laboratory studies can bemisleading 7. Preadaptation Preadaptation means that a structure orbehavior possesses the necessary form andfunction before (hence pre-) the biologicalrole arises that it eventually serves. In other words, a preadapted part can dothe job before the job arrives 8. For example: Bird Feather Story feathers likely evolved initially in birds (or in theirimmediate ancestors) as insulation to conservebody heat. Like hair in mammals, feathersformed a surface barrier to retard the loss ofbody heat. For warm-blooded birds, featherswere an indispensable energy-conservingfeature. Today, feathers still play a role inthermoregulation; however, for modern birds,flight is the most conspicuous role of feathers.Flight came later in avian evolution. 9. Phylogeny can be summarized in graphicschemes, or dendrograms, thatdepict treelike, branchedconnections between groups. Dendrograms summarizeevolutions course 10. Of Beanstalks and Bushes 1896, Ernst Haeckel wrote The Evolution ofMan Evolution does not proceed up a singleladder, but bushes outward along severalsimultaneous courses. Humans share the current evolutionarymoment with millions of other species, allwith long histories of their own. All adapted in their own ways to their ownenvironments. 11. The apparent discreteness of species orgroups at the current moment is partly dueto their previous divergence. When followed back into their past, theconnectedness of species can bedetermined. A dendrogram showing lineagesin three dimensions (figure 1.22)emphasizes this continuity. 12. DenrogramsIt is a summarized graphic representationof the course of evolution or phylogeny- it is also used to express relativeabundance and diversity.- presented like a branching tree or anyform. 13. Gradual presentation / Abrupt dendogram 14. A clade is a grouping that includes a commonancestor and all the descendants (living andextinct) of that ancestor. 15. Monophyletic clade- it includes anancestor and all itsdescendantsParaphyletic clade- one that includesa common ancestorand some but notall, of itsdescendants.Polyphyletic cladeIs one that doesnot share animmediate commonancestors 16. Parallelism and ConvergenceParallelism is evolutionary change in two ormore lineages such that correspondingfeatures undergo equivalent alterationswithout becoming more or less similara bThe ancestoris common inboth a and b 17. Kangaroo ratNorth AmericaJerboasAfrica and Asia 18. ConvergenceIs evolutionary change in two or morelineages such that corresponding featuresthat were formerly dissimilar become similarSimilarity BAbetween A and Bevolved fromdifferent lineages 19. For example 20. Studying phylogenyStudying the history of an animalTracing its relativesAssociating its resemblance=======> Paleontology 21. Paleontology= study the fossils= recovery and restoration= dating the fossils= stratigraphy= indexing= radiometric dating