EVOLUCION

cambio con modificacin

La creacin bblica

Jean Baptiste de MonetCaballero de Lamarck

How does evolution occur: the mechanism

Lamarckian evolution: Inheritance of acquired characteristics;Lack of support from genetics and experimental biology;

George Cuvier

Charles DarwinAlfred Wallace

How does evolution occur: the mechanism

Evolution happens slowly and gradually, through non-random survivability (selection) of features in a parent population;

Mendel

Ortognesis

Teilhard de Chardin(Oonosfera)

George Gaylord Simpson

The evolution of horses: Traditional interpretationOriginated in North America, in the Eocene;Increasing body size;Increasing tooth-crown height;Decreasing number of toes;Traditionally interpreted as a single lineage, gradual, phyletic evolution;

The evolution of horses: New interpretationNew fossil discoveries reveal that there existed many fast evolving lineages;Branching events (speciation events) follow punctuated equilibrium model;Evolutionary trends found in multiple lineages;Evolutionary trends driven by climatic and ecological changes (woodland browsers to grassland grazers);

Niels EldredgeStephen J. GouldEquilibrio interrumpido

Evolutionary Pattern: Phyletic Gradualism vs. Punctuated Equilibrium

Punctuated EquilibriumObservations:Morphological changes mostly occur when species branch to form new species (speciation events);Stasis between speciation events;Evolutionary rate may not be constant, fast at speciation events, slow between speciation events;

MechanismAllopatric speciation: Peripheral subpopulations are small, easy to isolate, and evolve faster;

Phyletic gradualism and punctuated equilibrium are two alternative modes of speciation; both modes have been seen in the fossil record.

Estado actual: Nueva sntesis

Evidencias de la evolucin

Evidence for Evolution

Homologous structures;Structures in different species and with strikingly different functions are built from the same basic blueprint, indicating that they evolved from a common ancestor; these are called homologous structures

Evidence for Evolution

Evolution of whales from even-toed ungulates; De Muizon, 2001, Nature, 413:259-260

Evidence for Evolution

Biologa del desarrollo: Evo Devo

Biologa/Genticadeldesarrollo(EvoDevo)

GENESestructuralesGENESReguladores(HOX-HOMEOBOX)

Seleccin NaturalSupervivencia y reproduccin diferencial de los individuos mejor adaptados

Darwins mechanism of evolution: Natural Selection and Phyletic Gradualism

Galapagos finches have strikingly different beaks, -- an adaptation to different diets

Adaptacin

Kettlewell, 1959

estabilizadoradireccionaldiversificadora

Megaloceros ginganteum

REPRODUCCION DE MODELOS DE GRAPTOLITESPARA EL ESTUDIO DE LA BIOLOGIA FUNCIONAL

Hiperadaptacionismo

The pelvis and femur of a whale are vestigial organs

Limitaciones al crecimiento

(morfologa construccional)

ESPECIES

Species as a dynamic biological entity

Species:A group of organisms that have general structural, functional, developmental, and genetic similarities and that are able to interbreed to produce fertile offspring;Under natural conditions, individuals of difference species cannot breed to produce fertile offspring; species exist in reproductive isolation and there is no genetic flow between species;New species arise through reproductive isolation and natural selection;

How many living species?Millions have been described, many are insects. Millions more remain to be discovered and described.

How many species existed on the Earth?No reliable estimate. Perhaps as many as 50 billion. Only one in a thousand species is still alive. Most went extinct.

Especies gemelas

Especies politpicas

Especiacin geogrfica

El problema de la especie en PaleontologaEspecies gemelas y politpicasDimorfismo sexualSesgos de preservacinRepresentacin parcial de organismosEscasez de individuosImposibilidad de cruzamiento-informacin genticaEl caso de Metrarabdotos (briozoo)

MorfoespecieCronoespecieEstablecer lmites entre especiesNecesidad de series muy completas con muy buen registro

El problema de la especiacinen Paleontologa

Melanopsis

CladognesisAnagnesisEstasisInterrupcinAnagnesisInterrupcinGRADUALISMOFILETICOEQUILIBRIOINTERRUMPIDOANAGENESISINTERRUMPIDACAMBIO MORFOLOGICOTIEMPOMODELOS EVOLUTIVOS

Macroevolucin1. Aparicin de taxones superiores2. Tasa de cambio morfolgico3. Seleccin-tra de especies4. Morfologa de clados5. Disparidad morfolgica

(Wallace Arthur 2004)Aparicin de taxonessuperiores

Heterocronas

Tasa de cambio morfolgico

Fsiles vivientesLimulus

Seleccin-tra de especies

Morfologa de clados

Interaccin entre clados

Disparidad morfolgica

Evolucin de comunidades

(Futuyma, 1986)

(Phillips, 1860)

(Darwin, 1859)

Sesgos:

Dependientes del tiempovolumen de rocas y rea cubiertapreservacin diferencialefecto monogrfico (inters)

Independientes del tiempodificultad de reconocer y registrar especiesregistro marino vs continentalformas con esqueleto vs sin esqueleto

(Sepkoski)(Stanley, 2007)(Sepkoski, 1997)

Paleozoic plateau

Extinciones

Sepkoski

Tipos de extincin en masa

gradual

catastrfica

Problemas

Tipos de seleccin en las extinciones en masaSeleccin anatmica-ecolgica

Seleccin taxonmica

Seleccin geogrfica

Causas de la extincin en masaTerrestres:

Nivel del marAnoxiaVulcanismo intensoClima globalExtraterrestres:

Impacto meteortico

Nivel del mar

Anoxia

Vulcanismo

Impacto meteortico

(Archibald, 1996)AREA NO MARINA (106 m2)TASA DE EXTINCIONIMPACTOSY VOLCANISMOPERMO/TRIASTRIASICO SUPERIORK/T

Causas de la extincin en masaInteracciones biticasSEXTA EXTINCIN

EXTINCION DEL DODO, Didus ineptus (Hutchinson, 1894)