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Evolución de la endotermia en los peces: mapeo de rasgos fisiológicos en una filogenia molecular
B A Block1, J R Finnerty, A F Stewart
1Department of Organismal Biology and Anatomy, University of Chicago, IL 60637.
Science (New York, N.Y.)
|April 9, 1993
Resumen
La endotermia, la capacidad de generar calor interno, evolucionó independientemente tres veces en peces escombridos. Este rasgo facilitó la expansión en aguas más frías, no mejoró la capacidad aeróbica.
Área de la Ciencia:
- Biología evolutiva Biología evolutiva.
- Ictiología Ictiología.
- Filogenética molecular Filogenética molecular
Sus antecedentes:
- La endotermia, o la capacidad de mantener una temperatura corporal más alta que el ambiente, es un rasgo complejo con diversos orígenes evolutivos.
- Los peces Scombroidei, incluidas las caballas, los atunes y los billfishes, exhiben variadas estrategias endotérmicas, lo que los convierte en un grupo modelo para estudiar su evolución.
Objetivo del estudio:
- Para investigar la filogenia molecular del suborden Scombroidei.
- Para determinar la historia evolutiva y los orígenes independientes de la endotermia dentro de este grupo de peces.
- Comprender las presiones selectivas que impulsan la evolución de la endotermia craneal.
Principales métodos:
- Secuenciación directa del gen mitocondrial del citocromo b para construir una filogenia molecular.
- Mapeando la distribución de las especies endotérmicas en el árbol filogenético.
- Correlación de la evolución de la endotermia con los factores ambientales, específicamente la temperatura del agua.
Principales resultados:
- Se estableció una filogenia molecular para los Scombroidei.
- La evidencia sugiere tres orígenes evolutivos independientes de la endotermia craneal (calentamiento del cerebro y la retina) dentro de este suborden.
- Estos orígenes independientes coincidieron con la colonización de ambientes acuáticos más fríos.
Conclusiones:
- La endotermia craneal en los peces probablemente evolucionó como un mecanismo para la expansión del nicho térmico, lo que permite la explotación de hábitats más fríos.
- La evolución de la endotermia en este grupo no fue impulsada principalmente por la necesidad de aumentar la capacidad aeróbica.
- Este estudio pone de relieve la importancia adaptativa de la endotermia en respuesta a los desafíos ambientales.
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