Video Experimental Relacionado
Updated: Jul 2, 2025
05:07
Using Looming Visual Stimuli to Evaluate Mouse Vision
Published on: June 13, 2019
11.3K
Una base morfológica para la evolución dependiente del camino de los sistemas visuales
Rebecca M Varney1, Daniel I Speiser2, Johanna T Cannon1
1University of California, Santa Barbara, Santa Barbara, CA, USA.
Science (New York, N.Y.)
|February 29, 2024
Resumen
La dependencia del camino, o la historia evolutiva, da forma a rasgos complejos como la visión en los chitones. Este estudio revela cómo la estructura de la concha limita la evolución de sus ojos, lo que demuestra resultados predecibles pero variables en los sistemas naturales.
Área de la Ciencia:
- Biología evolutiva
- Patrones macroevolutivos
- Restricciones del desarrollo
Sus antecedentes:
- La dependencia de la trayectoria influye en la previsibilidad macroevolucionaria al restringir las trayectorias evolutivas.
- Demostrar la dependencia de la trayectoria en los sistemas naturales es un reto debido a la falta de réplicas independientes.
- Los sistemas visuales distribuidos en los chitones ofrecen un modelo para estudiar la evolución de rasgos complejos.
Objetivo del estudio:
- Demostrar la dependencia de la trayectoria en la evolución de rasgos complejos dentro de las poblaciones naturales.
- Investigar el papel de las limitaciones del desarrollo en la configuración de los resultados macroevolutivos.
- Para analizar la evolución de los sistemas visuales en los chitones.
Principales métodos:
- Análisis comparativo de linajes de chitón con diferentes estructuras de placas de caparazón.
- Examen del número de aberturas para los nervios sensoriales en las placas de la concha.
- Evaluación morfológica de la complejidad del sistema visual (número de manchas oculares).
Principales resultados:
- Dos tipos de sistemas visuales distribuidos evolucionaron independientemente dos veces en los chitones.
- El número de aberturas nerviosas sensoriales en las placas de la concha limita el tipo de sistema visual evolucionado.
- Los linajes con más aberturas evolucionaron miles de manchas oculares, mientras que aquellos con menos evolucionaron cientos.
Conclusiones:
- La evolución de los sistemas visuales de los chitones es un proceso rápido y dependiente de la trayectoria.
- Las limitaciones del desarrollo, específicamente la morfología de la concha, dictan los resultados macroevolutivos.
- Estos resultados son deterministas (restringidos) y estocásticos (variables).
Videos de Conceptos Relacionados
01:26Visual System
581
Light enters the eye through the cornea, a transparent, dome-shaped surface covering the surface of the eyeball that helps to direct and focus incoming light. This light is then channeled toward the pupil, an adjustable opening whose size is controlled by the iris. The iris, a pigmented muscle, regulates the amount of light entering the eye by contracting or dilating the pupil, thereby ensuring optimal light levels for clear vision.
Once through the pupil, the light passes through the lens, a...
Once through the pupil, the light passes through the lens, a...
581
01:24Vision
53.3K
Vision is the result of light being detected and transduced into neural signals by the retina of the eye. This information is then further analyzed and interpreted by the brain. First, light enters the front of the eye and is focused by the cornea and lens onto the retina—a thin sheet of neural tissue lining the back of the eye. Because of refraction through the convex lens of the eye, images are projected onto the retina upside-down and reversed.
53.3K
01:20Anatomy of the Eyeball
7.1K
The eye is a spherical, hollow structure composed of three tissue layers. The outer layer — the fibrous tunic, comprises the sclera — a white structure — and the cornea, which is transparent. The sclera encompasses some of the ocular surface, most of which is not visible. However, the 'white of the eye' is distinctively visible in humans compared to other species. The cornea, a clear covering at the front of the eye, enables light penetration. The eye's middle...
7.1K
01:22Photoreceptors and Visual Pathways
6.0K
At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category,...
6.0K
02:37Gene Duplication and Divergence
6.1K
The seminal work of Ohno in 1970 popularized the idea of gene duplication and divergence. DNA sequence comparison studies reveal that a large portion of the genes in bacteria, archaebacteria, and eukaryotes was generated by gene duplication and divergence, indicating its critical role in evolution.
The duplicated copies of the gene are called Paralogs. Paralogs with similar sequences and functions form a gene family. Across several species, a large number of gene families are...
The duplicated copies of the gene are called Paralogs. Paralogs with similar sequences and functions form a gene family. Across several species, a large number of gene families are...
6.1K
02:55The Evidence for Evolution
42.7K
Genetic variations accumulating within populations over generations give rise to biological evolution. Evolutionary changes can result in the formation of novel varieties and entire new species. These changes are responsible for the diverse forms of life inhabiting the planet. The evidence for evolution suggests that all living organisms descended from common ancestors.
42.7K