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There have been five major extinction events throughout geological history, resulting in the elimination of biodiversity, followed by a rebound of species that adapted to the new conditions. In the current geological epoch, the Holocene, there is a sixth extinction event in progress. This mass extinction has been attributed to human activities and is thus provisionally called the Anthropocene. In 2019 the human population reached 7.7 billion people and is projected to comprise 10 billion by...
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01:25Rab Cascades
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Rab GTPases act in a regulated cascade during membrane fusion, helping the lipid bilayers mix. The Rab family of proteins are active when bound to GTP, and inactive when bound to GDP. Hence, they act as guanine nucleotide-dependent molecular switches. Rab-GTP recognizes and binds to long or short-range tethering proteins to capture the target vesicle. These tethers coordinate with SNAREs on the vesicle and the target membrane to assemble the trans SNARE complex that locks the mixing bilayers.
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01:32What is Natural Selection?
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02:07Conservation of Declining Populations
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Conservation of declining population focuses on ways of detecting, diagnosing, and halting a population decline. The approach uses methods to prevent populations from going extinct.
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00:53Migration
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01:39Keystone Species
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Measures of species biodiversity, such as richness (i.e., the number of species present) and evenness (i.e., their relative abundance), describe an ecological community’s structure. Many factors affect community structure, including abiotic factors (e.g., sunlight and nutrients), disturbances (e.g., fire or flood), species interactions (e.g., predation or competition), and chance events (e.g., foreign species invasion). Certain species—such as keystone species—also play a...
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Updated: Sep 13, 2025
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Removal of Exogenous Materials from the Outer Portion of Frozen Cores to Investigate the Ancient Biological Communities Harbored Inside
Published on: July 3, 2016
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Resumen
El norte de Alaska
Área de la Ciencia:
- Ciencias del medio ambiente
- Hidrología
- Ecología
Sus antecedentes:
- La construcción de presas y estanques está alterando el paisaje ártico.
- Estas alteraciones afectan la hidrología y los ecosistemas de la región.
Objetivo del estudio:
- Para analizar la transformación del paisaje en el norte de Alaska debido a las presas y los estanques.
- Comprender los impactos ecológicos e hidrológicos de estos embalses de agua.
Principales métodos:
- Análisis por teledetección de los cambios de paisaje.
- Modelado hidrológico para evaluar las alteraciones del flujo de agua.
- Encuestas ecológicas para determinar los impactos en la biodiversidad.
Principales resultados:
- Se observaron alteraciones significativas en la distribución de las aguas superficiales.
- Se detectaron cambios en los patrones de vegetación y la estabilidad del permafrost.
- Impactos documentados en los hábitats de la vida silvestre acuática y terrestre.
Conclusiones:
- Las presas y los estanques están transformando los paisajes del norte de Alaska.
- Estos cambios tienen profundas implicaciones para los ecosistemas regionales y la hidrología.
- Se necesitan más investigaciones para comprender plenamente las consecuencias a largo plazo.