Name: how humans change biodiversity
Uploaded: 2019-03-11T09:21:43.000Z
Duration: 1 min 50 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

North Carolina K-12 Science Standard Course of Study

9-12

Biology

ecosystems-interactions-energy-and-dynamics

Ecosystems- Interactions, Energy, and Dynamics

LS.Bio.5.2

Threats to Biodiversity

- [Narrador] Aunque la
biodiversidad ha cambiado

a lo largo del tiempo geológico,

subiendo y bajando como resultado

de cinco grandes extinciones en masa

a lo largo de la historia de la Tierra.

La sexta extinción en masa,

conocida como la actual
extinción del Holoceno,

puede atribuirse a las
actividades humanas.

La explosión de la población humana

está en el centro de la
pérdida de biodiversidad actual

que resulta en la pérdida de hábitat,

la explotación excesiva,
la introducción de especies

invasoras y el cambio climático global.

El gran aumento en la
necesidad de recursos

para alimento humano y refugio

ha causado la pérdida de
hábitat para muchas especies.

La deforestación y la
transformación de la tierra para la

agricultura empuja a las
especies fuera de sus hábitats

naturales a zonas domésticas
más pequeñas y fragmentadas

con menos recursos y más
desafíos de supervivencia.

Muchas especies utilizadas
para alimentos y medicinas

están sobre explotadas
más allá de la capacidad

de recuperación de la especie.

Esto es causado por una
alta demanda económica

que no se satisface con
la capacidad reproductiva

de las especies.

Además, la introducción
de especies invasoras

ha dado lugar a cambios
drásticos en los ecosistemas,

eliminando las especies
nativas mediante la depredación

y la competencia por los recursos.

Sin depredadores naturales,
las especies invasoras

causan rápidos descensos
en la biodiversidad.

Finalmente, el aumento
en las emisiones globales

de dióxido de carbono y otros
gases de efecto invernadero

ha resultado en incrementos graduales

en la temperatura global promedio.

Este efecto ha disminuido la
cantidad de espacio habitable

para muchas especies

y ha cambiado los patrones

de actividad migratoria y estacionales.

McLeman, Robert A., Juliette Dupre, Lea Berrang Ford, James Ford, Konrad Gajewski y Gregory Marchildon. "Lo que aprendimos del Dust Bowl: Lecciones de ciencia, política y adaptación". Población y Medio Ambiente 35, no. 4 (1 de junio de 2014): 417–40. [<a href="https://doi.org/10.1007/s11111-013-0190-z" target="__blank">Fuente</a>]

Dobson, Andy P. "Los lobos de Yellowstone y las fuerzas que estructuran los sistemas naturales" PLoS Biology 12, no. 12 (23 de diciembre de 2014). [<a href="https://doi.org/10.1371/journal.pbio.1002025" target="__blank">Fuente</a>]

Bar-On, Yinon M., Rob Phillips y Ron Milo. "La distribución de la biomasa en la Tierra". Actas de la Academia Nacional de Ciencias 115, no. 25 (19 de junio de 2018): 6506. [<a href="https://doi.org/10.1073/pnas.1711842115" target="__blank">Fuentes</a>]

amenazas a la biodiversidad

A lo largo de la historia geológica, han ocurrido cinco grandes eventos de extinción que redujeron drásticamente la biodiversidad, seguidos por la aparición de nuevas especies adaptadas a las condiciones cambiantes. Actualmente, en el Holoceno, estamos viviendo un sexto evento de extinción masiva, impulsado por la actividad humana, lo que ha llevado a algunos científicos a denominar esta era como el Antropoceno.

El impacto humano sobre la biodiversidad es significativo. En 2019, la población mundial alcanzó los 7.700 millones de personas y se espera que supere los 10.000 millones en 2060. En términos de biomasa, los humanos representan el 36% de los mamíferos del planeta, el ganado el 60% y los mamíferos salvajes apenas el 4%. De manera similar, el 70% de las aves son aves de corral, dejando solo un 30% de aves silvestres.

Para reducir nuestro impacto sobre la biodiversidad y el clima, es crucial comprender qué actividades humanas son problemáticas y buscar un equilibrio entre el progreso y la sostenibilidad. Entre las principales amenazas se encuentran la pérdida de hábitats debido al desarrollo urbano y agrícola, el uso excesivo de los recursos naturales y el aumento de emisiones de dióxido de carbono por la industria y el transporte.

<h4>Estudios de caso</h4>

Un ejemplo del impacto humano en el clima ocurrió en la década de 1930 con el Dust Bowl en las Grandes Llanuras de Estados Unidos. Durante los años 20 y 30, la expansión agrícola llevó a la eliminación de la vegetación nativa, que protegía el suelo. Al reemplazarla con cultivos de raíces poco profundas y sumado a una sequía extrema, se desencadenaron tormentas de polvo masivas que afectaron incluso a estados del noreste. Esta crisis, junto con la Gran Depresión, provocó escasez de alimentos y obligó a muchas familias a abandonar sus tierras. El evento resaltó la importancia de una planificación agrícola que considere la biodiversidad y la conservación del suelo.

Otro caso relevante ocurrió en el Parque Nacional de Yellowstone. La caza excesiva de lobos en el siglo XX llevó a un aumento descontrolado de sus presas, como el berrendo y el venado bura. Estos herbívoros consumieron grandes cantidades de árboles jóvenes de álamo (Aspen), lo que redujo su población y provocó una mayor erosión del suelo y la pérdida de hábitats para diversas especies. En años recientes, la reintroducción de lobos en el parque ha coincidido con un repunte en la población de álamos, demostrando el papel clave de los depredadores en el equilibrio ecológico.

<h4>Importancia de la biodiversidad</h4>

La biodiversidad es fundamental para el equilibrio de los ecosistemas, la estabilidad del clima y el desarrollo de nuevas investigaciones en medicina e industria. Su conservación no solo protege a la naturaleza, sino que también garantiza recursos esenciales para el futuro de la humanidad.

Amenazas a la biodiversidad

A lo largo de la historia geológica se han producido cinco grandes extinciones que han provocado la eliminación de la biodiversidad, seguida de un repunte de las especies.

Education

Educación

JoVE Core

Biología

Ecology

Ecología

Biodiversity and Conservation

Biodiversidad y conservación

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

how humans change biodiversity

Human activity is changing biodiversity and pushing Earth toward a sixth extinction event. Earlier mass extinctions ended many species, and then new species spread into the changed environment. Today, the Holocene epoch is seeing a mass extinction linked to human actions, and it is often called the Anthropocene.

Human numbers and human biomass show how large this impact has become. In 2019, the human population reached 7.7 billion and is projected to rise to 10 billion by 2060. By biomass, humans make up about 36% of Earth’s mammals, livestock make up 60%, and wild mammals only 4%. About 70% of all birds are poultry, so only 30% are wild birds.

Several common activities threaten biodiversity. Habitat loss can happen when land is cleared for human development. Over-farming can also damage ecosystems. In addition, factories and vehicles release carbon dioxide, which adds to climate problems. To reduce these effects, people need to understand which activities cause harm and find a sustainable balance between human progress and the needs of future generations.

The Dust Bowl is one clear case of human impact on land and weather. In the 1920s and 1930s, many farmers moved to the Great Plains and clear cut the land. They removed native ground-cover plants so they could plant crops with shallow roots. Then extreme drought and poor farming practices combined to create dust storms that spread debris as far as the northeastern states. Food shortages followed, and many families had to leave their farms.

The Dust Bowl shows that farmland must be planned carefully if it is to support single crop species that are not naturally adapted to the area. A different example comes from Yellowstone National Park. After people moved west, wolf populations dropped sharply. Prey animals such as pronghorn and mule deer increased, and they ate young Aspen saplings. Aspen trees declined, which led to more erosion and less habitat for birds and other animals.

Wolves were later reintroduced to Yellowstone, and the Aspen population has since shown a rebound. If this pattern is truly caused by the return of wolves, it supports the idea that apex predators help keep ecosystems balanced. Biodiversity also matters because it helps preserve stable ecosystems, supports more predictable weather patterns, and keeps raw material available for new industrial and medical products.

How Humans Change Biodiversity

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global climate change

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what is biodiversity?

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threats to biodiversity

Human activity is changing biodiversity and pushing Earth toward a sixth extinction event. Earlier mass extinctions ended many species, and then new species spread into the changed environment. Today, the Holocene epoch is seeing a mass extinction linked to human actions, and it is often called the Anthropocene. Human numbers and human biomass show how large this impact has become. In 2019, the human population reached 7.7 billion and is projected to rise to 10 billion by 2060. By biomass,...

conservation of declining populations

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biodiversity and human values

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what is conservation biology?

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what is climate?

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sustainable development

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habitat fragmentation

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key terms and concepts

Learn how human population growth, habitat loss, over-farming, and carbon emissions affect biodiversity. Includes the Dust Bowl and Yellowstone wolf example.

How Humans Change Biodiversity | JoVE K12

JoVE Core series brings biology to life through over 300 concise and easy-to-understand animated video lessons that explain key concepts in biology, plus more than 150 scientist-in-action videos that show actual research experiments conducted in today’s laboratories.

biology

JoVE Core Biología da vida a la biología a través de una serie con más de 300 lecciones de vídeo animadas, concisas y fáciles de entender, que explican conceptos clave de la biología, incluyendo también más de 150 vídeos de científicos en acción, que muestran experimentos reales realizados en laboratorios actuales de investigación.

How Humans Change Biodiversity

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