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

尽管生物多样性已经改变了 在整个地质时期， 因此上升和下降 地球历史上五次大规模灭绝。
 第六次大灭绝， 被称为现在的全新世灭绝， 可归因于人类活动。
 人口爆炸 是当前生物多样性丧失的核心 导致栖息地丧失， 过度开发，入侵物种的引进 以及全球气候变化。
 人类对食物和庇护所的 资源需求的大幅增加 导致了许多物种的栖息地丧失。
 毁林改造农业用地 将物种从其自然栖息地中驱逐出去 小而零碎的家庭范围 资源少生存挑战多。
 许多物种被用于食品和医药 被过度开发，超出了物种的恢复能力。
 这是由高经济需求引起的 这是物种的繁殖能力所 不能满足的。
 此外，入侵物种的引进， 导致生态系统发生剧烈变化， 通过捕食移除本地物种 以及资源竞争。
 没有天敌， 入侵物种导致生物多样性迅速下降。
 最后，全球二氧化碳 和其他温室气体排放量的增加 导致了增量增长 在全球平均温度下。
 这种效应减少了可居住空间的数量 对于许多物种 改变了迁徙 以及其他季节性活动模式。

麦克莱曼、罗伯特 A.、朱丽叶·杜普雷、莉亚·贝朗·福特、詹姆斯·福特、康拉德·加耶夫斯基和格雷戈里·马希尔顿。"我们从沙尘暴中学到了什么:科学、政策和适应的教训。"人口与环境 35，第 4 期（2014 年 6 月 1 日）:417-40。[<a href="https://doi.org/10.1007/s11111-013-0190-z" target="__blank">来源</a>]

Dobson， Andy P. "黄石狼和构建自然系统的力量"。PLoS 生物学 12，第 12 期（2014 年 12 月 23 日）。[<a href="https://doi.org/10.1371/journal.pbio.1002025" target="__blank">来源</a>]

Bar-On、Yinon M.、Rob Phillips 和 Ron Milo。"地球上的生物量分布。"美国国家科学院院刊 115，第 25 期（2018 年 6 月 19 日）:6506。[<a href="https://doi.org/10.1073/pnas.1711842115" target="__blank">来源</a>]

对生物多样性的威胁

在整个地质历史中发生了五次大灭绝事件，导致生物多样性的消失，随后是适应新条件的物种的反弹。在当前的地质时代，那就是全新世，有第六次灭绝事件正在进行中。这种大规模灭绝归因于人类活动，因此被临时称为人类世代。到2019年，地球上的人口达到77亿人，到2060年预计将达到100亿。根据生物量（特定物种的实际质量）对人类的影响，人类占地球哺乳动物的36％，牲畜占60％，而野生哺乳动物只有4％。所有鸟类中约有70％是家禽，只有30％是野生鸟类。
为了尽量减少人类对生物多样性和气候的影响，我们必须了解我们的哪些活动是有问题的，并在人类文明和进步的需要与子孙后代的可持续计划之间取得平衡。生物多样性的一些主要威胁包括人类发展造成的生境丧失，过度耕作，以及来自工厂和车辆的二氧化碳排放量增加。
 
 案例研究
 
 一个关于人类对天气影响的案例研究可以在20世纪30年代的“沙尘暴”事件中找到。上世纪二三十年代，大批农民迁往大平原，开垦土地，将当地的地被植物移走，以便种植作物，这些作物的根系一般较浅。在一个以堪萨斯州和得克萨斯州北部为中心，向北延伸至加拿大，向南延伸至得克萨斯州的地区，极端干旱条件和考虑不周的耕作方式共同导致了沙尘暴，沙尘暴将沙砾一路堆积到东北部各州。最终，由于这些风暴和不幸的经济萧条，出现了普遍的粮食短缺，许多家庭不得不放弃他们的农场。显然，为了使土地能够支持不自然适应的单一植物物种，必须精心规划农场，以应对生物多样性的丧失。
 
 在美国黄石国家公园可以看到一个不那么激进的例子。在人类开始向西迁徙之后，狼的数量急剧减少。结果，叉角羚和骡鹿等被捕食动物的数量增加。因为这些动物往往吃年轻的白杨树苗，这导致白杨树的数量减少。树木流失的下游影响包括土地侵蚀加剧和鸟类和其它动物栖息地的丧失。对这一连串事件的支持来自于最近将狼重新引入黄石公园，这与公园中观察到的白杨种群反弹有关。如果这种相关性真的表明白杨是由于狼的重新引入而恢复活力的话，那么这项研究支持了一个普遍的概念，即顶端（顶端）捕食者对生态系统的生物多样性至关重要。
 
 维持生物多样性对于保持生态系统的平衡、延长可预测的天气模式以及保持研究新的工业和医疗产品的原材料至关重要。

在地球地质历史中，曾发生过五次重大的生物灭绝事件，导致生物多样性大幅减少，随后物种数量又出现反弹……

Education

教育

JoVE Core

生物学

Ecology

生态学

Biodiversity and Conservation

生物多样性与保护

KEY TERMS AND CONCEPTS

关键术语与概念

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

what is weather?

How Sunlight Shapes Daily Weather

Weather is the current state of the atmosphere at a specific time and place. It is temporary and changes from one location to another. Weather is shaped by the interaction of the sun, atmosphere, hydrosphere, and geosphere. Solar radiation reaches Earth and interacts with water and land. These surfaces release that energy as thermal radiation, or heat, which warms the air above them. Some of that heat escapes back into space, but some is trapped by atmospheric gases. This heat retention is...

global climate change

Ancient Clues to Climate Change

Ancient climate clues help scientists track global climate change. Paleoclimatology is the study of climate conditions in Earth’s past and the causes and effects behind them. By comparing recent climate patterns with older records, researchers can find strong evidence for human-caused warming. Earth’s climate has changed many times over its 4.5 billion year history. In the last 650,000 years, there have been seven cycles of glacial advance and retreat. The most recent ice age ended more than...

what is biodiversity?

Biodiversity Across Genes, Species, and Ecosystems

Biodiversity is the variety of living things at the genetic, species, and ecosystem levels. It includes not only how many kinds of organisms exist, but also how they are related and how they interact with the world around them. Species diversity spans the full evolutionary tree. It includes single-celled prokaryotes such as bacteria and archaea, as well as the eukaryotic kingdoms: plants, animals, fungi, and protists. About 1.75 million species have been identified so far, and scientists...

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

Saving Species Through Population Recovery

Conservation of declining populations focuses on detecting a population drop, finding its cause, and stopping further loss. The goal is to prevent extinction by using scientific methods to identify the agents behind the decline. Once the cause is known, conservation teams can remove, oppose, or neutralize it. A common step is to test possible causes with a small trial group. If the cause is confirmed, the remaining animals may be moved to an unaffected area. When the population is too small or...

biodiversity and human values

Biodiversity in Food, Tools, and Medicine

Biodiversity supports human life through food, tools, medicine, and many other needs. Changes in the variety of species can also change the environment. Those environmental shifts can alter weather patterns and affect human civilizations. People have depended on biodiversity for agriculture since early human history. Agriculture began when ancestral humans found species that were good sources of food. At least 11,000 years ago, people started selecting plant and animal species to raise on...

what is conservation biology?

Protecting Biodiversity in Conservation Biology

Conservation biology is the science of protecting biodiversity and keeping ecosystems healthy. It looks at how living things, habitats, and human needs are connected. The goal is to preserve biodiversity so ecosystems can continue to function well. Healthy ecosystems provide people with important natural resources. These include food, medicines, and building materials. Ecosystems also deliver key services, such as cleaning air and water. Evidence shows that these services depend on...

what is climate?

Climate Patterns and Earth’s Energy Balance

Climate describes the usual weather conditions in a place over a long period of time. The idea is simple: climate is what you expect, while weather is what you get. Climate is shaped by geographic factors such as latitude, terrain, and how close an area is to bodies of water. Weather and climate are related, but they work on different time scales. Weather is the state of the atmosphere at a specific time and place. Climate is the average pattern of weather over much longer periods. Because of...

sustainable development

Protecting Oceans for Sustainable Development

Sustainable development depends on protecting oceans while meeting human needs. As the human population grows and uses more resources, people must stay aware of the planet’s natural limits. The goal is to improve life now without taking away the resources future generations will need. Long-term sustainability depends on understanding how human actions affect ecological systems. Oceans are a major part of this balance. They provide food for people, produce much of the atmosphere’s oxygen, and...

conservation of small populations

Saving Small Populations with Genetic Diversity

Small populations can be hard to save because they often lose genetic diversity. When variation is low, a species has fewer traits that may help it adapt to climate change, competition from other species, or new diseases. That makes extinction more likely. Large populations usually have a better chance of surviving new stresses. They are more likely to include individuals with genetic variants that are helpful in changing conditions. Small populations are much less likely to contain this kind...

habitat fragmentation

How Fragmented Habitats Affect Wildlife

Habitat fragmentation breaks one continuous habitat into smaller, separate patches. Human land conversion is a major cause of this change, and slower geological shifts in the physical environment can also fragment habitats. The process usually follows the same stages: perforation, dissection, fragmentation, shrinkage, and attrition. Perforation and dissection often begin during land development. Perforation happens when undeveloped land is cleared for something like a home, and dissection...

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系列通过300多节动画视频课简明易懂地讲解生物学中的关键概念，以及150余段视频展示科学家在现代实验室开展实际研究实验，让生物学变得平易近人。

How Humans Change Biodiversity

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