Fossils
Sudden shark die-off 19 million years ago eliminated most species
New fossil evidence shows 90 percent of sharks died in the mysterious event.
HS-LS2-4
Use a mathematical representation to support claims for the cycling of matter and flow of energy among organisms in an ecosystem.
More Stories in HS-LS2-4
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AgricultureSoil (and its inhabitants) by the numbers
Teeming with life, soils have more going on than most of us realize.
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EnvironmentWhat you can do to improve soils
Soils are the life-sustaining structures under our feet. Here are some tips for keeping soils healthy. First rule of thumb: Give more than you take.
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EnvironmentJumping ‘snake worms’ are invading U.S. forests
These bad-news invaders are spreading across the United States. As they turn forest debris into bare ground, soils and ecosystems are changing.
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PlantsThe faster trees grow, the younger they die
As climate change spurs forest tree growth, it also shortens trees’ lives. That results in a quicker release of climate-warming carbon back into the atmosphere.
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AnimalsWhales get a second life as deep-sea buffets
When a whale dies and sinks to the seafloor, it becomes a feast for hundreds of different types of creatures.
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A dirty and growing problem: Too few toilets
As the famous book says, everybody poops. That’s 7.8 billion people, worldwide. For the 2.4 billion with no toilet, the process can be complicated.
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EnvironmentGreener than burial? Turning human bodies into worm food
Composting human bodies yielded good results — and good soil — in one small study. It could become an alternative to burial or cremation in one state.
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OceansSmall swimmers may play huge role in churning the seas
Hoards of migrating shrimp and krill can cause large-scale water movements in the ocean, a new study suggests.
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ClimateAnalyze This: Climate change could make food less healthy
Levels of important nutrients are lower in crops exposed to high levels of carbon dioxide, a greenhouse gas. How high? Try levels expected to be typical 30 years from now.