Microbes
Explainer: Virus variants and strains
When viruses become more infectious or better able to survive the body’s immune system, they become a type of variant known as a strain.
By Janet Raloff
MS-LS4-6
Use mathematical representations to support explanations of how natural selection may lead to increases and decreases of specific traits in populations over time.
More Stories in MS-LS4-6
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FossilsDinosaur families appear to have lived in the Arctic year-round
Fossils of baby dinosaurs in northern Alaska challenge the idea that northern dinosaurs only spent their summers in the high Arctic.
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ArchaeologyFossils unearthed in Israel reveal possible new human ancestor
They come from a previously unknown Stone Age group that may represent a complex mashup of early members of our genus Homo.
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Health & MedicineWill we all need COVID-19 booster shots?
Experts say not yet, but booster vaccines may be coming as new SARS-CoV-2 virus variants keep emerging.
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LifeLet’s learn about dogs
From learning the names of their toys to sniffing out viruses in human sweat, dogs are far more than household pets.
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AnimalsScience and Indigenous history team up to help spirit bears
When scientists and Indigenous people work together, their efforts can benefit bears and people.
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Tiny spider uses silk to lift prey 50 times its own weight
Dropping the right silk let’s a spider haul mice, lizards and other giants up off the ground.
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ArchaeologyHarsh Ice Age winters may have helped turn wolves into dogs
In the Ice Age, Arctic hunters may have turned to some game for their fatty bones. Much of those animals’ meat might have been left to domesticate dogs.
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ArchaeologyThis prehistoric woman from Peru hunted big game
Women in the Americas speared large prey as early as 9,000 years ago, new archaeological evidence suggests.
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GeneticsScientists Say: Evolution
Evolution is how species change over time. Individuals in the group vary, and some will pass on their genes. Over time, the whole species changes.