Elephant seals were hunted nearly to extinction in the 1800s. All current northern elephant seals descend from about 20 individuals, and now they have very little genetic variation.

Five birds accidentally get trapped in a shipping container and are transported to a new continent. Their descendants look and behave differently than the original population.

In a desert, lizards that blend in with the sand survive more often. Over time, fewer bright green lizards are born.

In industrial England, dark-colored moths became more common due to pollution blackening tree bark, giving dark moths better camouflage.

Island Foxes on California’s Channel Islands have several islands that were colonized by small groups that migrated to them and have unique traits on each island

Some bromeliads (Neotropical plants) colonize isolated tree islands in flooded forests. Each small population shows slightly different flower colors due to limited gene flow and random allele changes over time.

Modern Icelanders are genetically very similar, with many traits traceable to original Viking settlers.

In regions with high malaria, individuals with one sickle cell allele are more likely to survive malaria. Over time, this trait became more common in those populations.

In Central America, forest fragmentation drastically reduced glass frog populations in some regions. These small, isolated populations now show less genetic diversity than others.

In a lizard population, those with longer legs can run faster and escape predators. Over time, long-legged lizards become more common.

In Nevada, isolated desert tortoise populations became genetically distinct simply because of distance and a lack of movement between regions—no environmental pressure, just separation.

Hunters over-harvest a fish population, leaving just a few fish with rare striping patterns. Now, most of that species has stripes.

During El Niño events, food becomes scarce and smaller-bodied marine iguanas tend to survive better than larger ones, leading to a noticeable shift in body size in following generations.