Goodness no, they are completely different species! They even originated on different continents.
Sweet Potatoes and Yams are Very Different!
Sweet potatoes are roots of the species Ipomoea batatas and are native to Central/South America. The have tapered ends with thin, smooth skin and the flesh is usually (but not always) orange or reddish. They are of course sweet, with a moist, creamy texture when baked or roasted.
True yams are tubers from the genus Dioscorea and are native to Africa and Asia. They are cylindrical, can be very large, with thick, rough, bark-like brown skin and white, yellow, or rarely purple flesh. Yams are much more starchy and dry, with a mild, earthy, potato-like flavor and little sweetness.
They are not closely related to each other or to “regular” potatoes.
So-called Yams are Often Mis-labeled Sweet Potatoes
In the U.S., orange, soft sweet potatoes were historically marketed as “yams” to distinguish them from firmer, paler sweet potatoes, and that marketing term stuck. Today, most “yams” in U.S. supermarkets—including canned “yams”—are actually soft orange sweet potatoes. True yams are more often found in African, Caribbean, and some Asian markets, where they are boiled, fried, pounded, or stewed as a starchy staple.
