1 The training course is five weeks. 2  During the first two weeks, students are in the classroom. 3  During the second three weeks, students complete a clinical externship at various Intermountain Healthcare hospitals.
But surprisingly, we still donât know how many species live by the shore: estimates vary widely, from 178,000 species to more than 10 million. NaGISA scientists pulled on their boots and waded and dived in coastal waters around the world to estimate the number of species on our coasts more precisely.
Every time we pass another population milestone â at the moment, weâre tallying a whole-Earth total of 7 billion â the question arises: How many people have ever lived on the planet? The Population Reference Bureau, or PRB, has an answer for that. (Make your guess now; the answer will appear lower down.) But itâs heavily qualified, and thereâs a story behind it. The story starts sometime in the 1970s, when a notion came into common conversation that the population was growing so fast that 75 percent of the people who had ever lived on Earth were currently alive.