What scientist incorrectly thought that evolution could be explained by the inheritance of acquied t

Jean-Baptiste Lamarck. It means that is an animal somehow altered its body structure during its lifetime, then the alterations would be passed onto its offspring.

Example: You lift weights and have a ton of muscles. When you have children, your child should be born with big muscles too.

It's called Lamarckism (also Lamarckian inheritance), after a French guy named Jean-Baptiste Lamarck.

Basically, it says things like, if I'm a good geologist, my kids will be good geologists.

More specifically to evolution, it explained things like --

(1)  A giraffe's neck got longer because each generation just stretched its neck out longer to reach the trees.  It wasn't genetic drift or natural selection or Darwinian evolution.  It was generations of stretching.

(2)  Basically the same thing for the Galapagos tortoise with those unusual shells that allow them to raise their necks.

Maybe you have an Olympic sprinter, gold-medalist in the 100m dash.  According to Lamarck, he's going to pass on good sprinting ability not because of genes, but because he worked at it and made himself faster before he had children.

If I'm a good basketball player not because of inherent genetic predisposition, but because I go outside and practice my 3-point shot everyday... I'll pass on being a good basketball player, and over 100 generations, all of my distant progeny will be running around the NBA.