Adaptations Traits that help organisms meet their basic needs and survive in their surroundings are called adaptations. Tools A B structural adaptations an adaptation of an organism's body parts or coloring mimicry an adaptation in which one species resembles another behavioral adaptation an inherited behavior that helps an organism survive fossil any remains or trace of an organism that was once alive mold a fossil that is a hollow place shaped like an organism cast fossil formed by sediments filling up a mold petrified fossil a fossil formed when minerals slowly replaces some or all of an organism, turning it to stone mutation changes in gene that may produce new traits