Mastering Biology Practice Test

Type I survivorship curves reflect species that invest in relatively few offspring and provide care, so most individuals survive through the early and middle years and deaths occur mainly later in life. This results in low juvenile mortality and many individuals living to old age, with mortality increasing as aging progresses. Humans and many large mammals are classic examples. Therefore, the general pattern is low juvenile mortality and most individuals surviving to old age. If juveniles were highly vulnerable, you'd see a Type III pattern; if mortality were roughly constant across ages, that would be a Type II pattern.