Question

Large number of eggs are produced by a spider species but due to little parental care, only a few of them reach adulthood. The line representing the survivorship curve for this species is

• A. Curve 1
• B. Curve 2
• C. Curve 3
• D. Curves 1 and 2
• E. Curves 1 and 3

Answer 1

The correct option is C Curve 3

Survivorship curves are the visual representation of demographic details. This curve is a graphical representation showing the survival pattern of organisms by plotting the number of individuals or organisms against age for a given species. There are three types of curves-
Type A is one which shows high age-specific survival probability with a rapid decline in survival in later life. These include ones with fewer numbers of offspring but with the larger investment in time and energy in parental care.
Type B shows cases a more or less constant mortality and survival rate irrespective of age.
Type C represents those with little or nil parental care and only a few reaching adulthood.
The case of spiders represented in the question shows the type 3 survivorship curve.
Thus, the correct answer is option C.