Crerari stellarus is an annual, semelparous, extinct, marine mammal (extend disbelief, have fun with it). It lived about 250 million years ago (mya) and lived for only a single year and reproduced and then promptly died. Recent research in the dead sea has recovered stratified layers of bones. Dr. Crerar and undergraduates from George Mason University were able to extract the DNA from these specimens and determine which belonged to C. stellarus. The dredging was complete, enabling us to estimate their population sizes at 249 (Nt) and 250 mya (Nt+1). These populations were 134 and 251, respectively.

You should be able to calculate the net replacement rate R (the ratio of Nt+1/Nt) and to project the population size of this extinct, marine, mammal had it not gone extinct abruptly. Finally, you should calculate how long it would have taken for the population to have grown to 500 individuals. Can you answer these questions?

Sub-question 1What is the net replacement rate, R, for this population?

Sub-question 2What size will the population be 2 years after its initial population size (Nt) assuming the population continued to grow at the same rate?

Sub-question 3How large would the population had been after 7 years?

Sub-question 4How large would the population had been after 11 years?

Sub-question 5 How long would it have taken for the population to reach 500?