Question

Zebra Musse Zebra mussel population growth in the Great Lakes is a growing concern. Zebra mussels are not native to North America, and due to their ability to rapidly multiply, they have been depleting the food sources for many of the native fish species in the Great Lakes. They are also associated many siant and teth causing toie lgal bloms, preventing sunlight and oxygen access to fish life in the lakes. Three years ago, a 5 km2 section of the Great Lakes was studied and approximately 89 000 zebra mussel colonies were found. Each colony produced 120 colonies over a three-year period. However, only 2% of the new colonies survived past the first year. Over the three years, there were 97 000 dead colonies that were washed ashore in the Great Lakes. Many of the zebra mussels attach themselves to hard surfaces, such as boats and trailers It was estimated that approximately 85 000 colonies attached themselves to boats and left the area. Many of these zebra mussels died, but some managed to hitchhike on boat equipment and enter other waterbodies. Negligible numbers of zebra mussels migrated from other lakes. Calculate the change in population size. 11. Show all your work and round your answer to the nearest whole number. Calculate the population growth rate. 12. Show all your work and express your answer using scientific notation rounded to two decimal places. Calculate the per capita growth rate, over the three years. Show all your work and express your answer as a value between 0 and 1 rounded to two decimal places. Calculate the population density at the end of the third year. 14. Show all your work and express your answer as a whole number. Use the following information to answer question 15. Sheldrick Elephant Orphanage In Kenya, the Sheldrick Elephant orphanage takes care of elephants that have lost their herd as a result of poaching. In 2012, the orphanage had a population size of 387 elephants. Over the next two years, they had 18 pregnant cows birth successfully. Three cows and their calves were lost due to complications with their pregnancies. They lost 14 more from sickness They found 57 elephants that required care and were able to release 12 into the wild. All of the elephants are kept in a 225 m x 175 m rectangular park. Calculate the following for this population. 15. Show all your work and express your answers using two significant digits. a. Population growth b. Growth rate Per capita growth rate c. d. Population density at i. beginning of the year ii. end of the year

Answer 1

5km³ contained 89000 zebra mussel colonies. Each colony produced 120 colonies. So number of colonies = 120*89000 = 10680*10^3. 2% of ths colonies survived. So total number of colonies survived = 213600. 97000 colonies died . 85000 attached themselves and left. So number of colonies left approx = 213600-85000 = 128600

Change in population size ∆N/∆t= birth+immigration - (death+emmigration) = 213600 + 0 - 97000 - 85000 = 31600

Growth rate dN/dT = (b-d)N = 10680000- 10563400 * 31600 = 3.6 * 10^9

Answer 2

12) dN=31600 therefore 31600/3 years = 10533.33. Expressed in scientific notation, gr would be 1.05 x 10^4

13) cgr= dN/iN therefore 31600/89000 = 0.36

14) Dp= N/A therefore take the final population (89000+31600) and divide by the 5 km. 120600/5 = 24120. 24120 colonies per km3