1. Happy Wed!
9/8/2010
State which species of turtle nests in the greatest numbers on Jupiter Island.
(1 mk)
(b) Compare the distribution of nesting in the three species of turtle along the eastern coastline of Florida. (2 mks)

2. (a) loggerheads / Caretta caretta 1
(b) all three species nest over the same range of latitudes on the same beaches/areas; density of loggerheads is greatest and leatherbacks is lowest; similar relative densities/numbers on the different beaches / latitudes; all three had most nests on Jupiter; more loggerheads at northern end of range /(Do not accept answers giving around 28 (°N) / on Melbourne;) the range 26–28 or 26–30.) 2 max

3. I’ll CHECK your IB Journal on quiz day for 5.1 and 5.3

4. Don’t forget...
“Exercises” ?s as you read or after we’ve gone over in class
Make sure you GET IT
“Practice end of chapter— old exam ?s
Studying for quizzes/tests!

6. 5.3 Populations
5.3.1
Outline how population size is affected by natality, immigration, mortality and emigration.
5.3.2
Draw and label a graph showing a sigmoid (S-shaped) population growth curve.
5.3.3
Explain the reasons for the exponential growth phase, the plateau phase and the transitional phase between these two phases.
5.3.4
List three factors that set limits to population increase.

8. 5.3.1 Factors affecting pop size

9. 5.3.2 Pop growth curves MODEL
Change in pop size over time
Pop expanding into a habitat offering INITIAL LOW RESISTANCE or LOW LIMITING FACTORS
A-Exp = rapid pop growth rate
B-slowing but still high
C-plateau = pop remains stable w/time;
slight oscillations

12. 5.3.3 Phases of pop growth curve…details!
EXPONENTIAL PHASE
Low/reduced limiting factors
Pop expands exponentially into 2n where n= # of generations
natality + imm. > mortality + emigr.
Note that it does not mean that death/ emigration= 0 !!!

13. When do you observe exp. phase in nature?
Pop of germinating annual plants in new season Bacterial onset of infection Succession—any species’ pop entering previously uninhabited area

14. 5.3.3 TRANSITION PHASE Resources reduced, become limiting
Competition…not all survive
NATURAL SELECTION!
 lower rate of increase in pop

15. 5.3.3 POPULATION PLATEAU Pop remains constant over time/generations
Natality + imm = mortality + emig
Pop size determined by CARRYING CAPACITY of that time

16. What factors affect the rate of growth of a population?

17. What factors LIMIT pop growth of a species?

18. 5.3.4 Factors limiting pop growth
With unltd resources, pop would keep increasing…exponentially!
REALITY CHECK!
Environmental resistance limits it & determines carrying capacity
Shortage of food/prey
Predation, parasitism
Disease
Accumulation of waste
Shortage of space/territory

19. Food for Thought...