1. B. CHANGES IN POPULATION SIZE
1. Population growth models

2. a. geometric growth for populations with fixed breeding times
eg. one breeding cycle per year
All of the penguins come ashore at the same time to breed. As some babies die, the population falls again until next breeding season

3. for populations that are constantly growing
b. exponential growth
for populations that are constantly growing
eg. Yeast
They do not have a breeding season they just divide when conditions are right.
However, this can’t go on for ever and so we get the next slide.

4. c. logistic growth rate
growth that levels off as the population grows towards its carrying capacity
carrying capacity – the maximum number of organisms that can be sustained by the available resources over a period of time

5. carrying capacity exceeding phase stationary phase log phase lag phase
pop
size
stationary phase
log phase
lag phase
time

6. lag phase – slow growth at start as get established
log phase – rapid growth when population is settled in new area
stationary phase – long term pattern fluctuates, but always below carrying capacity
exceeding phase – pass carrying capacity, damage environment and so pop is reduced

7. 2. affecting population change
births,
deaths,
emigration
& immigration
3. Types of populations
a. open population – all 4 factors affect population
b. closed population – no emigration or immigration to change the population

8. 4. percentage population change
[(births + immigration) – (deaths + emigration)] x 100
initial population size
pg 670 # 7 a and #5 a,b,c

9. Gulls & Terns pg 6