1. COUNTING POPULATIONS Estimations & Random Samples

2. What are the 3 biggest populations in this pond community? Name of Population DucksCattailsWater Lilies Actual Count Sample Count

3. ACTUAL COUNT Each member of a population is counted one by one Name of Population DucksCattailsWater Lilies Actual Count 6204 Sample Count

4. Which population was easiest to count? Why?

5. RANDOM SAMPLES Make a GRID Count the total number of squares in the grid Choose one square of the grid at random. Count the population in that one square. Estimate the total population by multiplying the number in one square times the total squares in the grid.

6. RANDOM SAMPLES Name of Population DucksCattailsWater Lilies Actual Count 6204 Sample Count 1 x10 = 103 x 10 = 301 x 10 = 10

7. ACCURACY??? Scientists help prevent over- and under-estimation by taking several samples and averaging the results.

8. QUESTIONS Why is a sample a good way to count a population? What are some disadvantages to using a sample? What could you do to sample a population of animals that do not stay in one place?

9. More on Ecological Statistics… Population Statistics Carrying Capacity: the maximum population size the environment can sustain indefinitely given food, habitat, water, and other necessities available in the environment

10. Types of growth ExponentialLinear

11. Population Growth Curve