1. Introduction to Populations
Survivorship Curves & Reproductive Strategies

2. Population Dynamics Why study?
Study of how populations change in size, density, and age distribution in response to changes in environmental conditions
Why study?
Conservation
Management
Understand environmental changes and effects
Predict future patterns

3. Factors that determine population size
Births, deaths, immigration, emigration
( N) = [B+ I] – [D+ E]
Growth rate (r) = ___N_ N0

4. Exponential Growth Rate
Population grows faster as population increases
Lag phase, acceleration phase
Yields J-shaped growth curve
Nt = N0ert
e = 2.71 (mathematical constant)

5. Logistic Growth Rate
Involves exponential growth rate followed by steady decrease in growth with time
Population levels off at carrying capacity (K)
Yields S-shaped curve

6. Reproductive Strategies

7. Reproductive strategies
Trait
K-selected species
r-selected species
Life span
Long
Short
Reproductive age
Late
Early
# reproductive events
Few
Many
# offspring
Parental care
High
Low
Size of offspring
Large
Small
Population growth rate
Slow
Fast
Population dynamics
Stable, near K
Highly variable, below K

8. K-selected r-selected

9. Survivorship Curves