2. Ecology: Population Ecology

3. 2 POPULATIONS 3. A population is a group of individuals of the same species living in an area

4. DISTRIBUTION PATTERNS Uniform distribution results from intense competition or antagonism between individuals. Random distribution occurs when there is no competition, antagonism, or tendency to aggregate. Clumping is the most common distribution because environmental conditions are seldom uniform. 3 Populations disperse in a variety of ways that are influenced by environmental and social factors

5. Fig. 52.1, Campbell & Reece, 6 th ed. Clumped distribution in species acts as a mechanism against predation as well as an efficient mechanism to trap or corner prey. It has been shown that larger packs of animals tend to have a greater number of successful kills. What causes these populations of different organisms to clump together?

6. POPULATION DISPERSAL In rare cases, long-distance dispersal can lead to adaptive radiation For example, Hawaiian silverswords are a diverse group descended from an ancestral North American tarweed 5

7. THE SPREAD OF THE AFRICANIZED HONEY BEE WHEN DID THEY FIRST ARRIVE IN THE AMERICAS? HOW LONG DID IT TAKE FOR THEM TO EXPAND THEIR RANGE INTO THE US? HOW CAN YOU EXPLAIN THEIR SUCCESS IN EXPANDING THEIR TERRITORY? 6

8. SMALL GEOGRAPHIC RANGE 7

9. SPECIES WITH A LARGE GEOGRAPHIC RANGE 8

10. 9 ESTIMATING POPULATION SIZE THE MARK-AND-RECAPTURE TECHNIQUE 1. 2. 3.

11. ESTIMATING POPULATION SIZE THE MARK-AND-RECAPTURE TECHNIQUE 10

12. LET’S TRY AN EXAMPLE! 11

13. 12

14. 13 WHICH METHOD WOULD YOU USE? 1. To determine the number of deer in the state of Virginia? 2. To determine the number of turkeys in a county? 3. To determine the number of dogs in your neighborhood? 4. To determine the number of ferrel cats in your neighborhood?

15. SURVIVORSHIP CURVES What do these graphs indicate regarding species survival rate & strategy? 025 1000 100 Human (type I) Hydra (type II) Oyster (type III) 10 1 50 Percent of maximum life span 10075 Survival per thousand I.High death rate in post-reproductive years II.Constant mortality rate throughout life span III.Very high early mortality but the few survivors then live long (stay reproductive)

16. POPULATION GROWTH CURVES 15 d = delta or change N = population Size t = time B = birth rate D =death rate

17. POPULATION GROWTH MODELS

18. EXPONENTIAL GROWTH CURVES 17 d = delta or change N = Population Size t = time r max = maximum per capita growth rate of population Population Size, N Time (hours) Growth Rate of E. coli

19. LOGISTIC GROWTH CURVES 18

20. LOGISTIC GROWTH CURVES 19 d = delta or change N = Population Size t = time K =carrying capacity r max = maximum per capita growth rate of population

21. COMPARISON OF GROWTH CURVES 20

22. GROWTH CURVE RELATIONSHIP 21

23. EXAMINING LOGISTIC POPULATION GROWTH 22

24. EXAMINING LOGISTIC POPULATION GROWTH 23 Hypothetical Example of Logistic Growth Curve K = 1,000 & r max = 0.05 per Individual per Year

25. POPULATION REPRODUCTIVE STRATEGIES r-selected (opportunistic) Short maturation & lifespan Many (small) offspring; usually 1 (early) reproduction; No parental care High death rate K-selected (equilibrial) Long maturation & lifespan Few (large) offspring; usually several (late) reproductions Extensive parental care Low death rate

26. 25 Some populations overshoot K before settling down to a relatively stable density Some populations fluctuate greatly and make it difficult to define K How Well Do These Organisms Fit the Logistic Growth Model?

27. Percent of population Rapid growth Afghanistan Slow growth United States No growth Italy Male Female Age 85+ 80–84 75–79 70–74 65–69 60–64 55–59 50–54 45–49 40–44 35–39 30–34 25–29 20–24 15–19 10–14 5–9 0–4 Age 85+ 80–84 75–79 70–74 65–69 60–64 55–59 50–54 45–49 40–44 35–39 30–34 25–29 20–24 15–19 10–14 5–9 0–4 100 88888866666644444422222200 Age Structure Diagrams: Always Examine The Base Before Making Predictions About The Future Of The Population