November 3, 2015 – NEED TEXTBOOK TODAY

1. November 3, 2015– NEED TEXTBOOK TODAY Agenda: • YellowStone and Wolves Video • Review Ch 52 Synthesis Ques. • Ch 53 Population Eco Notes – Lecture and Independent Notes • Survivorship Curve Practice Homework: Finish Ch 53 Notes, Start Ch 54 Vocabulary (Some From Project)

2. Synthesis Worksheet 4 a. DEATH… Less tilt would cause LESS seasons… warm… longer days…. 4 b. Biomes – Less diversity of species, extinction, adapt Less tundra and forests More deserts and grasslands

3. Chapter 53 Population Ecology

4. Overview: Earth’s Fluctuating Populations How density, dispersion, and demographics can describe a population. The differences between exponential and logistic models of population growth. How density-dependent and density-independent factors can control population growth.

5. Population ecology is the study of populations in relation to environment Including environmental influences on population density and distribution, age structure, and variations in population size

6. Concept 52.1: Dynamic biological processes influence population density, dispersion, and demography Births and immigration add individuals to a population. Births Immigration PopuIationsize Emigration Deaths Deaths and emigration remove individuals from a population. Growth Rate = (Birth + Immigration) – (Death + Emigration)

7. What methods could you use to determine population density and distribution?

8. Determining population size and density: • Count every individual • Random sampling • Mark-recapture method (Will practice in class)

9. Sample Mark and Recapture Scenario To measure the population density of chipmunks in a particular park, you sample several plots and capture 50 chipmunks. You mark each of their backs with a small red dot of paint. The next day, you capture another 50 chipmunks. Among the 50, you find 10 that are marked. # of recaptures on day 2 = # marked in first catch Total # caught on day 2 Total population N 10 = 50 N = 250 Chipmunks 50 N What are potential problems that could arise from this method? What would your solution be to fix them?

10. Environmental and social factors influence the spacing of individuals in a population Patterns of Dispersion • Clumped: • Is one in which individuals aggregate in patches • May be influenced by resource availability and behavior • Uniform • Is one in which individuals are evenly distributed • May be influenced by social interactions such as territoriality • Random • Is one in which the position of each individual is independent of other individuals

11. Life table : age-specific summary of the survival pattern of a population Demography: the study of vital statistics that affect population size

12. Survivorship Curve: represent # individuals alive at each age • Type I: low death rate early in life (humans) • Type II: constant death rate over lifespan (squirrels) • Type III: high death rate early in life (oysters)

13. Concept 52.2: Life history traits are products of natural selection Natural selection favors traits that will improve an organism’s survival and reproductive success. The traits that affect an organism’s schedule of reproduction and survival make up its lifehistory. Life history includes: When reproduction begins, How often an organism reproduces, and how many offspring are produced each time

14. Species that exhibit semelparity, or “big-bang” reproduction Reproduce a single time and die Agave • Species that exhibit iteroparity, or repeated reproduction • Produce offspring repeatedly over time

15. Organisms have finite resources Researchers in the Netherlands studied the effects of parental caregiving in European kestrels over 5 years. The researchers transferred chicks among nests to produce reduced broods (three or four chicks), normal broods (five or six), and enlarged broods (seven or eight). They then measured the percentage of male and female parent birds that survived the following winter. (Both males and females provide care for chicks.) 100 80 Male 60 Female Parents surviving the following winter (%) 40 20 0 The lower survival rates of kestrels with larger broods indicate that caring for more offspring negatively affects survival of the parents. CONCLUSION Reduced brood size Normal brood size Enlarged brood size “Trade-offs” between survival and reproduction

16. Consider two rivers: one is spring fed and is constant in water volume and temperature year round; the other drains a desert landscape and floods and dries out at unpredictable intervals. Which is more likely to support many species of iteroparous animals? Why? Did you get it?

17. Homework: Life History and Survivorship Curve PracticeNotes: All starred questions covered in class. Complete all non-starred items. Ch 53Chapter 54 Vocabulary

19. November 4, 2015 • Review the Last of Population Notes Ch 53 • Weekend HW: • Population Ecology Practice Problems • Inquiry Workbook Article 4 on Prairie Ckns • Finish Ch 54/55 Notes • Work on Project

20. Warm-Up: How well do we understand the homework? A type I survivorship curve is level at first, with a rapid increase in mortality in old age. The type of curve is • Typical of many invertebrates that produce large numbers of offspring • Typical of large mammals • Found most often in r-selected populations with a rapid rate of reproduction • Almost never found in nature

21. Types of Population GrowthAge Structure Pyramids (Congo) Potential, ^ Youth: High birth rate, stable reproductive age (Italy) Low birth rate, old age structure, migration (USA) Slow growing: Declining fertility and mortality rates, Baby boomers Zero population growth - birth rate equals the death rate

22. Population Growth Models

23. Concept 52.3: The exponential model describes population growth in an idealized, unlimited environment. The rate of reproduction is at its maximum, called the intrinsic rate of increase or rmax) Though the rate is constant, the population increases exponentially due to the accumulation of new individuals per unit of time. Shown in a J-Curve (next slide) dN = rmaxN dt Exponential Population Growth Rate dN = popu. size at given time dt = time Rmax = max rate N = popu size Assumes unlimited resources.

24. Exponential population growth Results in a J-shaped curve 8,000 6,000 Elephant population 4,000 2,000 0 1900 1920 1940 1960 1980 Year Can indicate rebounding population. If resources are infinite, what types of species are capable of exponential growth?

25. Exponential Growth Problem Socrative - Sample Problem: A certain population of mice is growing exponentially. The growth rate of the population (r) is 1.3 and the current population size (N) is 2,500 individuals. How many mice were added to the population the following year?

26. Where is exponential growth in a plant population more likely: on a newly formed volcanic island or in a mature, undisturbed rain forest? Why? In 2006, the USA had a population of about 300 million people. If there were 14 births and 8 deaths per 1,000 people – What was the country’s net population growth that year? (Ignore immigration and emigration.) Did you get it? – Socrative Questions

27. Concept 52.4: The logistic growth model includes the concept of carrying capacity Exponential growth cannot be sustained for long in any population Logistic Growth Model A more realistic population model Limits growth by incorporating carrying capacity Maximum population size the environment can support

28. The per capita rate of increase declines as carrying capacity is reached We construct the logistic model by starting with the exponential model And adding an expression that reduces the per capita rate of increase as N increases Maximum Per capita rate of increase (r) Positive N  K 0 Negative Population size (N) The Logistic Growth Model K = Carrying capacity

29. The logistic model of population growth Produces a sigmoid (S-shaped) curve 2,000 dN 1,000  1.0N Exponential growth dt 1,500 800 K  1,500 600 Logistic growth Number of Paramecium/ml Population size (N) 400 1,000 dN 1,500  N  1.0N dt 1,500 200 0 0 5 15 10 500 Time (days) 0 0 5 10 15 Number of generations Figure 52.12

30. Some populations overshoot K Before settling down to a relatively stable density 180 150 120 90 Number of Daphnia/50 ml 60 30 0 160 0 40 60 100 120 140 20 80 Time (days) A Daphnia population in the lab. The growth of a population of Daphnia in a small laboratory culture (black dots) does not correspond well to the logistic model (red curve). This population overshoots the carrying capacity of its artificial environment and then settles down to an approximately stable population size. Figure 52.13b

31. Some populations fluctuate greatly around K 80 60 40 Number offemales 20 0 1995 2000 1980 1985 1990 1975 Time (years) A song sparrowpopulation in its natural habitat. The population of female song sparrows nesting on Mandarte Island, British Columbia, is periodically reduced by severe winter weather, and population growth is not well described by the logistic model. Figure 52.13c

32. Did you get it?

33. Explain why a population that fits the logistic growth model increases more rapidly at intermediate size than at relatively small or large sizes. Describe what happens to a population as N approaches K according to the logistic equation. Did you get it?

34. What environmental factors stop a population from growing? Why do some populations show radical fluctuations in size over time, while others remain stable? Connecting favorable traits and densities of populations.

35. Evolution: Reproductive Strategies

37. Factors that limit population growth: • Density-Dependent factors: population matters • i.e. Predation, disease, competition, territoriality, waste accumulation, physiological factors • Density-Independent factors: population not a factor • i.e. Natural disasters: fire, flood, weather

38. Cheetahs are highly territorial • Using chemical communication to warn other cheetahs of their boundaries Factors that regulate populations • Oceanic Birds: Exhibit territoriality in nesting behavior

39. Density can influence the health and survival of organisms In dense population pathogens can spread more rapidly Health/Disease Predation As a prey population builds up, predators may feed preferentially on that species

40. The accumulation of toxic wastes can contribute to density-dependent regulation of population size Toxic Wastes Intrinsic Factors (Physiological) Increased population density: Hormone Fluctuations Weaken Immunity Sexual organs shrink Stress Ex. of negative feedback mechanisms

41. Researchers regularly surveyed the population of moose on Isle Royale, Michigan, from 1960 to 2003. During that time, the lake never froze over, and so the moose population was isolated from the effects of immigration and emigration. FIELD STUDY RESULTS Over 43 years, this population experienced two significant increases and collapses, as well as several less severe fluctuations in size. 2,500 Steady decline probably caused largely by wolf predation 2,000 1,500 Moose population size 1,000 Dramatic collapse caused by severe winter weather and food shortage, leading to starvation of more than 75% of the population 500 0 2000 1970 1980 1990 1960 Year The pattern of population dynamics observed in this isolated population indicates that various biotic and abiotic factors can result in dramatic fluctuations over time in a moose population. CONCLUSION Figure 52.18 Population Dynamics: A dance of biotic and abiotic factors

42. What do you notice about the population cycles of the showshoe hare and lynx?

43. Concept 52.6 Human population growth has slowed after centuries of exponential increase Current Human Population Growth No population can grow indefinitely and humans are no exception Global Carrying Capacity Ecological Footprint Concepts to Review Independently

44. Did you get it? HANDOUT