BILD 3 Lecture Notes - Lecture 21: Survivorship Curve, Semelparity And Iteroparity, Bild

1. Life expectancies differ across populations. Life expectancy at birth in the U.S. is currently around 78 years (76 for males; 81 for females). Consider a population in which life expectancy at birth is 50. Given what you know about life history theory, discuss how this population would differ from the U.S. across the following life history characteristics: age at first marriage, age at first reproduction, total fertility (number of children born per female), length of time spent in school, and money spent on education. Be sure to support your predictions using life history theory.

2. The following data on interbirth interval (time between births), child survivorship, and percent of children married were collected to evaluate reproductive decisions within a population. Assuming a woman of this population has a 20-year reproductive span (maximum time available from first to last birth), use these data to 1) calculate the maximum number of live births a woman could have, and 2) determine the number of births that will lead to the highest fitness (surviving children who marry) if we assume that all married children will have the same number of offspring. To receive credit, you must show your work. Lastly, what are the implications of your results?

% child %

IBI (months) Survivorship ever married

Populations (Ecology)

•What’s the difference between a cohort and static life table and what are the difficulties with each? Be able to interpret data in a life table.

• Be able to draw or interpret survivorship curves for different populations. What are the differences between the three types?

• Why does population age structure matter?

• What happened to Pablo Escobar’s hippos? What are some possible consequences? What might happen in the future?

• What are exponential and geometric growth?

• Be able to graph population size over time for a given growth rate (like figure 10.11).

• What’s the difference between density dependent and density independent factors to limit growth? Give examples. Which one regulates population size? Why?

• What is logistic growth? Explain how the growth rate changes at different population sizes. Be able to compare logistic and exponential growth.

• What are the four factors that affect population size over time?

• What are population cycles? What are some of the factors that drive them?

• What is delayed density dependence and why does delayed density dependence cause populations to fluctuate? What factors affect these fluctuations? Be able to draw typical population fluctuation figures like fig. 11.10.

• What’s the difference between stabilizing and destabilizing feedbacks? How do delayed feedbacks affect a stabilizing feedback?

• How does population size affect the likelihood of extinction?

• What is the Allee effect? How does it affect growth rate at different population densities? Draw a figure illustrating this.

PLEASE ANSWER IN PARAGRAPH FORM CORRECTLY. I appreciate it.

1. A) Describe what SexualSelection is and B) explain how it differs fromNatural Selection

2. Research a behavior in an animal andA) explain the ultimate causes of that behaviorand B) list the proximate causes of it.

3. “The southern gastric broodingfrog was discovered in 1972 and properly described in 1981. Intenseinterest followed and in the same year it had disappeared in thewild, shortly followed by the last captive specimen's death in1983. The interest was primarily due to the frog's unusualreproductive method. The female swallows her eggs and turns herstomach into a womb, vomiting up her young when they are grown. Theloss of her stomach means she doesn't eat while they develop, andher new womb bloats so much it causes her lungs to collapse(meaning she has to breathe through her skin). On the other handanother species of frog, the Túngara frog, lay their eggs in a pondand leaves them to develop on their own without any parental care”(www.facebook.com/evolutionarybiology - like). A)Compare the gastric brooding frog and the Túngara in terms of howthey balance the trade-off of quality vs. quantity of offspring(are they each K-selected or r-selected?). B) Whatother life-history traits (include: life span, number of offspringproduced, age at reproduction, reproductive events per lifetime) doyou expect to find differences between gastric brooding frog or theTúngara frog? Explain.

4. A) Explain why one can argue that humanswere K-selected species before the industrial revolution and now inmodern times see to be r-selected (in your explanation include theterms: carrying capacity, rate of population growth).B) However, in developed countries, the number ofoffspring produced per couple is decreasing every year, the age offirst time mothers in increasing (they are older when they havetheir first baby) and the cost of investment per offspring isincreasing (for example college tuition!). Explain what effectwould that have in the model of population growth in developedcountries (do you expect them to be more K-selected or r-selected?)Make sure to support your argument. C)Can human population increase forever? (use the terms: carryingcapacity, population growth, density-dependent anddensity-independent factors).

5. Study the figure below (published in Kwanoet al. 2002). The x-axis of the figure shows different locations atdifferent altitudes, with altitude decreasing from left to right(W. Java has the highest altitude, W. Mindanao has the lowest). They-axis represents the range of body length for beetles found ateach location. Two species of closely related rhinoceros beetlesinhabit Southeast Asia: Chalcosoma caucasus andChalcosoma atlas. One species, C. atlas (whiteboxes in the figure), is more common in low altitude, while C.caucasus (filled boxes in the figure) is more common in higheraltitudes. However, they overlap at intermediate altitude (fromLampung to E. Thailand). The graph shows the body length of eachspecies in allopatric and sympatric locations. What ecologicalphenomenon can explain the differences between the allopatric (whenonly one species lives in that location) and sympatric (when bothspecies live in the same location) populations? Please explain yourargument, you MUST include the terms: competition, competitiveexclusion, realized niche, fundamental niche, resource-partitioning& character displacement).