BIO 311D 2nd Edition Lecture 35 Outline of Last Lecture I. Introduction to population ecologyII. Population growth modelsIII. Population dispersion, survivorship, mortality Outline of Current Lecture I. Measuring population growthII. Population growth modelsIII. Human population growthIV. Index Card Questions Current LectureI. Measuring population growth A. Population dynamics – per capita rate of increase 1. ^N / ^T = (b+i) – (d+e)2. r = per capita rate of increase in number of individuals (can be negative) a. ^N/ ^T = bN –dN b. r= b-d B. In 2006, the United States 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?300 million/ 1000 multiply by 6 C. You are studying a population of beetles of size 3000. During a one-month period, you record 400 births and 150 deaths in this population. Estimate b, d and r for that month and project the population size after a second month. R= .08 [(400-150)/3000]3250 + 8% of 3250 II. Population Growth ModelsA. J-Shaped exponential growth (unrestricted growth)1. Elephant in Kenya – elephant was protected and population went straight up 2. r= growth rate greater r, accelerated growth3. Point of maximum growth: as far up as you can go B. S-Shaped logistic growth (restricted growth)1. Carrying capacity K is the maximum population size that a particular environment can support 2. The rate accelerates point ofmaximum growth the rate slowsdown C. In the following graph, which of theexpressions of the exponential growthequation should be increased for curve 1to become more like curve 2?1. ^N/ ^T make it steeper2. D move to the right 3. B move to the left 4. (b-d) D. C, E 4-8: barely maximum, notenough people for mating E. What causes these populationchanges? (Figs 52-18, 52-19)1. Mortality factorsa. Density-dependent- Predation b. Density- independent 2. Which of the following statements is an example of a density-independent effect?a. The number of nests in an area is limited to 70b. The incidence of malaria increases as population increasesc. A drought kills all the seedlings in an aread. Large aggregations of guppies attract predators III. Human Population Growth A. What has affected human population growth in the past? In the present? 1. Industrial revolution, agriculture, medicine 2. Mortality rates has decreased due to medical care3. Life expectancy rates increasing (depending where you are)B. Age Pyramids 1. Rapid growth: more kids, fewer older group2. Slow growth: baby boomers, bulges of greater birth rate3. Decrease C. Health rate, Medical care, water can cause change in population
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