BIOL 1050 Lecture 27 Outline of Last LectureI. Organismal EcologyII. Population EcologyOutline of Current LectureI. Population EcologyII. Human Population Growth Current LectureI. Population Ecologya. Logistic growthi. Logistic growth describes population growth that is gradually reduced as the population nears the environments carrying capacity b. Density-independent factors limit population sizei. Include natural disasters such as floods, earthquakes, and firesii. In an environment in which a “bad luck” event repeatedly occurs, a population can be in a perpetual state of exponential growt w ith periodic massive mortality events II. Human population growth a. Exponential growth (what the human population is in) i. Current birth rates exceed death rates by so much that we add 80 million people to the world population each yearb. To determine if population will continue to grow you have to know how many people are past, before or in the prime ages to reproducec. An age pyramid shows the number of individuals in each age group i. Norway1. Rectangular shape2. Similar number of young and middle-aged3. Stable population4. Industrialized countries, such as Norway, have age pyramids that appear more rectangular in shape, due to low birth rates and low death rates in older individualsii. Kenya1. Pyramid shaped2. More young than middle agedThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.3. Growing population, even if birth rates drop4. Developing countries such as Kenya, have age pyramids that pear triangular in shape due to high birthdates and high death rates in older individualsd. Growth rates have slowed, but unclear where human population numbers will peak i. Earth’s carrying capacity for humans is unknownii. Not clear if resources will support our peak population sizee. Human population crashi. 1700’s-human population on Easter Island outgrew its resources and crashedf. Limitless carrying capacityi. One reason that the carrying capacity for the human population is difficult to estimate is that we can increase it in a variety of ways1. Expanding into new habitats2. Increasing the agricultural productivity of the land3. Finding ways to live at higher
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