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Name Date Period HES: CHAPTER 8 Study Guide – POPULATION DYNAMICS, CARRYING CAPACITY, AND CONSERVATION BIOLOGY “We cannot command nature except by obeying her.” ~Sir Francis Bacon 8-1 Population Dynamics and Carrying Capacity 1. What are population dynamics? Biotic and abiotic factors that tend to increase or decrease the population size and age and sex make-up of a species 2. What are four (4) ways populations change in response to stress or changes in environmental conditions? size, density, dispersion, age distribution 3. What four (4) variables govern changes in population size? births, deaths, immigration, emigration 4. Write an equation showing how population change is related to births, deaths, immigration, and emigration. population change = (births+immigration) – (deaths+emigration) 5. What is the biotic potential of a population? the capacity for growth 6. What are four (4) characteristics of a population with a high intrinsic rate of increase (r)? reproduce early in life, have short generation times, can reproduce many times, have many offspring each time they reproduce 7. What is environmental resistance? all of the factors that limit the growth of a population 8. What is carrying capacity? the number of individuals of a given species that can be sustained indefinitely in a given space 9. How do biotic potential and environmental resistance interact to determine carrying capacity? biotic potential allows growth and environmental resistance limits how big a population can get – so these two factors together will determine how many individuals an area can support 10. List four (4) factors that can alter an area’s carrying capacity. light, water, space, nutrients, too many competitors or predators 11. Distinguish between exponential and logistic growth of a population. Give an example of each type. Exponential growth starts out slowly and then proceeds faster and faster as the population increases. Makes a j-shaped curve. Logistic growth involves exponential growth followed by a steady decrease in population growth until carrying capacity is reached. Makes a s-shaped curve. 12. How can a population overshoot its carrying capacity? What are the consequences of doing this? There is a reproductive time lag – the time needed for the birth rate to fall and the death rate to rise in response to resource overconsumption. 13. Distinguish between density-dependent and density-independent factors that affect a population’s size. Density-independent controls affect a population’s size regardless of its population density. Density-dependent controls have a greater impact as the population grows in density. 14. Determine if each of the following is density-dependent (DD) or density-independent (DI): a. b. c. d. e. f. g. h. i. j. DI DD DD DI DI DI DD DD DI DD flood bubonic plague competition for resources fire pesticide spraying clear cutting a forest disease predation hurricane parasitism 15. What are the four (4) types of population fluctuations? stable, irruptive, irregular, cyclic 16. Indicate what type of population fluctuation is being described below: a. irregular The population sizes of some species change irregularly for mostly unknown reasons. b. stable c. cyclic d. irruptive The population size of a species with a fairly unchanging population fluctuates slightly above and below its carrying capacity. The population undergoes sharp increases in size, followed by crashes over fairly regular time intervals. The populations of some species may occasionally explode to a high peak and then crash to a more stable lower level. 8-2 Connections: The Role of Predation in Controlling Population Size 17. Differentiate between the top-down control hypothesis and the bottom-up control hypothesis. Top-down: predators control prey populations Bottom-up: prey populations control predator populations 8-3 Reproductive Patterns and Survival 18. What are the two types of reproduction that can pass genes on to offspring? Asexual & sexual 19. Use the chart below to differentiate between the two types of reproduction. Asexual Reproduction All offspring are genetic copies of parent Common in single-celled species Sexual Reproduction Organisms produce offspring by combining gametes Offspring have combination of parents’ genes About 97% of known organisms reproduce this way 20. What are three (3) risks/problems associated with sexual reproduction? Females have to produce twice as many offspring to maintain the same number of young in the next generation as an asexually reproducing organism Increased chance of genetic errors when splitting and recombination of chromosomes Courtship & mating use energy, can transmit disease, & can inflict injury on males competing for mates 21. Why is sexual reproduction important? (give 2 reasons) Provides greater genetic diversity to offspring Males can gather food for young and females, and help protect and train offspring 22. What are the two (2) fundamental reproductive patterns? r-relected and k-selected 23. List the characteristics of the two patterns. r-Selected Example: bacteria, rodents, annual plants Many small offspring Little of no parental care Early reproductive age High population growth rate k-Selected Example: elephants, whales, humans, birds of prey, long-lived plants Fewer, larger offspring High parental care Later reproductive age Lower population growth rate 24. What does a survivorship curve show/represent? The # of survivors of each age group for a particular species