bio123 - BIOLOGY 1002 Chapter 26 1 Defne population...

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BIOLOGY 1002 Chapter 26: 1. Define population, ecosystem, community, and biosphere. PCEB - Parrots can eat burgers Population - consist of all members of a particular species that live within an ecosystem - populations do not exists in isolation… they form a part of a larger… Community - defined as a group of interacting populations… communities exist within… Ecosystems - include all the living and nonliving components of a defined geographical area. - an ecoys. can be anything from a small pond to large ocean Biosphere - an enormous ecosystem that encompasses all of Earth’s habitable surface 2. Define ecology Ecology - greek (oikos meaning a place to live) is the study of the interrelationships of organisms with each other and with their nonliving environment. 3. What factors affect population size? - population change through birth, death, or migration - the natural increase of a population is the difference between births and deaths - net migration of a pop. = difference between immigration (into) and emigration (out of) - pop. grows when (births - deaths) and (net migration, imm.-emig) is positive. - biggest factors are birth and death 4. What is meant by “natural increase” of a population? Natural increase – difference between births and deaths; it can be negative if death rates exceed birth rates 5. What is the net migration of a population? – difference between immigration and emigration 6. What is the growth rate of a population? A (change in) popsize = (births-deaths)+(immigration – emigration) Growth rate (r) = b-d Birth rate (b) Death rate (d) F = r x N(pop size) Growth rate (r) - is a measure of the change in population size per individual unit of time; it’s also called the rate of natural increase (based solely on births and deaths)
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*look at math in book* 7. Explain a positive/negative population growth rate. Population Growth - the number of individuals added to a population in a given time period G (population growth) G= = r x N . B > d = population increase J – curve d>b = population decrease (j curve) can be impacted by the age at which they reproduce RLF – 2.1 just enough kids to replace you 8. How do you calculate the population growth (G)? Population growth = r(growth rate) x N(population size) 9. How is an exponentially growing population shown on a graph? J CURVE Expon. growth is the pattern of continuously accelerating incase in population size. 10. What is meant by biotic potential? -maximum rate at which a population could increase 11. What factors influence biotic potential? The high biotic potential evolved because it helps ensure that, in a world filled with forces of environmental resistance, some offspring survive to reproduce. Several factors influence bp these include: - the age at which the organism first reproduces - the frequency at which reproduction occurs - the average number of offspring produced each time the organisms reproduces - the length of the organisms reproductive life span - the death rate of individuals under ideal conditions - if the size of a population that is fulfilling (approaching) its biotic potential is graphed against time, a j-shape curve will then be produced.
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