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Population Dynamics. Population Dynamics. Review: What is a population?. Group of organisms of the same species that occupy the same geographic place at the same time. Populations are described by density, distribution, and growth rate.
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Population Dynamics • Review: What is a population? Group of organisms of the same species that occupy the same geographic place at the same time
Populations are described by density, distribution, and growth rate • Population Density: number of organisms per unit ________ area NASA 1994
Spatial Distribution spacing • Dispersion: the pattern of _________ of a population within an area • 3 types • Uniform: • Clumped: • Random Organisms equal distance apart Organisms gathered in a certain area Organisms appear to be spaced out at random
Growth Rate- explains how fast a given population grows • Factors affecting the size of a population • Births: • Deaths: • Immigration: • Emigration: New organisms are produced End of an organism’s life into Movement of individuals ______ a population from another population out Movement of individuals _____ of a population and into another population
When a population is declining, what two factors are likely outpacing the other two factors? Emigration and Death
Population Growth is based on available resources • When resources are abundant, a population has the opportunity to grow _________ • This is called __________ growth rapidly exponential J-shaped curve
Most populations face limited _________ and show _________ growth • Carrying Capacity is the number of individuals that the resources in the _____________ can normally support resources logistic environment S-shaped curve
Reproductive Patterns • Other factors need to be considered such as number of ________ per reproductive cycle, ______ reproduction begins, _____ span of the organism,… • Plant and animals are placed into groups based on their __________ factors births age life reproductive
Survivorship ___________ curves tell us something about how long individuals survive in a population Type I survivorship curves are for species that have a high survival rate of the young, live out most of their expected life span and die in old age. Humans are a good example of a species with a Type I survivorship curve. Type II survivorship curves are for species that have a relatively constant death rate throughout their life span. Death could be due to hunting or diseases. Examples of species exhibiting a Type II survivorship curve are coral, squirrels, honey bees and many reptiles. Type III survivorship curves are found in species that have many young, most of which die very early in their life. Plants, oysters and sea urchins are examples of species that have Type III survivorship curves