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Exam 2

by: Lauren Sadowski
Lauren Sadowski
Dr. Amanda Dickens

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Normally, the professor posts a study guide; however, we had to make our own for this exam. This study guide is made from a combination of class notes and the book! Enjoy!
Dr. Amanda Dickens
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This 9 page Study Guide was uploaded by Lauren Sadowski on Tuesday October 13, 2015. The Study Guide belongs to BIO 366 at University of North Carolina - Wilmington taught by Dr. Amanda Dickens in Summer 2015. Since its upload, it has received 51 views. For similar materials see Ecology in Biology at University of North Carolina - Wilmington.


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Date Created: 10/13/15
Exam 2 Study Guide Chapters 1112 and 13 Chapter 11 Concepts 1 The distribution of populations is limited to ecologically suitable habitats 2 Population distributions have ve important characteristics 3 The distribution properties of populations can be estimated 4 Population abundance and density are related to geographic range and adult body size Dispersal is essential to colonizing new areas Many populations live in distinct patches of habitat mp1 Distribution of populations gt Spatial structures the pattern of density and spacing of individuals in a population gt Fundamental niche the range of abiotic conditions under which species can persist gt Realized niche the range of abiotic and biotic conditions under which a species persists gt Geographic range a measure of the total area covered by a population What biotic interactions can prevent a population from persisting an area Biotic interactions are things that are alive abiotic interactions are things such as H2002 etc Biotic interactions would be lack of food lack of space that would not allow the animals or organisms to live and reproduce gt Ecological niche modeling the process of determining the suitable habitat conditions for a species gt Ecological envelope the range of ecological conditions that are predicted to be suitable for a species Predicting the potential geographic range of a species is dif cult when only a few individuals exists researchers can use historic distributions of species Ecological niche modeling can predict the expansion of invasive species modeling invasive species Population characteristics gt Endemic species that live in a single often isolated locations gt Cosmopolitan species with very large geographic range that can span several continents gt Abundance the total number of individuals in a population that exist within a de ned area gt Density in a population the number of individuals per unit are or volume gt Population dispersal the movement of individuals from one area to another Three types of dispersals clustered evenly spaced random gt Clustered a pattern of population dispersion in which individuals are aggregated in discrete groups gt Evenly spaced dispersal a pattern of dispersion of population in which each individual maintains an uniform distance between itself and its neighbors gt Random dispersal a pattern of dispersion of a population in which the position of each individual is independent of the position of other individuals in the population What are the traits that lead to speci c dispersals Clustered think about an oasis in the desert Of course those are clustered because animals are drawn to those rare sources of nutrients Evenly spaced think about aspen trees that reproduce through their roots naturally the trees are not going to reproduce on top of each other The trees need distance in order to survive Random dispersals think about humans We can live anywhere because of resources therefore humans are found in different areas Make sure you have can give examples of these dispersals Quantifying individuals gt Census counting ever individual in a population gt Area and volume based surveys surveys that de ne the boundaries of an area or volume and then count all of the individuals in the same space gt Line transect surveys surveys that count the number of individuals observed as one moves along a line gt Mark recapture survey a method of population estimation in which researchers capture and mark a subset of a population from an area return it to the area and then capture a second sample of the population after some time has passed Population size is estimated by Initially captured individuals population size marked recaptured total individual in 2nCI sample Population abundance and range populations with high abundance also have a large geographic range Make sure you know Reasons for trends Large variations Population density v body size generally the density of a population is negatively correlated to the body size of the species Dispersal Limitations gt Dispersal limitations the absence of a population from suitable habitat because of barriers to dispersal gt What are barriers Barriers are things that prevent animals organisms from migrating reproducing and living For an example the ocean keeps organisms from crossing the oceans This is important for animals that are migrating it means they are limited to only the areas they can reach gt Do humans cause barriers or break down barriers Yes we do both By building highways animals are not able to migrate That limits the gene pools and can separate populations Humans can break barriers by damming rivers Since the rivers are no longer owing animals are able to move through the old rivers gt Habitat corridor a strip of favorable habitat located between two large patches of habitat that facilitates dispersal The ideal free distribution Individuals choose habitats that provide the most energy gtmore individuals move to the habitat gt reduced per capita bene t Why is the ideal free distribution pattern rarely seen in nature Imagine this There is a place on Earth where food is plentiful the air is fresh and not polluted there is plenty of room What happens Everyone wants to move there and live there Now there is not enough room food is going scarce and the air is polluted So now people will leave This is how it is in nature but of course there is never a place that is as perfect as that scenario That is why it is rare to see the ideal free distribution model There will never be a place that has everything Organisms will always be settling whether the organisms settle for polluted water but has great food resources has plenty of room but does not have the best food gt Subpopulation when a larger population is broken up into smaller groups that live in isolated areas gt Basic metapopulation modela model that describes a scenario in which there are patches of suitable habitat embedded within a matrix of unsuitable habitat gt sink metapopulation model a population model that builds upon the basic metapopulation model and accounts for the fact that not all patches of suitable habitat are equal quality gt Source subpopulation in high quality habitats subpopulations that serve as a source 0 dispersers within a metapopulations gt Landscape metapopulation model a population model that considers both differences in the quality of the suitable patches and the quality of the surrounding matrix N population size M number of individual marked and sampled R number of marked individuals during 2nCI sample effort C number of individual captured during 2nCI sample effort RCMN SOLVING FOR N POPULATION SIZE Chapter 12 Concepts 1 Under ideal conditions populations grow rapidly 2 Populations have growth limits 3 Population growth rate is in uenced by the proportions of individuals in different age size and life history Population demography Demography the study of populations Growth rate in a population the number of new individuals that are produced in a given amount of time minus the number of individuals that die Intrinsic growth rate r the highest possible per capita growth rate for a population Under ideal conditions individuals experience what level of growth and death rates Exponential growth rate NtN0equotrt Nt future population size No current population size r intrinsic growth rate t time over which populations grow J shaped curve The rate of a populations growth at any point in time is the derivative of this equation dndtrN The geometric growth model is expressed as a ratio of a population s size in one year to its size in the preceding year the symbol for this looks like an upside down y and for these notes I am going to type them as y According to the geometric growth model the size of a population after one time interval is N1N02 the zero is below the N After two time intervals the population size would be N2N0yyN0yquot2 More generally after t time intervals NtN0yquot2 To determine the change in population size between initial population size and t time intervals Population decrease y lt1 rlt0 Population constant y1 r0 Population increase ygt1 rgt0 Density independent limitations gt density independent factors that limit population size regardless of the populations density gt Density dependent factors that affect population size in relation to the populations density gt Negative density dependence when the rate of population growth decreases as population density increases gt Positive density dependence when the rate of population growth increases as population density increases Also known as inverse density and the Aee effect Low densities can also lead to harmful effects of inbreeding and higher predation risks Populations are regulated by both positive and negative density dependence gt Carrying capacity k the maximum population size that can be supported by the environment gt Logistic growth model a growth model that describes slowing growth of populations at high densities gt S shaped curve the shape of the curve when a population is graphed over time using the logistic growth model gt In ection point the point on a sigmoidal growth curve at which the population achieves its highest growth rate As the population increases from a very small size the rate of increase grows until reaching 5 the carrying capacity Rate of per capita increase can be model as 1NdNdt Individuals in the population continually decline in their ability to contribute to population growth Population growth Survivorship curve three types gt Type I starts off with offspring that live a long time and then die at an average age Imagine Iarge mammals and humans gt Type II starts off with offspring that die at random Imagine birds or rodents They have the same chance of dying at anytime of their lives gt Type III has many offspring that die quickly Imagine bugs and sea turtles Life tables tables that contain cIass speci c survival and fecundity data Because it is often dif cult to ascertain paternity Iife tables are typically based on the number of female offspring per female Xage cIass Nx the number of individuals in each age class immediately after the population has produced offspring Sx the survival rate from one age class to the next age class nx1nx Bx the fecundity of each age class Stable age distribution when the age structure of population does not change over time occurs when survival and fecundity of each age class stays constant over time Survivorship to the second year l2 is calculated by 2llsl Net reproductive rate R0 total number of female offspring that we expect an average female to produce over the course of her life R0gt1 populations grow R0lt1 populations decline When geometric growth rate or intrinsic growth rate is estimated from a life table it is assumed that the life table has a stable age distribution Age distributions uctuate due to environmental conditionsany approximation a of y or r is restricted to the environmental conditions that the population experiences at the time of measurement gt Cohort life table a table that follows a group of individual born at the same time from birth to the death of the last individual Why are these tables useful These tables help with protecting organisms and their populations Chapter 13 Concepts 1 Population uctuate naturally over time 2 Density dependence with time delays can cause populations to be inherently cyclic 3 Chance events can cause small populations to go extinct 4 Metapopulations are composed of subpopulations that can experience independent population dynamics across space Population uctuations All populations experience uctuations due to factors such as availability of resources predations competition disease parasites and climate Fluctuations include random and cyclic changes through time Many populations tend to remain stable over long periods of time However some populations exhibit much wider uctuations When an age group contains a high or low number of individuals the populations are likely to experience high birth or death rates in the past Populations in nature rarely follow a smooth rise to their carrying capacity gt Overshoot when a population grows beyond the carrying capacity gt Dieoff a substantial decline in density that typically goes well below the carrying capacity gt Population cycles regular oscillation of population over a longer period of time Cyclic Behavior of Populations Populations have an inherent periodicity and tend to uctuate up and down The time needed to complete a full cycle depends on the species of organisms being studied Populations are stable when hanging straight up and down Momentum causes the population to overshoot Populations are stable at the carrying capacity When reductions in size occurs the populations will grow and overshoot the carrying capacity Overshooting can occur when there is delay between the initiation of breeding and the time that offspring are added to the population Population cycles can be modeled by starting with the logistic growth model and incorporate delay between the change in environmental conditions and the time the populations takes to reproduce Delayed density dependence when density dependence occurs based on a population density at some time in the past Extinctions in small populations gt Deterministic model a model that is designed to predict a result without accounting for random variation in population growth rate gt Stochastic model a model that incorporates random variation in population growth rate gt Demographic stochasticity variation in birth rates and death rates due to random differences among individuals gt Environmental stochasticity variation in birth rates and death rates due to random changes in the environmental conditions There is an increased chance of having a string of bad years as time goes by Smaller populations are at more risk for extinction if they experience multiple bad years Patchy Habitats Habitat often occurs as patches of suitable habitat surrounded by unwanted habitat gt Habitat fragmentation the process of breaking up large habitats into a number of smaller habitats p the fraction of habitat patches that are occupied e the probability of each patch becoming unoccupied C the probability of patch becoming colonized the proportion of occupied patches when colonization and extinction have reached an equilibrium p1ec habitat patches are rarely equal in quality some patches are larger or may contain better resources smaller patches are more likely to experience higher rates of extinction because they have less resources Unoccupied patches that are close to occupied patches are more like to be colonized gt Rescue effects when dispersers supplement a declining subpopulation and thereby prevent the subpopulation from going extinct These notes and de nitions are from the book Ecology the Economy of nature by Robert Ricklefs and Rick Relyea 7th edition and from Amanda Dickens professor If you have further questions I would advise looking at those sources


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