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125 Cards in this Set
- Front
- Back
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Population ecology |
The study of population (especially population abundance) and how they change over time |
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Demography |
The study of group characteristics of a population, their changes over time and prediction of future changes |
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Two types of Density |
Crude density and specific (ecological) density |
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Crude density |
Density per unit of total space |
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Specific density |
Density per unit of heritable space Includes only that portion of total space that can actually be colonised by the population |
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Mark-recapture method |
Using this method a small random sample of the population is captured, marked and then released to disperse within the general population |
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Calculating population size based on Mark recapture method |
We assume that the ratio of marked to unmarked individuals in the second sample taken is the same as the first sample N (population size) = (total ind marked in first sample*size of second sample) / no of marked individuals recaptured in second sample |
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Natality |
Refers to the birth of individuals in a population |
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Natality rate (or birth rate) |
Expressed as the number of individuals per female per unit time |
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Maximum natality (absolute or physiological natality) |
Theoretical maximum number of individuals produced under ideal environmental conditions (i.e. no ecological limiting factors) and is a constant for a given population |
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Maximum natality (absolute or physiological natality) |
Theoretical maximum number of individuals produced under ideal environmental conditions (i.e. no ecological limiting factors) and is a constant for a given population |
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Ecological or realised natality |
Refers to the number of individuals produced under an actual or specific environmental condition |
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Maximum natality (absolute or physiological natality) |
Theoretical maximum number of individuals produced under ideal environmental conditions (i.e. no ecological limiting factors) and is a constant for a given population |
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Ecological or realised natality |
Refers to the number of individuals produced under an actual or specific environmental condition |
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Fecundity |
Described as the maximum reproductive output potential of an individual under ideal environmental conditions This limit is set by the genotype. |
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Maximum natality (absolute or physiological natality) |
Theoretical maximum number of individuals produced under ideal environmental conditions (i.e. no ecological limiting factors) and is a constant for a given population |
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Ecological or realised natality |
Refers to the number of individuals produced under an actual or specific environmental condition |
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Fecundity |
Described as the maximum reproductive output potential of an individual under ideal environmental conditions This limit is set by the genotype. |
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Fertility |
Describes the actual reproductive performance of an individual under prevailing environmental conditions and it’s a generalisation of the terms birth rate and natality rate. |
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Mortality |
Refers to the death of individuals in a population |
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Mortality |
Refers to the death of individuals in a population |
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Minimum mortality |
A constant for a population represents the loss under ideal or non limiting conditions |
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Mortality |
Refers to the death of individuals in a population |
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Minimum mortality |
A constant for a population represents the loss under ideal or non limiting conditions |
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Ecological mortality (or realised mortality) |
The loss of individuals under a given environmental condition |
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Life table |
Information of the death and survivor of a population with respect to age is represented in the form of table It is an age specific account of mortality To build a life table we need to determine the number of individuals that die in each age class and proportion of the cohort surviving from one age class to the next |
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Life table |
Information of the death and survivor of a population with respect to age is represented in the form of table It is an age specific account of mortality To build a life table we need to determine the number of individuals that die in each age class and proportion of the cohort surviving from one age class to the next |
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Survivorship curve |
Plot the number of surviving individuals to a particular age |
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Highly convex curve (type I curve) |
Characteristic of the species in which the population mortality rate is low until near the end of the lifespan It is known as the death at senescence curve Deer, mountain sheep and man |
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Life table |
Information of the death and survivor of a population with respect to age is represented in the form of table It is an age specific account of mortality To build a life table we need to determine the number of individuals that die in each age class and proportion of the cohort surviving from one age class to the next |
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Survivorship curve |
Plot the number of surviving individuals to a particular age |
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Highly convex curve (type I curve) |
Characteristic of the species in which the population mortality rate is low until near the end of the lifespan It is known as the death at senescence curve Deer, mountain sheep and man |
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Highly concave curve ( type III curve) |
Characteristic of those species where the mortality rate is high during the young stages Oysters or shellfish show this type of curve In oysters, mortality is extremely high during free-swimming larval stages, but once an individual is well established on a favourable substrate, life expectancy improves considerably |
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Life table |
Information of the death and survivor of a population with respect to age is represented in the form of table It is an age specific account of mortality To build a life table we need to determine the number of individuals that die in each age class and proportion of the cohort surviving from one age class to the next |
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Survivorship curve |
Plot the number of surviving individuals to a particular age |
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Highly convex curve (type I curve) |
Characteristic of the species in which the population mortality rate is low until near the end of the lifespan It is known as the death at senescence curve Deer, mountain sheep and man |
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Highly concave curve ( type III curve) |
Characteristic of those species where the mortality rate is high during the young stages Oysters or shellfish show this type of curve In oysters, mortality is extremely high during free-swimming larval stages, but once an individual is well established on a favourable substrate, life expectancy improves considerably |
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Type II curve |
The rate of mortality is constant at all age groups Birds and humans exposed to poor nutrition and hygiene |
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Iteroparous |
Type I survivorship curves are typical of organisms which are likely to breed several times during the course of their lifespan |
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Iteroparous |
Type I survivorship curves are typical of organisms which are likely to breed several times during the course of their lifespan |
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Semelparous |
Type III curve Breed only once during their lifetime |
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Dispersion |
The spatial or temporal distribution pattern of individuals of a population Regular, Random or Clumped (aggregated or contagious) |
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Dispersion |
The spatial or temporal distribution pattern of individuals of a population Regular, Random or Clumped (aggregated or contagious) |
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Regular dispersion (uniform or even distribution) |
The individuals are more or less spaced at an equal distance from one another Individuals are more evenly spaced than expected by chance This is rare in nature but is common in managed systems like croplands A regular distribution pattern may be the result of competition or social interaction |
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Random dispersion |
The position of one individual is unrelated to the positions of another individual Relatively rare in nature |
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Dispersion |
The spatial or temporal distribution pattern of individuals of a population Regular, Random or Clumped (aggregated or contagious) |
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Regular dispersion (uniform or even distribution) |
The individuals are more or less spaced at an equal distance from one another Individuals are more evenly spaced than expected by chance This is rare in nature but is common in managed systems like croplands A regular distribution pattern may be the result of competition or social interaction |
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Random dispersion |
The position of one individual is unrelated to the positions of another individual Relatively rare in nature |
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Clumped dispersion (contagious or aggregated dispersion) |
Individuals aggregated into groups of varying sizes Most populations |
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Dispersion |
The spatial or temporal distribution pattern of individuals of a population Regular, Random or Clumped (aggregated or contagious) |
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Regular dispersion (uniform or even distribution) |
The individuals are more or less spaced at an equal distance from one another Individuals are more evenly spaced than expected by chance This is rare in nature but is common in managed systems like croplands A regular distribution pattern may be the result of competition or social interaction |
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Random dispersion |
The position of one individual is unrelated to the positions of another individual Relatively rare in nature |
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Clumped dispersion (contagious or aggregated dispersion) |
Individuals aggregated into groups of varying sizes Most populations |
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Age structure |
The proportion of individuals in each age group Pre- reproductive, reproductive, post-reproductive |
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Dispersion |
The spatial or temporal distribution pattern of individuals of a population Regular, Random or Clumped (aggregated or contagious) |
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Regular dispersion (uniform or even distribution) |
The individuals are more or less spaced at an equal distance from one another Individuals are more evenly spaced than expected by chance This is rare in nature but is common in managed systems like croplands A regular distribution pattern may be the result of competition or social interaction |
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Random dispersion |
The position of one individual is unrelated to the positions of another individual Relatively rare in nature |
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Clumped dispersion (contagious or aggregated dispersion) |
Individuals aggregated into groups of varying sizes Most populations |
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Age structure |
The proportion of individuals in each age group Pre- reproductive, reproductive, post-reproductive |
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Expanding population |
Rapidly growing population with a high birth rate Individuals of the pre reproductive age class is greater than reproductive age class A pyramid shaped age structure |
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Dispersion |
The spatial or temporal distribution pattern of individuals of a population Regular, Random or Clumped (aggregated or contagious) |
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Regular dispersion (uniform or even distribution) |
The individuals are more or less spaced at an equal distance from one another Individuals are more evenly spaced than expected by chance This is rare in nature but is common in managed systems like croplands A regular distribution pattern may be the result of competition or social interaction |
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Random dispersion |
The position of one individual is unrelated to the positions of another individual Relatively rare in nature |
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Clumped dispersion (contagious or aggregated dispersion) |
Individuals aggregated into groups of varying sizes Most populations |
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Age structure |
The proportion of individuals in each age group Pre- reproductive, reproductive, post-reproductive |
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Expanding population |
Rapidly growing population with a high birth rate Individuals of the pre reproductive age class is greater than reproductive age class A pyramid shaped age structure |
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Stable population |
The number of individuals in the pre-reproductive age group and the reproductive age group are more or less equal in size Post- reproductive groups remains the smallest Bell shaped curve |
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Dispersion |
The spatial or temporal distribution pattern of individuals of a population Regular, Random or Clumped (aggregated or contagious) |
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Regular dispersion (uniform or even distribution) |
The individuals are more or less spaced at an equal distance from one another Individuals are more evenly spaced than expected by chance This is rare in nature but is common in managed systems like croplands A regular distribution pattern may be the result of competition or social interaction |
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Random dispersion |
The position of one individual is unrelated to the positions of another individual Relatively rare in nature |
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Clumped dispersion (contagious or aggregated dispersion) |
Individuals aggregated into groups of varying sizes Most populations |
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Age structure |
The proportion of individuals in each age group Pre- reproductive, reproductive, post-reproductive |
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Expanding population |
Rapidly growing population with a high birth rate Individuals of the pre reproductive age class is greater than reproductive age class A pyramid shaped age structure |
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Stable population |
The number of individuals in the pre-reproductive age group and the reproductive age group are more or less equal in size Post- reproductive groups remains the smallest Bell shaped curve |
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Diminishing population |
Low proportion of pre-reproductive age class individuals due to reduced birth rate Urn shaped structure |
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Closed population |
Change in population is only related to birth and death of individuals |
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Open population |
Birth , death, immigration, emigration result in change in population |
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Exponential growth |
There is no limitation on growth I.e. in an idealised unlimited environment |
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Exponential growth |
There is no limitation on growth Idealised environment |
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Intrinsic rate of increase |
During exponential population growth under an ideal unlimited environment, per capita rate of increase is maximum |
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Intrinsic rate of increase |
During exponential population growth under an ideal unlimited environment, per capita rate of increase is maximum |
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Biotic potential (or reproductive potential) |
The maximum value of r It is the maximum per capita growth rate in the absence of environmental resistance |
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Intrinsic rate of increase |
During exponential population growth under an ideal unlimited environment, per capita rate of increase is maximum |
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Biotic potential (or reproductive potential) |
The maximum value of r It is the maximum per capita growth rate in the absence of environmental resistance |
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When resources are unlimited |
When resources (food and space) in a habitat are unlimited, all members of a species have the ability to grow exponentially The population size that increases exponentially at a constant rate results in a J-shaped growth curve when population size (N) is plotted over time (t) |
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Carrying capacity |
The number of individuals of a particular species that a particular environment can support indefinitely Carrying capacity is not fixed but varies over space and time with the abundance of limiting resources |
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Carrying capacity |
The number of individuals of a particular species that a particular environment can support indefinitely Carrying capacity is not fixed but varies over space and time with the abundance of limiting resources |
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Verhulst- Pearl logistic growth |
The growth of a population eventually slows as the population reaches the carrying capacity for environment |
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Logistic model of population growth |
Produces a sigmoid (S-shaped) growth curve when population size is plotted over time |
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Two kinds of life tables |
Cohort and static |
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Two kinds of life tables |
Cohort and static |
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Cohort (dynamic or horizontal) |
The fate of a group of same aged individuals is followed from birth to their death |
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Two kinds of life tables |
Cohort and static |
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Cohort (dynamic or horizontal) |
The fate of a group of same aged individuals is followed from birth to their death |
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Static life table |
Made from data collected from all ages at one particular time Assumption that each age class is samples in proportion to its numbers in the population and the death and birth rates are constant and the population is stable |
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Two kinds of life tables |
Cohort and static |
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Cohort (dynamic or horizontal) |
The fate of a group of same aged individuals is followed from birth to their death |
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Static life table |
Made from data collected from all ages at one particular time Assumption that each age class is samples in proportion to its numbers in the population and the death and birth rates are constant and the population is stable |
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Gross reproductive rate |
The sum of mx value across all the ages provides an estimate of the average number of female offspring born to a female over her lifetime |
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Two kinds of life tables |
Cohort and static |
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Cohort (dynamic or horizontal) |
The fate of a group of same aged individuals is followed from birth to their death |
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Static life table |
Made from data collected from all ages at one particular time Assumption that each age class is samples in proportion to its numbers in the population and the death and birth rates are constant and the population is stable |
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Gross reproductive rate |
The sum of mx (age specific fertility) value across all the ages provides an estimate of the average number of female offspring born to a female over her lifetime |
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Net reproductive age |
Age specific fertility (mx) * age specific survival (lx) |
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Density dependent population factors |
Affect population growth as the function of population density Can have either a positive or a negative correlation to population size As population size increases either birth rate declines or mortality rate increases or both. It is a negative feedback |
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Allee affect |
Growth rate increases with population size. Positive feedback. Reasons : Mate limitation reduced Decrease vulnerability to predators No inbreeding depression |
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Allee affect |
Growth rate increases with population size. Positive feedback. Reasons : Mate limitation reduced Decrease vulnerability to predators No inbreeding depression |
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Density independent factors |
Effect population to on growth irrespective of density of the population Natural catastrophes such as hurricanes, floods, and seasonal variation in weather patterns |
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Life history traits |
Traits that describe life history of an organism Include age at first reproduction event, number and size of offspring, reproductive lifespan and length of life |
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Life history theory |
Explains how natural selection and other evolutionary forces shape organisms to optimise their survival and reproduction in the face of ecological challenges posed by the environment |
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Life history theory |
Explains how natural selection and other evolutionary forces shape organisms to optimise their survival and reproduction in the face of ecological challenges posed by the environment |
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Trade offs |
Caused by competitive allocation of limited resources to one life history trait versus the other within a single individual A trade off exists when an increase in one life history trait (improving fitness) is coupled with a decrease in another life history trait (reducing fitness) |
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Life history theory |
Explains how natural selection and other evolutionary forces shape organisms to optimise their survival and reproduction in the face of ecological challenges posed by the environment |
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Trade offs |
Caused by competitive allocation of limited resources to one life history trait versus the other within a single individual A trade off exists when an increase in one life history trait (improving fitness) is coupled with a decrease in another life history trait (reducing fitness) |
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Individuals reproductive effort |
Together the total energetic costs of reproduction per unit time |
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R |
Intrinsic rate of increase |
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R |
Intrinsic rate of increase |
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K |
Carrying capacity |
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R |
Intrinsic rate of increase |
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K |
Carrying capacity |
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High r |
Strongly variable and unpredictable environment |
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R |
Intrinsic rate of increase |
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K |
Carrying capacity |
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High r |
Strongly variable and unpredictable environment |
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High K |
Long lived fairly constant or predictable environmental conditions |
