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Population dynamics – a source of diversity Zdenˇ ek Posp´ ıˇ sil Masaryk University, Faculty of science Department of Mathematics and Statistics 7 th Summer School on Computational Biology September 15, 2011

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Population dynamics – a source of diversity

Zdenek Pospısil

Masaryk University, Faculty of scienceDepartment of Mathematics and Statistics

7th Summer School on Computational Biology

September 15, 2011

Introduction

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 2 / 18

Introduction

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 3 / 18

A bit of history

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 4 / 18

Leonhard Euler: Introductio in analysin infinitorum (1748)

Geometric growth of population

A bit of history

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 4 / 18

Thomas Robert Malthus: An Essay on the Principle ofPopulation (1798)

• The increase of population is necessarily limited by the meansof subsistence,• population does invariably increase when the means ofsubsistence increase,• the superior power of population is repressed, and the actualpopulation kept equal to the means of subsistence, by misery andvice.

A bit of history

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 4 / 18

Pierre-Francois Verhulst: Recherches mathematiques sur la loied’accroissement de la population (1845)

Self-limited (logistic) growth of population

A bit of history

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 4 / 18

Alfred J. Lotka: Analytical note on certain rhythmic relations inorganic systems (1920)

A bit of history

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 4 / 18

Alfred J. Lotka: Analytical note on certain rhythmic relations inorganic systems (1920)Vito Volterra: Variazioni e fluttuazioni del numero d’individui inspecie animali conviventi. (1926)

A bit of history

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 4 / 18

Alfred J. Lotka: Elements of physical biology (1925)Vito Volterra: Lecons sur la theorie mathematique de la lutte purla vie (1931)

A bit of history

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 4 / 18

Alfred J. Lotka: Elements of physical biology (1925)Vito Volterra: Lecons sur la theorie mathematique de la lutte purla vie (1931)Georgij F. Gause: The Struggle for existence (1934)

A bit of history

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 4 / 18

Alfred J. Lotka: Elements of physical biology (1925)Vito Volterra: Lecons sur la theorie mathematique de la lutte purla vie (1931)Georgij F. Gause: The Struggle for existence (1934)Andrej N. Kolmogorov: Sula teoria di Volterra della lota perl’esistenza (1936)

A bit of history

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 4 / 18

Charles S. Elton: Animal ecology (1927)

food chain, ecological niche, pyramid of numbers

A bit of history

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 4 / 18

Charles S. Elton: Animal ecology (1927)Alexander J. Nicholson: The balance of animal population (1933)

density (in)dependent growth

A bit of history

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 4 / 18

Charles S. Elton: Animal ecology (1927)Alexander J. Nicholson: The balance of animal population (1933)

Ch. S. Elton, A. J. Nicholson: The ten-year cycle in numbers oflynx in Canada (1942)

A bit of history

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 4 / 18

Charles S. Elton: Animal ecology (1927)Alexander J. Nicholson: The balance of animal population (1933)

Ch. S. Elton, A. J. Nicholson: The ten-year cycle in numbers oflynx in Canada (1942)

Ernest T. Seton: The arctic prairies (1912)

A bit of history

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 4 / 18

Charles S. Elton: Animal ecology (1927)Alexander J. Nicholson: The balance of animal population (1933)

Ch. S. Elton, A. J. Nicholson: The ten-year cycle in numbers oflynx in Canada (1942)

Crawford S. Holling: The functional response of predator to preydensity and its role in mimicry and population regulation (1965)

A bit of history

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 4 / 18

Patrick H. Leslie: On the use of matrices in certain populationmathematics (1945)

structured population

A bit of history

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 4 / 18

John G. Skellam: Random Dispersal in Theoretical Populations(1951)

dispersal of population in space, random walk, biological invasion

Sources, textbooks

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 5 / 18

Svire�ev, �. M. { Logofet, D. O. Usto�iqivost~biologiqeskiq soobwestv. Moskva: Nauka, 1978.

Sources, textbooks

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 5 / 18

■ Pielou E. C.: An Introduction to Mathematical Ecology.J.Willey&Sons, New York, NY, 1969

Svire�ev, �. M. { Logofet, D. O. Usto�iqivost~biologiqeskiq soobwestv. Moskva: Nauka, 1978.

Sources, textbooks

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 5 / 18

■ Pielou E. C.: An Introduction to Mathematical Ecology.J.Willey&Sons, New York, NY, 1969

■ Svire�ev, �. M. { Logofet, D. O. Usto�iqivost~biologiqeskiq soobwestv. Moskva: Nauka, 1978.

Sources, textbooks

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 5 / 18

■ Pielou E. C.: An Introduction to Mathematical Ecology.J.Willey&Sons, New York, NY, 1969

■ Svire�ev, �. M. { Logofet, D. O. Usto�iqivost~biologiqeskiq soobwestv. Moskva: Nauka, 1978.■ Kot M.: Elements of Mathematical Ecology. Cambridge

University Press: Cambridge, New York, Melbourne,Madrid, Cape Town, Singapore, Sao Paulo, 2001

Sources, textbooks

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 5 / 18

■ Pielou E. C.: An Introduction to Mathematical Ecology.J.Willey&Sons, New York, NY, 1969

■ Svire�ev, �. M. { Logofet, D. O. Usto�iqivost~biologiqeskiq soobwestv. Moskva: Nauka, 1978.■ Kot M.: Elements of Mathematical Ecology. Cambridge

University Press: Cambridge, New York, Melbourne,Madrid, Cape Town, Singapore, Sao Paulo, 2001

■ Thieme H. R.: Mathematics in Population Biology.Princeton University Press: Princeton and Oxford, 2003

Sources, textbooks

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 5 / 18

■ Pielou E. C.: An Introduction to Mathematical Ecology.J.Willey&Sons, New York, NY, 1969

■ Svire�ev, �. M. { Logofet, D. O. Usto�iqivost~biologiqeskiq soobwestv. Moskva: Nauka, 1978.■ Kot M.: Elements of Mathematical Ecology. Cambridge

University Press: Cambridge, New York, Melbourne,Madrid, Cape Town, Singapore, Sao Paulo, 2001

■ Thieme H. R.: Mathematics in Population Biology.Princeton University Press: Princeton and Oxford, 2003

■ Turchin P.: Complex Population Dynamics: atheoretical/empirical synthesis. Princeton University Press:Princeton, NJ, 2003

Sources, textbooks

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 5 / 18

■ Pielou E. C.: An Introduction to Mathematical Ecology.J.Willey&Sons, New York, NY, 1969

■ Svire�ev, �. M. { Logofet, D. O. Usto�iqivost~biologiqeskiq soobwestv. Moskva: Nauka, 1978.■ Kot M.: Elements of Mathematical Ecology. Cambridge

University Press: Cambridge, New York, Melbourne,Madrid, Cape Town, Singapore, Sao Paulo, 2001

■ Thieme H. R.: Mathematics in Population Biology.Princeton University Press: Princeton and Oxford, 2003

■ Turchin P.: Complex Population Dynamics: atheoretical/empirical synthesis. Princeton University Press:Princeton, NJ, 2003

■ Tkadlec E.: Populacnı ekologie. Struktura, rust a dynamikapopulacı. Univerzita Palackeho v Olomouci, Olomouc 2008

Sources, textbooks

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 5 / 18

■ Edelstein-Keshet L.: Mathematical Models in Biology.Random House: New York, NY, 1988

Sources, textbooks

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 5 / 18

■ Edelstein-Keshet L.: Mathematical Models in Biology.Random House: New York, NY, 1988

■ Murray J. D.: Mathematical Biology I: An Introduction.Springer-Verlag: Berlin, Heidelberg, 2001

Sources, textbooks

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 5 / 18

■ Edelstein-Keshet L.: Mathematical Models in Biology.Random House: New York, NY, 1988

■ Murray J. D.: Mathematical Biology I: An Introduction.Springer-Verlag: Berlin, Heidelberg, 2001

■ Britton N. F.: Essential Mathematical Biology.Springer-Verlag: London, 2003

Sources, textbooks

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 5 / 18

■ Edelstein-Keshet L.: Mathematical Models in Biology.Random House: New York, NY, 1988

■ Murray J. D.: Mathematical Biology I: An Introduction.Springer-Verlag: Berlin, Heidelberg, 2001

■ Britton N. F.: Essential Mathematical Biology.Springer-Verlag: London, 2003

■ de Vries G., Hillen T., Lewis M., Muller J., Schonfisch B.:A course in Mathematical Biology. Siam: Philadelphia,2006

Software

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 6 / 18

Software

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 6 / 18

Software

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 6 / 18

Software

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 6 / 18

Kreith K., Chakerian, D.: Iterative Algebra and DynamicModeling: a curriculum for the third millennium.Springer-Verlag: New York, 1999

Software

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 6 / 18

Software

Introduction

A bit of history

Sources, textbooks

Software

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

Population dynamics – 6 / 18

Henry M., Stevens H.: A Primer of Ecology with R. Springer:Dordrecht, Heidelberg, London, New York, 2009

General theory of population dynamics

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 7 / 18

Principles of population

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 8 / 18

Principles of population

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 8 / 18

1. A size of population sustains in the exponential increase ordecrease until environmental conditions cause a change ofthe status.

Principles of population

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 8 / 18

1. A size of population sustains in the exponential increase ordecrease until environmental conditions cause a change ofthe status.

2. The relative change of a population size equals to theimpact of environmental conditions.

1st principle

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 9 / 18

A size of population sustains in the exponential increase ordecrease until environmental conditions cause a change of thestatus.

x(t) = x0qt

1st principle

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 9 / 18

A size of population sustains in the exponential increase ordecrease until environmental conditions cause a change of thestatus.

x(t) = x0qt

x(t+ 1) = x0qt+1,

1st principle

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 9 / 18

A size of population sustains in the exponential increase ordecrease until environmental conditions cause a change of thestatus.

x(t) = x0qt

x(t+ 1) = qx(t),

1st principle

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 9 / 18

A size of population sustains in the exponential increase ordecrease until environmental conditions cause a change of thestatus.

x(t) = x0qt

x(t+ 1) = qx(t),x(t+ 1)− x(t)

x(t)= q − 1

1st principle

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 9 / 18

A size of population sustains in the exponential increase ordecrease until environmental conditions cause a change of thestatus.

x(t) = x0qt

x(t+ 1) = qx(t),x(t+ 1)− x(t)

x(t)= q − 1

x′(t) = x0qt ln q,

1st principle

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 9 / 18

A size of population sustains in the exponential increase ordecrease until environmental conditions cause a change of thestatus.

x(t) = x0qt

x(t+ 1) = qx(t),x(t+ 1)− x(t)

x(t)= q − 1

x′(t) = (ln q)x(t),

1st principle

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 9 / 18

A size of population sustains in the exponential increase ordecrease until environmental conditions cause a change of thestatus.

x(t) = x0qt

x(t+ 1) = qx(t),x(t+ 1)− x(t)

x(t)= q − 1

x′(t) = (ln q)x(t),x′(t)

x(t)= ln q

1st principle

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 9 / 18

q1

-1

q − 1

ln q

A size of population sustains in the exponential increase ordecrease until environmental conditions cause a change of thestatus.

x(t) = x0qt

x(t+ 1) = qx(t),x(t+ 1)− x(t)

x(t)= q − 1

x′(t) = (ln q)x(t),x′(t)

x(t)= ln q

1st principle

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 9 / 18

q1

-1

q − 1

ln q

A size of population sustains in the exponential increase ordecrease until environmental conditions cause a change of thestatus.

x(t) = x0qt

x(t+ 1) = qx(t),x(t+ 1)− x(t)

x(t)= r

x′(t) = (ln q)x(t),x′(t)

x(t)= r

2nd principle

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 10 / 18

The relative change of a population size equals to the impact ofenvironmental conditions.

2nd principle

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 10 / 18

The relative change of a population size equals to the impact ofenvironmental conditions.

x′(t)

x(t)= r

2nd principle

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 10 / 18

The relative change of a population size equals to the impact ofenvironmental conditions.

x′i(t)

xi(t)= i

(

x1(t), x2(t), . . . , xn(t))

, i = 1, 2, . . . , n

2nd principle

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 10 / 18

The relative change of a population size equals to the impact ofenvironmental conditions.

x′i(t)

xi(t)= i

(

x1(t), x2(t), . . . , xn(t))

, i = 1, 2, . . . , n

x(t+ 1)− x(t)

x(t)= r

2nd principle

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 10 / 18

The relative change of a population size equals to the impact ofenvironmental conditions.

x′i(t)

xi(t)= i

(

x1(t), x2(t), . . . , xn(t))

, i = 1, 2, . . . , n

xi(t+ 1)− xi(t)

xi(t)= i

(

x1(t), x2(t), . . . , xn(t))

,

i = 1, 2, . . . , n

2nd principle

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 10 / 18

The relative change of a population size equals to the impact ofenvironmental conditions.

x′i(t)

xi(t)= i

(

x1(t), x2(t), . . . , xn(t))

, i = 1, 2, . . . , n

xi(t+ 1)− xi(t)

xi(t)= i

(

x1(t), x2(t), . . . , xn(t))

,

i = 1, 2, . . . , n

x(t+ 1) = qx(t)

2nd principle

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 10 / 18

The relative change of a population size equals to the impact ofenvironmental conditions.

x′i(t)

xi(t)= i

(

x1(t), x2(t), . . . , xn(t))

, i = 1, 2, . . . , n

xi(t+ 1)− xi(t)

xi(t)= i

(

x1(t), x2(t), . . . , xn(t))

,

i = 1, 2, . . . , n

x(t+ 1) = erx(t)

2nd principle

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 10 / 18

The relative change of a population size equals to the impact ofenvironmental conditions.

x′i(t)

xi(t)= i

(

x1(t), x2(t), . . . , xn(t))

, i = 1, 2, . . . , n

xi(t+ 1)− xi(t)

xi(t)= i

(

x1(t), x2(t), . . . , xn(t))

,

i = 1, 2, . . . , n

xi(t+ 1) = ei(

x1(t),x2(t),...,xn(t))

x(t), i = 1, 2, . . . , n

“Fundamental equations”

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 11 / 18

Populations with overlapping generations

x′i = xii(x1, x2, . . . , xn), i = 1, 2, . . . , n

Populations with non-overlapping generations

xi(t+ 1) = ei(

x1(t),x2(t),...,xn(t))

xi(t), i = 1, 2, . . . , n

“Fundamental equations”

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 11 / 18

Populations with overlapping generations

x′i = xii(x1, x2, . . . , xn), i = 1, 2, . . . , n

Populations with non-overlapping generations

xi(t+ 1) = ei(

x1(t),x2(t),...,xn(t))

xi(t), i = 1, 2, . . . , n

i linear functions – Lotka-Volterra systemsi general functions – Kolmogorov systems

“Fundamental equations”

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 11 / 18

Populations with overlapping generations

x′i = xi(

ri − fi(x1, x2, . . . , xn))

, i = 1, 2, . . . , n

Populations with non-overlapping generations

xi(t+ 1) = eri−fi

(

x1(t),x2(t),...,xn(t))

xi(t), i = 1, 2, . . . , n

fi linear functions – Lotka-Volterra systemsfi general functions – Kolmogorov systems

f(0, 0, . . . , 0) = 0

“Fundamental equations”

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 11 / 18

Populations with overlapping generations

x′i = xi(

ri − fi(x1, x2, . . . , xn))

, i = 1, 2, . . . , n

Populations with non-overlapping generations

xi(t+ 1) = eri−fi

(

x1(t),x2(t),...,xn(t))

xi(t), i = 1, 2, . . . , n

Lotka-Volterra systems

fi(x1, x2, . . . , xn) =n∑

j=1

aijxj = Ax

“Fundamental equations”

Introduction

General theory ofpopulation dynamicsPrinciples ofpopulation

1st principle

2nd principle“Fundamentalequations”

Models with discretetime

Models withcontinuous time

Population dynamics – 11 / 18

Populations with overlapping generations

x′i = xi(

ri − fi(x1, x2, . . . , xn))

, i = 1, 2, . . . , n

Populations with non-overlapping generations

xi(t+ 1) = eri−fi

(

x1(t),x2(t),...,xn(t))

xi(t), i = 1, 2, . . . , n

Lotka-Volterra systems

fi(x1, x2, . . . , xn) =n∑

j=1

aijxj = Ax

A = (aij) – community matrix

Models with discrete time

Introduction

General theory ofpopulation dynamics

Models with discretetime

One populationTwo populations –Lotka-Volterrasystem

Models withcontinuous time

Population dynamics – 12 / 18

One population

Introduction

General theory ofpopulation dynamics

Models with discretetime

One populationTwo populations –Lotka-Volterrasystem

Models withcontinuous time

Population dynamics – 13 / 18

x(t+ 1) = erx(t), x(0) = x0 ⇒ x(t) = x0ert

One population

Introduction

General theory ofpopulation dynamics

Models with discretetime

One populationTwo populations –Lotka-Volterrasystem

Models withcontinuous time

Population dynamics – 13 / 18

x(t+ 1) = erx(t), x(0) = x0 ⇒ x(t) = x0ert

x(t+ 1) = ep(

x(t))

x(t), x(0) = x0

p decreasing – intra-specific competitionp increasing – Allee effect

One population

Introduction

General theory ofpopulation dynamics

Models with discretetime

One populationTwo populations –Lotka-Volterrasystem

Models withcontinuous time

Population dynamics – 13 / 18

x(t+ 1) = erx(t), x(0) = x0 ⇒ x(t) = x0ert

x(t+ 1) = ep(

x(t))

x(t), x(0) = x0

p decreasing – intra-specific competitionp increasing – Allee effect

p(x) = r(

1−x

K

)

– logistic equation

x > K ⇒ ep(x) > 1, x < K ⇒ ep(x) < 1

K – carrying cappacity

One population

Introduction

General theory ofpopulation dynamics

Models with discretetime

One populationTwo populations –Lotka-Volterrasystem

Models withcontinuous time

Population dynamics – 13 / 18

x(t+ 1) = erx(t), x(0) = x0 ⇒ x(t) = x0ert

x(t+ 1) = ep(

x(t))

x(t), x(0) = x0

p decreasing – intra-specific competitionp increasing – Allee effect

p(x) = r(

1−x

K

)

– logistic equation

x > K ⇒ ep(x) > 1, x < K ⇒ ep(x) < 1

K – carrying cappacity

ep(x) =q

(1 + (q − 1)x/K)b– basic equation

Two populations – Lotka-Volterra system

Introduction

General theory ofpopulation dynamics

Models with discretetime

One populationTwo populations –Lotka-Volterrasystem

Models withcontinuous time

Population dynamics – 14 / 18

x(t+ 1) = x(t)er1−a11x(t)−a12y(t)

y(t+ 1) = y(t)er2−a21x(t)−a22y(t)

Two populations – Lotka-Volterra system

Introduction

General theory ofpopulation dynamics

Models with discretetime

One populationTwo populations –Lotka-Volterrasystem

Models withcontinuous time

Population dynamics – 14 / 18

x(t+ 1) = x(t)er1−a11x(t)−a12y(t)

y(t+ 1) = y(t)er2−a21x(t)−a22y(t)

aii > 0 – intra-specific competitionaii < 0 – Allee effectaij > 0 – inter-specific competitionaij < 0 – mutualism

aijaji < 0 – predation

Models with continuous time

Introduction

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

One populationTwo populations –Lotka-VolterrasystemGause-typepredator-prey system

Population dynamics – 15 / 18

One population

Introduction

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

One populationTwo populations –Lotka-VolterrasystemGause-typepredator-prey system

Population dynamics – 16 / 18

x′ = rx, x(0) = x0 ⇒ x(t) = x0ert

One population

Introduction

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

One populationTwo populations –Lotka-VolterrasystemGause-typepredator-prey system

Population dynamics – 16 / 18

x′ = rx, x(0) = x0 ⇒ x(t) = x0ert

x′ = xp(x), x(0) = x0

p decreasing – intra-specific competitionp increasing – Allee effect

One population

Introduction

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

One populationTwo populations –Lotka-VolterrasystemGause-typepredator-prey system

Population dynamics – 16 / 18

x′ = rx, x(0) = x0 ⇒ x(t) = x0ert

x′ = xp(x), x(0) = x0

p decreasing – intra-specific competitionp increasing – Allee effect

p(x) = r(

1−x

K

)

– logistic equation

One population

Introduction

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

One populationTwo populations –Lotka-VolterrasystemGause-typepredator-prey system

Population dynamics – 16 / 18

x′ = rx, x(0) = x0 ⇒ x(t) = x0ert

x′ = xp(x), x(0) = x0

p decreasing – intra-specific competitionp increasing – Allee effect

p(x) = r(

1−x

K

)

– logistic equation

p(x) = rxa−1

(

1−( x

K

)b)

– generalized logistic equation

Two populations – Lotka-Volterra system

Introduction

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

One populationTwo populations –Lotka-VolterrasystemGause-typepredator-prey system

Population dynamics – 17 / 18

x′ = x(r1 − a11x− a12y)

y′ = y(r2 − a21x− a22y)

Two populations – Lotka-Volterra system

Introduction

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

One populationTwo populations –Lotka-VolterrasystemGause-typepredator-prey system

Population dynamics – 17 / 18

x′ = x(r1 − a11x− a12y)

y′ = y(r2 − a21x− a22y)

aii > 0 – intra-specific competitionaii < 0 – Allee effectaij > 0 – inter-specific competitionaij < 0 – mutualism

aijaji < 0 – predation

Gause-type predator-prey system

Introduction

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

One populationTwo populations –Lotka-VolterrasystemGause-typepredator-prey system

Population dynamics – 18 / 18

Gause-type predator-prey system

Introduction

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

One populationTwo populations –Lotka-VolterrasystemGause-typepredator-prey system

Population dynamics – 18 / 18

x′ = xp(x),

y′ = −dy

x – size of prey populationy – size of predator population

p(x) – prey growth rated – predator death rate

Gause-type predator-prey system

Introduction

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

One populationTwo populations –Lotka-VolterrasystemGause-typepredator-prey system

Population dynamics – 18 / 18

Holling I

Holling IIIHolling IIϕ ϕ

ϕϕ

1 1

11

2a b b + 2a

xx

x x

x′ = xp(x)− Sϕ(x)y,

y′ = −dy

x – size of prey populationy – size of predator population

p(x) – prey growth rated – predator death rate

ϕ(x) – trophic function; increasing, ϕ(0) = 0, limx→∞

ϕ(x) = 1

S – predator level of satiety

Gause-type predator-prey system

Introduction

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

One populationTwo populations –Lotka-VolterrasystemGause-typepredator-prey system

Population dynamics – 18 / 18

x′ = xp(x)− Sϕ(x)y,

y′ = −dy + κSϕ(x)y

x – size of prey populationy – size of predator population

p(x) – prey growth rated – predator death rate

ϕ(x) – trophic function; increasing, ϕ(0) = 0, limx→∞

ϕ(x) = 1

S – predator level of satietyκ – efficiency of conversion: prey into predator growth rate

Gause-type predator-prey system

Introduction

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

One populationTwo populations –Lotka-VolterrasystemGause-typepredator-prey system

Population dynamics – 18 / 18

x′ = x

(

p(x)− Sϕ(x)

xy

)

,

y′ = y(

− d+ κSϕ(x))

Gause-type predator-prey system

Introduction

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

One populationTwo populations –Lotka-VolterrasystemGause-typepredator-prey system

Population dynamics – 18 / 18

x′ = x

(

p(x)− Sϕ(x)

xy

)

,

y′ = y(

− d+ κSϕ(x))

ϕ(x) =

{

x/(2a), x < 2a

1, x ≥ 2a

Gause-type predator-prey system

Introduction

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

One populationTwo populations –Lotka-VolterrasystemGause-typepredator-prey system

Population dynamics – 18 / 18

x′ = x

(

p(x)− Sϕ(x)

xy

)

,

y′ = y(

− d+ κSϕ(x))

ϕ(x) =

{

x/(2a), x < 2a

1, x ≥ 2a

ϕ(x) =xk

xk + ak

ϕ(x) = 1− 2−(x/a)k

Gause-type predator-prey system

Introduction

General theory ofpopulation dynamics

Models with discretetime

Models withcontinuous time

One populationTwo populations –Lotka-VolterrasystemGause-typepredator-prey system

Population dynamics – 18 / 18

x′ = x

(

p(x)− Sϕ(x)

xy

)

,

y′ = y(

− d+ κSϕ(x))

ϕ(x) =

{

x/(2a), x < 2a

1, x ≥ 2a– Holling I

ϕ(x) =xk

xk + ak– Michaelis-Menten

ϕ(x) = 1− 2−(x/a)k – Ivlev

a – level of “half saturation”