Chapter 53: Population Ecology. Essential Knowledge 2.a.1 – All living systems require constant...

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Chapter 53: Population Ecology

Transcript of Chapter 53: Population Ecology. Essential Knowledge 2.a.1 – All living systems require constant...

Page 1: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Chapter 53: Population Ecology

Page 2: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Essential Knowledge 2.a.1 – All living systems require constant

input of free energy (53.3 & 53.4). 2.d.1 – All biological systems from cells and

organisms to populations, communities, and ecosystems are affected by complex biotic and abiotic interactions involving exchange of matter and free energy (53.1 – 53.5).

4.a.5 – Communities are composed of populations of organisms that interact in complex ways (53.1-53.3, 53.5 & 53.6).

Page 3: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Population Ecology Study of the factors that affect population

size and composition. Population:

Def: Individuals of a single species that occupy the same geographic area

Ex: Humans living in Indianapolis, IN

Page 4: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Important Characteristics1. Density2. Dispersion

Page 5: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Density Number of individuals per unit area or

volume. Ex:

Diatoms - 5 million/m3

Trees - 5,000/km2

Deer - 4/km2

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Dispersion Pattern of spacing among individuals. Types:

1. Clumped2. Uniform/Even3. Random

Page 7: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.
Page 8: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Clumped Dispersion May result form a patchy environment. May increase chances for survival. Ex:

Schooling behaviorFlocks of birds

Page 9: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Uniform Dispersion

Often the result of antagonistic interactions between individuals.

Known as even or regular dispersion

Ex: TerritoriesSpacing between desert plants

Page 10: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Random Dispersion Often the result of the absence of strong

attractions or repulsions between individuals.

Not a common pattern.

Page 11: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Demography The study of the vital statistics that affect

population size. Ex: Birth and Death rates Factors of Demography:

Age structure of populationBirth and death ratesGeneration timeSex ratio and reproductive behavior

Page 12: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Life Tables Mortality summary for a cohort of

individuals. First developed from life insurance studies. What do they show us?

Mortality rate per yearLife span of the organismFecundity (birth rate)

Page 13: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.
Page 14: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Survivorship Curve Plot of the numbers of a cohort still alive

over time. Curve Types:

Type IType IIType III

Page 15: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Type I Low early deaths. High late deaths. Ex:

HumansOther large

mammals

Page 16: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Type II Constant death rate. Ex:

Annual plantsMany invertebrates

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Type III High early deaths. Low late deaths. Ex:

TreesOysters

Page 18: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Comment Curve type may change between young and

adults. Ex: Nestlings - Type III

Adult Birds- Type II

Page 19: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Life History Strategies1. "r" or Opportunistic species2. "k" or Equilibrial species

Page 20: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

"r" Species

Increase fitness by producing as many offspring as possible.

Do this by:Early maturationMany reproductive eventsMany offspring

Page 21: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Result Maximize reproduction so that at least a

few offspring survive to the next generation. Most offspring die (Type III curve).

Page 22: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

"k" Species

Increase fitness by having most offspring survive.

Do this by:High parental careLate maturationFew reproduction eventsFew offspring.

Page 23: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Result Maximize survivorship of each offspring. Few offspring, but most survive (Type I

curve).

Page 24: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

What is the strategy? For a weed? For an endangered species? For Garden Pests?

Page 25: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Population Growth DN/Dt = b - d Where:

N= population sizet = timeb = birth rated = death rate

Page 26: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Rate of Increase r = difference between birth rate and death

rate. r = b - d

Page 27: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Equation with “r”: DN/Dt = rN N = population size t = time r = rate of increase

Page 28: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

From Calculus

The equation DN/Dt = rN becomes:dN/dt = rmax Nrmax = intrinsic rate of increase

Page 29: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Exponential Growth

dN/dt = rmax N Characteristic of "r" species. Produces a “J-shaped” growth curve. Only holds for ideal conditions and unlimited

resources.

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Page 31: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Logistic Growth dN/dt = rmax N K-N

K K = carrying capacity Result of logistic growth?

“S-shaped” growth curveCharacteristic of “k” speciesCommon when resources are limited

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Page 33: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Comment K is not a constant value. Populations often oscillate around “K” as

the environment changes.

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Page 35: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Additional Comments Populations often overshoot “K”, then drop

back to or below “K”. AP Exam rarely asks you to work the

equations, but you should be able to give them.

Page 36: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Regulation of Population Size

1. Density- Dependent Factors2. Density- Independent Factors

Page 37: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Density-Dependent Affect is related to N As N increases, mortality increases Ex: Food, nesting space, disease

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Page 39: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Density-Independent

Affect is not related to N Mortality not related to population size Ex: Weather and climate

Page 40: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Population Cycles Cyclic changes in N over time Often seen in predator/prey cycles Ex: Snowshoe Hare – Lynx Causes?

Density dependent factorsChemical cyclesSaturation strategy to confuse predators

Page 41: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.
Page 42: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Age Structure Diagrams Show the percent of a population in

different age categories Method to get data similar to a Life Table,

but at one point in time

Page 43: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.
Page 44: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Importance Can be used to predict future population

growth trends, especially for long lived species.

Page 45: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Exponential Growth Produces age structures that are a triangle

or pyramid shape

Logistic Growth Produces age structures that have even

sizes between most age categories

Page 46: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Declining Populations Produce age structures with a narrow base

and wider middles

Page 47: Chapter 53: Population Ecology. Essential Knowledge  2.a.1 – All living systems require constant input of free energy (53.3 & 53.4).  2.d.1 – All biological.

Summary Identify the difference between population density

and dispersion. Recognize the types of dispersion patterns and the

interactions that lead to them. Identify the types of survivorship curves. Recognize the characteristics of "r" and "k" life

history strategies. Identify the types of population growth models. Identify factors that regulate population size. Recognize how age-structure diagrams relate to

population growth.