Chapter 3: Populations (copy) Recreated

Survivorship curves

It show age-distribution characteristics of species, reproductive strategies, and life history

Biotic potential

The maximum reproductive capacity of an organism under optimum environmental conditions

Environmental Resistance

Any factor that inhibits an increase in the number of organisms in the population

J-Curve

It represents a population growth occurs in a new environment when the population density of an organism increases rapidly in an exponential or logarithmic form, but then stops abruptly as environmental resistance or another factor suddenly impacts the population growth

S-Curve

It occurs when, in a new environment, the population density of an organism initially increases slowly but then stabilizes due to the finite amount of resources available

Limiting Factor

It can be any resource or environmental condition that limits the abundance, distribution, and/or growth of a population

Density-dependent limiting factors

These are factors whose effects on the size or growth of the population vary with the density of the population

Density-independent factors

These are factors that limit the size of a population, and their effects are not dependent on the number of individuals in the population

Rule of 70

It helps to explain the time periods involved in exponential population growth occurring at a constant rate

Doubling time

It is the amount of time it takes for a population to double in size

Age-structure diagrams

These are determined by birth rate, generation time, death rate, and sex ratios

Pyramid-shaped age-structure diagram

It indicates that the population has high birth rates and the majority of the population is in the reproductive age group

Bell shape age-structure diagram

It indicates that pre-reproductive and reproductive age groups are more nearly equal, with the post-reproductive group being smallest due to mortality

Urn-Shaped age-structure diagram

It indicates that the post-reproductive group is largest and the pre-reproductive group is smallest, a result of the birth rates falling below the death rate, and is characteristic of declining populations

Total fertility rate (TFR)

The average number of children that each woman will have during her lifetime

Demographic transition

It is the transition from high birth and death rates to lower birth and death rates as a country or region develops from a pre-industrial to an industrialized economic system

Stage 1

Pre-Industrial (High Stationary) (Low growth)

Stage 2

Transitional (Early Expanding) (Very High growth Rate)

Stage 3

Industrial (Late Expanding) (Slow growth)

Stage 4

Post-Industrial (Low Stationary) (No or negative growth)

Birth Rate Formula

Birth Rate (%) = \[(total births/total population)\] × 100

Crude Birth Rate Formula

CBR = \[(*b* ÷ *p*) × 1,000\]

Death Rate Formula

Death Rate (%) = \[(total deaths/total population)\]× 100

Crude Death Rate Formula

CDR = \[(*d* ÷ *p*) × 1,000\]

Doubling Time Formula

Doubling Time = 70/% growth rate

Percent Rate of Change Formula

Percent Rate of Change = \[(new # - old #)/old #\] × 100

Population Growth Rate Formula

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Based on _________, even if all other factors are favorable, the one that is least favorable will dictate the growth, abundance, or distribution of the population of a species.

Liebig’s law of the minimum

This type of population growth is termed “_________” since the growth rate depends on the number of organisms in the population.

density-dependent

This type of population growth rate is known as “_______,” a regulation of the growth rate is not tied to the population density until the resources are exhausted and the population growth crashes.

density-dependent

Type I Survivorship

Exhibit high survivorship through life

Type II Survivorship

Constant proportion of loss over time

Type III Survivorship

very high mortality rate

r-Strategists

small, many offspring, don’t invest in offspring, mature early, short lifespans, reproduce once, low resource competition

K-Strategists

larger, less offspring, lot of parental care, mature slowly, longer lifespan, reproduce more than once, high resource competition