L5:Population Dynamics Flashcards
A group of individuals of the same species occupying a given area
Can be described through its characteristics such as:
Density (Number/area)
Distribution/Dispersion
Numbers (size)
Age Structure
Pertains that population’s growth depends on the resources of the environment
Limits to Growth
Focuses on the study of populations of organisms within a particular species and their interactions with the environment.
POPULATION ECOLOGY
It involves the examination of factors such as population size, population density, population growth rates, distribution patterns, and the factors that influence these parameters.
POPULATION ECOLOGY
The study of the size and distribution of biodiversity over space and time
BIOGEOGRAPHY
Aims to reveal where organisms live, and at what abundance
BIOGEOGRAPHY
The study of the vital statistics that affect population size
DEMOGRAPHY
Birth (Natality), Death (Mortality), Immigration, Emigration
DEMOGRAPHY
These 4 processes collectively determine the population’s growth or decline.
__
__
__
__
Birth (Natality)
Death (Mortality)
Immigration
Emigration
processes collectively determine the population’ size:
Number of individuals added through reproduction
NATALITY
processes collectively determine the population’ size:
Number of individuals removed through death
MORTALITY
In Natality:
births per 1000 refers to?
Crude Birth Rate
In Natality:
Average number of children born alive per woman in her lifetime refers to?
Total Fertility Rate
In Mortality:
Crude Death Rate refers to?
deaths per 1000
Refers to Average number of children born alive per woman in her lifetime
TOTAL FERTILITY RATE
Number of individuals in a specific area (or volume) of habitat (i.e. individuals/ km2; individuals/ mL)
DENSITY
Dependent on distribution and dispersal patterns
DENSITY
In Density,
It refers to (no further classifications, i.e., no idea how many males or females; no info on how many are in the pre-reproductive category, etc.) – information is more useful if combined with distribution data
-total number of individuals or biomass per unit of the total space
Crude density
What are the three patterns of distribution in populations of organisms:
uniform
random
clumped
Distribution Pattern:
Not as common
May happen when there is competition
Resources are scarce
UNIFORM
Distribution Pattern:
Quite rare
Hard to determine as truly random or clumpy
Less competition due to availability of resources
RANDOM
Distribution Pattern:
Most common type
More individuals will be present in areas that are favorable to them
Resources are clumped
Clumped
Distribution Pattern:
Territorial birds, such as penguins, tend to have __ distribution.
uniform
Distribution Pattern:
Plants with wind-dispersed seeds, such as dandelions __ distribution.
Random
Distribution Pattern:
Animals, such as elephants, that travel in groups exhibit tend to have __ distribution.
clumped
___ & ___ are useful measures for characterizing populations. Scientists gain additional insight into a species’ biology and ecology from studying how individuals are spatially distributed
Density and size
There are __ kinds of Factors affecting distribution. They are:
____
2;
Density Dependent
Density Independent
Kind of Factor Affecting Distribution:
limiting factors become more intense as population size increases; usually biological in nature
Density dependent
Kind of Factor Affecting Distribution:
factors unaffected by population density; usually physical in nature
Density independent
Competition for Resources
Predation
Parasitism
Infectious Disease
are example of _____ factor affecting density distribution.
Density dependent
Floods
Hurricanes
Unseasonable weather
Fire
Clear-cutting
Pesticide spraying
are example of _____ factor affecting density distribution.
Density Independent
Give the formula of population Change:
POPULATION CHANGE = (births + immigration) – (deaths + emigration)
Note: Rule of 70: To calculate the doubling time for a population in years, divide 70 by the percent growth rate ®
Population Size:
Populations ____through births (B) and immigration (I)
Populations ____through deaths (D) and emigration (E)
Increase
Decrease
Divides population into age categories or ecological age groups
Population Age Structure
In population age structure, _____ add individuals only to the base of the pyramid, and ____ only removes individuals from the population at all ages after birth.
births;
death
What limits population growth?
Resources competitors in terms of:
___
___
___
___
Biotic potential (r)
Environmental resistance
Ecosystem carrying capacity (K)
Rate of increase
Biotic potential refers to?
Ability of population to increase under ideal environment.
As with other organisms, this is and always has been a survival strategy against food deprivation, predation, and parasitism
Rate at which a population would grow if it had unlimited resources
Maximum rate of increase per individual under conditions with no environmental pressures to the population
Biotic Potential (r)
In nature, ___is rarely reached
biotic potential
The following contributes to _____
-lack of food or nutrients
-lack of water
-lack of suitable habitat
-adverse weather habitat
-predator
-disease
-parasites
-competitors
Environmental Resistance
The following contributes to _____
-reproductive rate
-ability to migrate or disperse
-ability to invade new habitats
-defense mechanism
-ability to cope with adverse conditions
Biotic Potential
maximum number of individuals that can be sustained in a particular habitat
Carrying Capacity (K)
Determined by limiting factors which affect the amount of resources available
Carrying Capacity (K)
occurs when population size is limited by carrying capacity
striving for dynamic equilibrium
deals with density dependent controls
Logistic growth
population expands by increasing increments
the more individuals
there are to reproduce
overshoot is usually followed by a crash
dramatic increase in deaths
Exponential growth
striving for dynamic equilibrium and deals with density dependent controls
OVERSHOOTING CAPACITY
overshoot is usually followed by a __. A dramatic increase in deaths.
crash
This can happen due to various factors such as rapid reproduction, immigration, or the availability of abundant resources. As a result, the population may experience a period of rapid growth and expansion.
OVERSHOOTING CAPACITY
In overshooting capacity, because the environment has finite resources, this period of rapid growth is often followed by a __ in population as resources become___. It can occur due to increased competition for resources, environmental degradation, disease, or other factors that limit population growth.
decline;
scarce
Patterns of timing of reproduction and survivorship Can be summarized in __
SURVIVORSHIP CURVES
There are three main types of survivorship curves namely ___,___,___
Type I – late loss
Type II – constant loss
Type III – early loss
-Rectangular survivorship on semilogarithmic plot: little mortality until old age, then fairly steep mortality
-Typical for top consumers (i.e., large mammals, humans), many annual plants
-Some very small organisms (i.e., predatory protozoa and rotifers
TYPE I (Late Loss)
-Diagonal line: relatively constant death rates with age
-The probability of death of organism is generally unrelated to age
-E.g., birds – die from accidents, poisoning, and other factors
TYPE II (Constant Loss)
- Inverse hyperbolic: extremely steep juvenile mortality, then relatively high survivorship afterward
i.e., organisms at the base of the food chain
i.e., many plant & tree species, fish, marine invertebrates & most insects
TYPE III (Early Loss)
What are the reasons for die-back?
Catastrophic Loss of Resources
Introduction of New Predator
Disease
condition observed in plants where sections of a plant, or sometimes the entire plant, experience a progressive decline in health and vigor, leading to the death of branches, shoots, or even the entire plant over time.
Die-back
