Population Dynamic Definitions Flashcards
population dynamics
the study of populations of organisms in a given area
Total Population Count (N)
number of individuals of a species in a specific geographical area
Population Density (D)
number of individuals per volume or area
D = ?
N/A = N/V
Direct Count
best for small, immobile populations (counting physically)
Transect
Best for low density populations
Count individuals in line or rectangle
Random start point and travel direction ensures random sampling
Quadrat
Best for larger, relatively immobile populations
Count individuals within small area and multiply to larger area
Sample sites are randomly selected
High remark means smaller population
Population = ?
(number originally marked) x (number recaptured) / (number marked recaptured)
Indirect evidence
provides an idea of relative density vs absolute density
counting indicators like nests and burrows and estimate
Relative density
comparing population in one area to that of another
Distribution pattern
How population is distributed within an area
Clumped Distribution
Organisms live in small concentrated groups, greater rates of survival in groups
ex schooling fish
Uniform Distribution
Organisms evenly spaced within an area, competition for resources and often territorial behaviour
ex wolverine
Random Distribution
Organisms distributed in a random pattern (plants with wind dispersed seeds)
Life History
describes the factors about a population, including survivorship and fecundity
Fecundity
Average number of offspring produced by a female member of a population over lifespan
Survivorship
number or percentage of organisms that survive to a given age
Type 1
High investment ensures high survival rate of offspring
low fucundity
long lifespan
mortality rate high at end
Type 2
Mortality risk constant through lifespan
Type 3
Little to no time or energy investment in survival of offspring
many offspring
short lifespan
mortality rate highest in early life
Unlimited Resource Enviornment
Ideal conditions with no food and unlimited resources
not common in nature
population will reach biotic potential (r)
will cause exponential growth
Crash eventually would happen bc runout
Biotic Potential
population reaching its highest per capita growth rate
Limited growth enviornment
common in nature
resources will limit growth
organisms will compete for available resources
birth and death rates will even out
will reach carrying capacity (K)
Carrying Capacity K
maximum population sustainable in a given environment
changes depending on environment
logistical growth
S shape of graph
for limited resource environment pop growth
r selected strategy
short life span
mature at young age
large number of offspring
little/no care of offspring
k selected strategy
long life span
mature later in life
produce fewer offspring
high level of parental care
Life strategies for max survival
reach reproductive maturity at a young age
long lifespan
large number of offspring
provide high levels of care for offspring
Changes in population
monitoring birth rates and death rate
immigration and emigration
Populaton changes formula
N = (B+I) - (D+E)
Population growth rate formula
gr = N/t
Per capita growth rate formula
cgr = N/N
Two main classifications
Density independent factors
Density dependent factors
Density independent factors
Abiotic
Does not matter pop density
Minor or major change in numbers
Ex floods, droughts, pollution
Density dependent factors
Biotic
Greater effect on larger population
Ex competition
Competition
When individuals compete for resources
Intraspecific competition
Interspecific competition
Intraspecific competition
Competition among single species
Interspecific competition
Competition between two or more species for the same resource
Competitive exclusion principal
Resource partitioning
Not always negative impacts
Competition exclusion principal
Species best able to thrive under given conditions will out compete the others
Resource partitioning
Species living in the same area use different resources in the same habitat
Reduces competition and improves survival rates
Positive impacts of Interspecific
Producer - consumer
(Flowers - bees)
Predator - prey
Cycle between high and low population
Sinusoidal growth curves
Defensa mechanisms
Used as protection against predators
Co-evolution, prey evolve then predator then again
Protective colouration, mimicry, camo, warning
Mimicry
Species that mimic each other either
Mullerian (both species have defense)
Batesian (one has defense but not the other)
Camouflage
Blending in w environment
Warning colouration
Colours and patterns warn danger
Symbiotic relationships
Close reaction between two species, symbiont and a host
Parasitism
Mutualism
Commensalism
Parasitism
One organisms harmed, other benefits
Ex salmon and sea lamprey
Mutualism
Two organisms work together and both benefit
Ex anemone and clownfish
Commensalism
One benefited and the other is unaffected
Ex orchid and trees
Keystone species
Large impact on most/all chain
Mass population growth happened when
In the last 200 years, exponential growth started in the 1800s during the industrial evolution
World population growth
Used to be steady
Currently in a period of rapid population (per capita growth, 1.1)
Rate of growth is declining and so is doubling time
Factors that contribute to population growth
Technological advancements
Agricultural advancements
Domestication of animals
Improved healthcare
Engineering advancements
Improved food storage and transportation
What do the factors serve to accomplish
Artificially manipulate earths carrying capacity of the human species
Population growth distribution
Most growth is in developing countries
Population starting to shrink in developed countries
Ecological footprints
Amount of land required to support one persons needs
Crop land
Grazing land
Fishing ground
Forest land
Carbon absorption land
Building area
Resource harvesting land
Where has larger eco footprint
Bigger in developed countries
Mostly energy and food production
Bio capacity
Measure of available resources on area or the whole earth
Population pyramids
Graphical description of a country’s population by sex and age
See overall characteristic, and potential to increase or descreste
Growth state
General shape of pyramid on graph
Kenya (rectangle)
Sweden (triangle)
Kenya (triangle)
Rapid growth, large portion going into reproductive years, low life expectancy
Sweden (rectangle)
Stable population (no big growth) even distribution of age groups, longer life expectancy
Waste disposal
As human population grows, so does waste production
Gaseous (air pollution)
Liquid (waste water, sewage)
Solid waste (garbage, limited space for landfills)
Ends up in water ways affecting aquatic life and water
Biodiversity
The variety of species that exist within and area or eco system
Greater biodiversity allows for better resilience
Resilience
Effective response against stressors like disease, climate change, and habitat shift
Human activities that are threats to biodiversity
Deforestation
Habitat loss from development of roads pipelines dams
Over exploitation
