Population Dynamics Flashcards
Define gene pool
The total of all alleles for all the genes in a population
What is the benefit of having a greater variety in a gene pool?
It allows a population to more easily adapt to changing environment
State the five Hardy-Weinberg conditions
- Very large population 2. No net mutation 3. Random mating 4. No natural selection 5. No migration
What does the Hardy-Weinberg principle measure?
The amount of genetic variation within a population
What can the Hardy-Weinberg principle identify?
If a population is in genetic equilibrium or microevolution
Mutation
Leads to new alleles in the gene pool, can give people a selective advantage. Back mutations can occur
Gene Flow
The net movement of alleles from one population to another.
Can increase diversity in nearby populations
Reduces genetic differences between populations
Non random mating
Selected individuals have a better chance of mating than other
Genetic Drift
Change in allele frequencies due to chance events
Bottleneck effect
A rapid decrease in a population size and only a few individuals are left to pass on their genes.
Leads to low genetic diversity
Natural Selection
Organism that survive pass on their genes increasing allele frequency
The environment gives some a selective advantage
Sexual selection
Species that mate with individuals having a particular trait
Heterozygous Advantage
Individuals that are heterozygous have a survival advantage over those that are either form of the homozygotes.
Define Habitat Fragmentation
Large continuous habitats that are split due to humans
Define Population density
The number of organisms in a given area
Define uniform distribution
Even distribution
Define Random distribution
Organisms are distributed with no pattern
Occurs where resources are abundant and there is little competition
Define clumped distribution
Grouped together in a certain area
List the four factors that affect population growth
Birth rate
Death rate
Immigration rate
Emigration rate
Define population explosion
Rapid increase in a population that happens too fast to be contained
Define population Crash
Rapid decrease in population
Define growth rate
Change in population over time
Define per capita growth rate
A measure of the change in a population over time while taking into account factors that affect population growth.
Define Biotic potential
The highest possible per capita growth rate
List the five factors that biotic potential is dependent on
Number of offspring per reproductive cycle
Number of offsprings that reach reproductive age
Age of reproductive maturity
Number of times the individual will reproduce
Life span of the individuals
Define carrying capacity
The theoretical maximum population size the environment can sustain over time
Define the lag phase
Slow population growth due to few individuals able to reproduce
Define Exponential Growth
Rapid population growth due to the higher birth rate than death rate
What stops exponential growth from continuing forever?
Competition and limiting factors
Define the stationary phase
When the birth rate is equal to the death rate
What is the growth pattern called and what’s the name of the curve?
Logistical and the curve is “S” shaped
Define Stable equilibrium
Fluctuations around the carrying capacity
Define Density dependent Factors
Biotic factors that limit the carrying capacity
Define Density independent Factors
Abiotic factors that limit the carrying capacity
Define environmental resistance
The total effect of all limiting factors
It prevents population from growing at its biotic potential
Define R-selected strategies
Species that reproduce close to their biotic potential
List six factors of r-selected strategies
Short life span Small in size Early reproductive age Many offsprings produced Competition is not significant Affected by density independent factors
Define K-selected strategies
Populations which live close to their carrying capacity
List seven factors of k-selected strategies
Larger animals Slower reproductive age Longer life span Older reproductive age less affected by environmental changes Fewer offsprings Affected by both density dependent and density independent factors
Define a open population
Populations that allow for immigration and emigration
Define a closed population
Populations that don’t allow for immigration and emigration
Define community
Interacting populations within a given area
Define intra specific competition
Competition within members of the saw species for resources
It is density dependent
Define Inter specific competition
Competition between members of different species for resources
What is the competitive exclusion principle
A principle that states that no two organisms can occupy the same niche in a community
Define invasive species
Non-native organisms that are introduced to an ecosystem that are harmful to native species
What are predator-prey interactions called
Boom and bust cycles
List three defences against consumers
Poor Taste
Physical protection
Camouflage
Define batesian mimicry
When harmless animals evolve to look like harmful; ones
Define mullerian mimicry
When 2 harmful animals evolve to look each other
Define symbiosis
A relationship between 2 species that live together
List and define the 3 symbiotic relationship
Parasitism- When 1 species benefits while the other is being harmed
Mutualism- When both species benefit
Commensalism- When one species benefits and the other is unaffected
Define Succesion
Change in an ecosystem over time
Define primary succession
Begins when no soil is present
Define pioneer communities
The first species to populate an area that produce soil and nutrients when they die
Define Climax communities
The stable community that eventually develops
Define secondary succession
Begins when soil is present but the old community has been destroyed by an ecological disturbance
Define sustainability
Meeting our current needs without compromising the future of the planet
What effect did the industrial revolution have?
Better living conditions
Improved agriculture
Improved medicine
Better hygiene
What effect did the industrial revolution have?
Better living conditions Improved agriculture Improved medicine Better hygiene Slowing the death rate
