1st Test Flashcards
Concerns
Ecological factors driving these dynamics; develop quantitative descriptions and models -> to make predictions
Population ecology
Sub discipline examining dynamics and structure of populations
Population
Group of individuals of one species within a particular area at a particular time usually use same resources and influence by the same environmental factors
Community
Group Of different species interacting
Population biology
Includes ecological and genetic concepts. Brings in genetic aspects of populations.
Population genetics view
Subdivided populations into local interbreeding groups (demes) “genetic neighborhood”
Gene pool
Total of all genes and their different forms within a population. Changes in a gene pool over time= microevolution often focus on one gene.
Alleles
Different forms of a gene. For a gene in an individual there can be two alleles ( two chronometer of each type- diploid)
Homogenous- if all alleles are the same AA of aa
Heterogenous- if genes are different Aa
Polymorphic- many alleles, no limit
Monomorphic- if only one allele in the entire pop gene “fixed”
Genetic structure -
pattern of frequencies of genotype and alleles in a pop.
Exogenous factors
(Aka extrinsic) things on the outside of pop. do not depend on pop. to occur. (External to the population) are considered to be density- independent.
-weather conditions- precipitation, temperature, climate
Endogenous factors
(Aka intrinsic) due to population itself, are considered density dependent factors. ( time lags in response to density, decline in reproduction output with increase in density ..) monarch - pathogen infection frequency depends on pop.size
High density in infraspecific competition
Density-dependent - increases for resources and or Space thus results in decreases in survival, growth and reproduction.
Intraspecific competition
A biotic agent within the species. Increasing in density (crowding) leads to decrease in survival, growth and reproduction
-a bit pricey agent of natural selection evolutionary consequences
Competitive ability
High competitive ability- high growth rates, ability to grow at low resource level, Etc…
Competitive effect
How strongly an individual can suppress growth and reproduction rates of other.
Competitive response
How little or much an individual is suppressed by neighbors.
It may not be apparent if an individual had an ability to dealing with stressful competitive env.
Asymmetric competition
Common in nature- larger individuals have great effect in smaller individuals and smaller have close to no effect on larger individuals
Floaters
Floaters without territories with numbers of territorial males.
Negative competition
“Inverse density- dependence” as density decreases population growth increases
Allee effect
If populations get too small probability of extinction had become unacceptably high. Allee proposed that all species have a minimum viable population (MVP) number varies with species.
Population fluctuations
Small, irregular
Some fluctuations mostly due to demographic stochasticity.
Lots of deaths and birth maintain somewhat balances pop size
Population fluctuation
Large, irregular
When the females and males are of the same age and are left to repopulate a species. Most females will be the same age and will hit their Unreproductive old age at the same time. Reproduction will stop until those females daughters become mature
Cyclical- population fluctuations
Regular fluctuations - predator- prey cycles of abundance a when prey pop increase so does predator-> than prey pop goes down and so does predator->the. Prey goes up ( that’s the cycle )
Irruption
Mostly low density but occasionally pop explosions (ex: mice and insects)
