ecosystems test Flashcards
what is symbiosis
relationships between organisms
what is commensalism
where one organism benefits and the other is neither harmed nor benefitted
what is mutualism
when both organisms benefit
what is parasitism
when one organism benefits and the other is harmed
how do ecologists study populations?
by examining their geographic range, growth rate, density and distribution, and age structure
what factors affect population growth
birth rate, death rate, and migration
what happens during exponential growth?
the larger the population gets, the faster it grows
what happens during logistic growth?
The population begins growing exponentially, it slows down, and then the rate of pop. growth reaches 0
_________ demonstrates how genetics and evolution influence each other
population genetics
How many factors change allele frequency within a population?
5
How does sexual selection change the population
Sexual selection changes the population because the traits that attract the most mates are going to show up more often in the Gene pool
Changes in allele frequency due to random chance is…
genetic drift
Changes in allele frequency due to mixing with new genetically different populations
Gene flow
What principle states that under the right circumstances Mendelian genetics works at the scale of a whole population
Hardy-Weinberg Principle
The Hardy-Weinberg equilibrium requires..
No natural selection, no sexual selection, gigantic population size, no mutations, no gene flow
What is the Hardy Weinberg equation?
p^2+2pq+q^2 (q= freq. of recessive allele, p = freq. of dominant allele)
What factors determine carrying capacity?
Limiting factors
What limiting factors depend on population density?
Density dependent factors like competition, stress, parasitism, disease, predation, and herbivory
What limiting factors do not typically depend on population density
Environmental extremes such as hurricanes, droughts, floods, natural disasters, and temperature
What is the relationship between limiting factors and extinction
If limiting factors causes the carrying capacity to fall low enough, populations can become extinct
Intrinsic growth rate is
whether the pop. is increasing or decreasing