Lecture 24- Population Ecology Flashcards
How is ecology defined?
Branch of biology that studies the interactions between living organisms and their physical environment
How is population ecology defined?
Branch of ecology that studies the processes (dynamics) that affect the distribution and abundance of organism populations (study of change in populations)
What does the formula B=bN imply about a population?
The expected number of births per year in a population size of N (expected number of births= per capita birth rate times population size)
What is the intrinsic rate of increase?
Maximum rate at which a population could increase under ideal conditions (r max)
Which mechanisms can increase the size of a population?
Birth and immigration
What is an r-selected species?
Species that maximize reproduction rate and usually exhibit life history traits such as early maturity, large number of offspring, short lifespan, and little parental care
What does the formula D=mN imply about a population?
Average likelihood of deaths per year in a population size of N (expected number of deaths= per capita mortality rate times population size)
What is the shape of the curve of a logistic growth model?
Sigmoid (S-shaped)
Which mechanisms can decrease the size of a population?
Deaths (mortality) & emigration
What can be inferred about a population of the per capita rate of change (r) is less than 0?
Population is shrinking
With regards to a logistic growth model, what can be inferred about a population is the value of N is very small?
Small N results in a (K-N)/K value close to 1 which implies a rapid growth rate
What does population growth in nature not follow a perfectly logistic curve?
Populations tend to fluctuate around carrying capacity/ environmental changes/carrying capacity may change
How is population density defined?
Population per unit area (volume in sea)
In what type of environment would an r-selected strategy be favorable?
Variable/ unpredictable environments
What can be inferred about a population if the per capita rate of change (r) is greater than zero?
Population increasing
What are the two main categories of factors that influence population size?
Density-dependent factors & density-independent factors
How is carrying capacity (K) defined?
Largest population that can be maintained for an indefinite period by a particular environment
What can be inferred about a population if the per capita rate of change (r) is equal to zero?
Zero population growth (ZPG)/no net change/dynamic equilibrium
What is iteroparity?
Reproductive strategy in which organisms are capable of having offspring many times over the course of their lives
Under what conditions would a population follow an exponential growth model?
When every member of a population reproduces at physiological capacity (idealized and theoretical)
With regards to a logistic growth model, what can be inferred about a population if the value of N is close to K?
As the value for B approaches the value for K, the value for (K-N)/K approaches zero which implies a slow population growth rate
What are some limitations to the exponential growth model?
Environmental resistance/buildup of toxic wastes/limited food, resources, and living space
What is semelparity?
Reproductive strategy in which an organism only reproduces once before death
What is a k-selected species?
Species characterized by having only few offspring, but investing high amounts of parental care
