Population Ecology Flashcards
What is demography?
The study of the statistics of a population and how they change over time
What two factors influence population size and what do they mean?
(Size is often estimated)
Density - number of individuals per unit area
Dispersion - pattern of spacing among individuals within a population
What are the three types of distribution?
Clumped - individuals clumped together
Uniform - even throughout
Random - scattered distribution
In wild populations, individuals most often show a _____ pattern of dispersion.
A) Uniform
B) Clumped
C) Random
D) Dispersive
B
Resources are often clumped, and they need others to reproduce
What are three factors small populations are at risk of facing?
Inbreeding depression (offspring defects), genetic drift (loss of genetic material), and extinction
What 4 things can influence population dynamics?
Births (add)
Immigration (new ones coming in)
Emigration (individuals leaving)
Deaths (decrease)
What is carrying capacity?
A product of the environment, there is a maximum population that can be supported, which limits exponential growth to infinity. Populations reach carrying capacity.
What is a life history trait? What are 4 general examples?
Factors that influence the schedule of reproduction and survival.
Age at which reproduction begins, patterns of survivorship, how often an organism reproduces, how many offspring are produced
What is semelparity and iteroparity?
Semelparity - reproduce once and die (ex. annuals)
Iteroparity - produce offspring repeatedly (ex. perennials)
What is r-selection and k-selection?
r-selection: density-independent selection, many offspring, little parental investment. Good in low-competitive environments. (ex. dandelion)
k-selection: density-dependent selection, few offspring, great parental involvement. Good in environments near carrying capacity (ex. human)
A random human on earth dies. Guess their age.
A) 7
B) 25
C) 50
D) 80
D
The older a human is, the logistically closer they are to death.
What are the three types seen on a survivorship curve? What do they each mean?
Type 1 - young organisms survive, older ones are more likely to die. (Humans)
Type 2 - equally likely to die if you are young versus old. (Gophers)
Type 3 - Majority of offspring don’t survive early on. (Ex. Oak tree)
What environmental factors stop a population from growing indefinitely?
Physical space available, competition for resources, waste buildup, territoriality, disease, predation (both predator and prey)
What happens to predator and prey populations as they fluctuate?
They fluctuate together. As you see the rabbit population go up, so does the lynx population, and when rabbits decease becuase there are more lynx, the lynx population goes down. And so on.
What are some things about global human population dynamics?
Exponential increase in human population has started recently (modern era). But the rate of increase is starting to slow down.
What is the earths carrying capacity for humans? - Scientists estimate 10-15 billion people
Due to socioeconomic factors, there are variations in industrialized countries versus un-industrialized countries, such as differences in infant mortality and average life span.
