Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
5 Cards in this Set
- Front
- Back
|
How do ecologists study populations? |
Study of: • Numbers of individuals • Density • Distribution • Structure (sex, age) • Rates of natality and mortality • Factors that affect growth |
|
|
How do ecologists study populations? |
• A population consists of all the individuals of a species in a given area and usually isolated to some degree from other similar groups • Population structure describes the age distribution of individuals, and how those individuals are spread over the environment • The number of individuals per unit area or volume is the population density • Density has strong influence over how individuals react with one another and with populations of other species • Population structure changes over time due to demographic events: births, deaths, immigration and emigration • These events create population dynamics-> their study = Demography |
|
|
Characteristics of populations |
• Density - number of individuals/per unit area or unit volume • Spacing - dispersion • Growth rate Total population per unit of area Population density depends on: • Interactions with the environment • Quality of habitat • Density depends factors • Density independent factors |
|
|
Characteristics of populations |
• Carrying capacity is the maximum number of organisms that can be supported in a given habitat • Population size can be measured by several sampling techniques N1 = N0 + B - D + I - E N1= popn. In current generation, N0= popn. In previous generation, B= births, D= deaths, I= immigrants, E= emigrants • If these counts are made over many time intervals, we can determine how population density changes over time |
|
|
Spacing and distributions |
• Clumped- patchy distribution of resources • Uniform/Spaced- territorial species • Random- random distribution of resources |
