Population Sampling, Distribution, and Demographic Patterns

All flashcards

What is population size?

The total number of individuals belonging to a population in the area being studied.

What is population density?

The number of individuals per unit area or volume. It describes how concentrated a population is, not simply how many individuals exist in total.

What is a quadrat, and when is it useful?

A quadrat is a square frame that defines a sample area. Researchers count organisms within randomly placed quadrats, especially when studying plants or small, slow-moving organisms.

How does mark-and-recapture estimate a population?

A first sample is captured, marked, and released. After mixing, a second sample is captured; the fraction of marked individuals in that sample is used to estimate the total population.

What equation is used for a basic mark-and-recapture estimate?

Use $N \approx (M \times C)/R$, where $M$ is marked in the first catch, $C$ is the total in the second catch, and $R$ is marked individuals recaptured.

Quiz questions

1. How can population size influence a population's capacity to adapt?Answer: It can affect the amount of genetic variation available.
2. What information does a life table organize?Answer: Survival and mortality data for different age intervals.
3. Which mortality pattern is characteristic of Type II survivorship?Answer: The chance of mortality is roughly constant throughout life.
4. Researchers mark 60 animals, then catch 90 animals in a second sample, including 15 marked ones. What population size does the estimate give?Answer: Approximately $360$, using $N \approx (60 \times 90)/15$.
5. Which process can produce a uniform distribution of individuals?Answer: Territorial behavior that spaces individuals apart.