Question

Which of the following methods will tell an ecologist about both the size and density of a population?

a. mark and recapture

b. mark and release

c. quadrat

d. life table

Short answer

The Correct Answer is Option (c) Quadrat

Step-by-step solution

Introduction

A population is determined by two factors: population density and population size. Populations with a small number of persons may be dense or sparsely distributed in a given location. Because of the amount of genetic variation in the population, population size may affect the ability to adapt. Population density influences individual relationships within a community, such as food competition and individuals' capacity to find partners. The distribution of smaller species is denser than that of larger organisms.

Reasons for the Incorrect options

Counting all of the people in the area is the most accurate technique to measure population size. However, when studying huge areas, this strategy is usually neither logistically nor economically practical. As a result, scientists typically research populations by sampling a representative piece of each habitat and inferring about the population as a whole from this sample. The sampling procedures used to measure population size and density are usually adjusted to the characteristics of the organism being researched.

• A technique known as mark and recapture is commonly employed for smaller mobile organisms like animals. This method entails marking a sample of captured animals in some way and releasing them back into the environment to mingle with the rest of the population; scientists then collect a new sample and count how many of the marked animals are present in the new sample. Because they will have mixed with more unmarked individuals, this strategy believes that the greater the population, the lower the percentage of marked organisms that will be recovered. Mark and release are two terms that could be used to describe the same thing.
• Life tables are useful for learning about the life history of an organism and the life expectancy of persons of various ages. They're based on actuarial tables, which are used to calculate human life expectancy in the insurance industry. Life tables can include the likelihood of each age group dying before their next birthday, as well as the percentage of surviving individuals dying at each age interval.

Reason for the Correct option

A quadrat can be employed for static organisms like plants, as well as very small and slow-moving species. A quadrat is a square of wood, plastic, or metal that is placed on the ground at random and used to count the number of people who are inside its bounds. To get an exact count with this method, the square must be placed at random spots across the habitat enough times to get a good estimate. This method of counting will give you an estimate of population size and density. The number and size of quadrat samples are determined by the type of organisms and the distribution pattern.