91Ó°ÊÓ

Which technique for gathering data (observational study or experiment) do you think was used in the following studies? (a) The Colorado Division of Wildlife netted and released 774 fish at Quincy Reservoir. There were 219 perch, 315 blue gill, 83 pike, and 157 rainbow trout. (b) The Colorado Division of Wildlife caught 41 bighorn sheep on Mt. Evans and gave each one an injection to prevent heartworm. A year later, 38 of these sheep did not have heartworm, while the other three did. (c) The Colorado Division of Wildlife imposed special fishing regulations on the Deckers section of the South Platte River. All trout under 15 inches had to be released. A study of trout before and after the regulation went into effect showed that the average length of a trout increased by \(4.2\) inches after the new regulation. (d) An ecology class used binoculars to watch 23 turtles at Lowell Ponds. It was found that 18 were box turtles and 5 were snapping turtles.

Step by step solution

01

Understanding Observational Study vs. Experiment

An observational study involves collecting data without manipulating the environment or conditions. In contrast, an experiment involves manipulating one or more variables to determine their effect on some outcome.

02

Analysis of Study (a)

For study (a), the Colorado Division of Wildlife simply netted and released fish to observe what types were present. There was no intervention or manipulation of variables. This is an observational study.

03

Analysis of Study (b)

In study (b), the wildlife division actively injected sheep with a medication to prevent heartworm and then observed the effect. This manipulation of the variable (use of injection) makes it an experiment.

04

Analysis of Study (c)

Study (c) involves imposing a regulation (a form of intervention) and then observing the effect on the trout's average length. As a variable is manipulated (fishing regulation), this is an experiment.

05

Analysis of Study (d)

For study (d), the ecology class merely observed the types of turtles present at Lowell Ponds using binoculars without altering any conditions. This makes it an observational study.

Unlock Step-by-Step Solutions & Ace Your Exams!

• Full Textbook Solutions

  Get detailed explanations and key concepts

• Unlimited Al creation

  Al flashcards, explanations, exams and more...

• Ads-free access

  To over 500 millions flashcards

• Money-back guarantee

  We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Observational Study

In an observational study, researchers gather data without altering the conditions of the study subjects. They watch and record outcomes as they naturally occur, making no attempts to influence the study environment. This approach is helpful when the goal is to understand the existing state of a population or phenomenon. Observational studies are ideal when manipulation isn't possible or ethical. For instance, studying the behavior of wild animals often falls under this category since it is crucial not to interfere with their natural activities.

This type of study often involves methods such as:

• Watching: Observing from a distance to gather data.
• Recording: Collecting quantitative or qualitative data based on what is observed.
• Surveying: Asking subjects questions to collect necessary information without changing their environment.

In the context of wildlife, observational studies are essential. They provide insights into habits, populations, and environments without human intervention. Examples include counting animal populations or noting behaviors, like those seen in study (d) with turtles, where no variables were changed.

Experiment

Experiments involve actively changing one or more variables to determine the effects of these changes. Unlike observational studies, an experiment is marked by its intervention, which aims to establish causal relationships. This means the researcher deliberately influences conditions to observe the impact on the subject.

Key components of experiments can include:

• Manipulation: Deliberately changing conditions or variables to test their effects.
• Control Group: A group that does not receive the experimental treatment, acting as a baseline for comparison.
• Random Assignment: Ensuring subjects are randomly assigned to test or control groups to minimize bias.

Experiments provide clear, actionable insights because of their structured approach. In wildlife studies, while more ethically complex, they can provide robust evidence of cause and effect. For example, study (b) is an experiment because it involves administering a treatment (heartworm injection) to sheep and observing the results, unlike passive observation.

Wildlife Studies

Wildlife studies aim to understand various aspects of animal populations and their ecosystems. They can employ both observational studies and experiments to gather data, depending on the question being addressed.

Types of wildlife studies might involve:

• Population Monitoring: Tracking changes in animal populations or distributions over time.
• Behavioral Observations: Understanding the natural actions and interactions within animal groups.
• Environmental Impact Assessments: Studying how changes in the environment, such as new regulations or habitat alterations, affect wildlife.

In the provided scenarios, wildlife studies include both observational studies and experiments. Study (a) and (d) involved the observation of fish and turtles, respectively, to understand their current population without altering their environment. Study (c), on the other hand, employed an experimental approach by imposing fishing regulations to note changes in trout size, illustrating how researchers can manipulate conditions to assess the impact on wildlife.