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## Biology Graphs - Predator and Prey

This is a*phenomenon*reviewed for the following learning goal:

Given adequate resources and an absence of disease or predators, populations of organisms in ecosystems can increase at rapid rates. Finite resources and other factors limit their growth.

## Summary

This graph shows the numerical relationship between the population growth of predator (lynx) and prey (hare) over a 90 year period. Text questions probe student thinking about this relationship and other factors that may impact the population of the hare and the lynx. It addresses the part of the key idea about the rapid rate of increase in the population size of organisms in ecosystems with a lack of predators and adequate resources. This is *likely to be comprehensible *to middle school students. The complexity of the graph may result in misinterpretations of the information contained in the graph.

**Limitations**:

*Class interpretation of the graph would provide the same information to all students about the relationship between the population growth of the hare and the lynx.*

**Suggestions to improve effectiveness**:## Detailed Review

### Description

The phenomenon is the numerical relationship between the population growth of predator (lynx) and prey (hare) over a 90 year period as shown in a graph. The graph shows that as the population of hares increases, the population of lynx increases. As the population of lynx continue to increase, the population of hares decreases. Questions probe student thinking on this relationship and other factors that may impact the population of the hare and the lynx.

**Resource Copyright Owner:**AlgebraLab**Type of Resource:**text/html

## Content alignment

The resource addresses the actual substance of the learning goal rather than just the topic.

### Explanation

This resource addresses the numerical relationship between population growth over time of a predator (lynx) and prey (hare) populations in an ecosystem. Close examination and careful interpretation of the graph reveals the possibility of other factors affecting the population growth of the lynx and the hare, but the other factors are not specifically identified.

## Scope

The resource addresses the indicated part of the learning goal:

### Explanation

[Given] adequate resources and [an absence of] disease or [predators, populations of organisms in ecosystems increase at rapid rates.] Finite resources and [other factors limit their growth.]

## Sophistication

The resource correctly reflects the level of sophistication of the learning goal.

### Explanation

Vocabulary and parameters of the graph are age appropriate for middle school.

## Notes for Teachers

The user can encourage the students to examine the graph carefully, as there are instances where there appear to be other factors impacting the population growth of the lynx and the hare. With the questions provided at the site that probe for student thinking, the student can be guided to the understanding that there are more complex interconnections affecting the population growth of various organisms in an ecosystem beside the linear predator / prey relationship. Other factors such as disease, competition for limited resources, and the interrelationships in a more complex food web may be considered, thus increasing the level of alignment to the learning goal.

## Quality of instructional support

** Is the relationship between the phenomenon and the learning goal made clear? **

Yes—The relationship between the phenomenon and the learning goal is made clear.

This graph clearly shows the numerical relationship between the population growth of predator (lynx) and prey (hare). As the population of the hare increases, the population of the lynx shows a corresponding increase. As the population of the lynx increases, the population of the hares decrease.

** Is the phenomenon likely to be comprehensible to students?**

Partial—The phenomenon may be comprehensible to students.

This graph addresses several misconceptions that students may have related to this learning goal. Students often think that communities change little over time, that populations exist in states of constant growth or decline, and that populations increase until limits are reached, then they crash and go extinct. The fluctuations in the population growth of the hare and the lynx represented in this graph address those misconceptions by showing that population growth varies over time. The complexity of the graph and possible difficulties reading and interpreting the graph may result in various interpretations, resulting in conclusion drawn from erroneous information.

** Is the phenomenon first-hand (when appropriate or practical) or
vicarious through use of video, pictures, or text?**

Partial—The phenomenon could be experienced more directly than the resource provides.

The phenomenon can be observed through a graph of data.

**Is the phenomenon efficient, i.e., the benefits justify the costs in time and money? **

Yes—The phenomenon is efficient: the benefits justify the costs in time and money.

The resource is free and available for immediate use.

Useful with modification## Notes to teachers

Class interpretation of the information shown in the graph would provide the same information to all students about the relationship between the population growth of the hare and the lynx.