Describing Natural Selection of Native Species' Adaptations

Please choose one of the following species from the Corona, CA area. Then choose a single adaptation (structural, behavioral, or physiological) that this species has and describe how it may have developed according to Darwin's five ideas. Write a paragraph using the following guidelines:

1) Say which species and adaptation you have chosen.

2) Describe how this particular adaptation is an advantage to the species.

3) Use Darwin's 5 ideas to explain its development from ancestors of the species:

A) There was overproduction of offspring.

B) There was variation for this trait in the population.

C) There was a struggle for existence as members of the population with and without this adaptation competed for resources (food, water, shelter, and mates).

D) Individuals that had this trait survived more often than those without the trait because they were better suited to the environment.

E) Survivors reproduced and passed the genes controlling this successful trait on to their offspring.

4) Describe the type of natural selection this evolutionary change is an example of.

5) Draw a graph showing the change in the bell curve for this adaptation.

***Please use the above numbers and letters in your paragraph to help the peer evaluator grade your writing.

Example paragraph:

1) I am going to describe how cottontail rabbits got the length of legs that they have today. 2) Cottontails have medium sized legs that allow them to run from predators with good speed. This medium length also allows them to make sharp cuts to the right or left if the predator is faster and about to catch them. The legs are short enough that they are not clumsy and allow the rabbit to easily get into small places to hide after successfully evading predators. 3) Darwin would describe the development of this trait by saying that A) the rabbits overproduced offspring. Their ability to make babies was greater than what the environment can support. B) Within the population there was variation in rabbit leg length. Some rabbits had longer legs, some shorter legs, but most had medium legs on the bell curve. C) Rabbits struggled for resources that included food, good hiding spots, and mates. D) The medium length legs allowed the rabbits to get away from predators, get into good hiding spots, and were considered sexy by most members of the rabbit population. They survived at a greater rate than the longer-legged clumsy rabbits and the shorter-legged slow and not so sexy rabbits. E) The medium legged survivors reproduced like bunnies and populated the Corona area with their offspring.

5) Graph showing selection of mid sized rabbit leg length is stabilizing selection.


stabilizing selection
shorter                                                                                    longer
Rabbit Leg Length

Peer Evaluation:

Item to Grade Possible My
Eval 1
Eval 2
1) Statement written saying the name of the organism (+1) and the adaptation (+1) chosen.
2) Statement describes how having this adaptation is an advantage to the population (+2).
3A) Statement that the population of the species overproduces offspring (+2).
3B) Statement that there is variation in the population for that particular trait (+2). Also describes briefly what the variations options are (+2).
3C) Statement that there is competition or a struggle in the population for resources (+2). Also describes briefly what those resources are (+2).
3D) Statement that individuals with the trait were the fittest to the environment and survived at a higher rate than those without the trait (+2). An explanation is given as to how the trait helped them survive and have an advantage (+2).
3E) Statement that survivors were able to make babies / reproduce and pass on the great trait (+2)
4) The trait's evolution is correctly classified as either directional, stabilizing or disruptive selection
5) A graph is made correctly illustrating the change in the bell curve for this trait's frequency. Y-axis labeled "frequency" (+2), X-axis labeled with the variation options in the trait (+2), several bell curves drawn showing the change in frequencies over time (+2).
Writing is done with good spelling and sentence structure that is understandable 0 = no way, 1 = small problems, 2 = outstanding.