A Little Bit More
As adults, fleas feed upon the blood of birds and mammals. A few are vectors (carriers) of disease but most are just annoying. Host preference varies tremendously in different species of fleas. With some, there is a close association with a particular host, whereas with others, a broad number of host species will do.
The flea does not always remain on its host but may actually spend most of its time away from its food source. The adult female usually leaves the host to lay eggs either in the dirt or in the host’s home quarters. The eggs hatch into tiny, whitish, legless larvae feeding upon organic debris and on the feces of adult fleas. Once the immatures are fully developed as larvae, they spin a cocoon and pupate. The flea remains in this pupal stage from one month to half a year before it emerges as an adult.
It is interesting to note that it remains as a pupa until a loud noise or jolt stimulates or “awakens” the flea to emerge. This explains why vacationers, returning after some time to an empty house, are descended upon by a horde of hungry fleas. Their sudden return causes the waiting flea pupae to emerge simultaneously, ready for their first meal. Historically, wealthy Romans were aware of this phenomenon and would have their slaves enter their home first so they, not the owners, would attract the attention of these biting insects!
Definitions
Debris (de-BREE): remains of something broken down or destroyed
Feces (FEE-cees): bodily waste, excrement
Activities
If I Could Jump Like a Flea
Objectives: Use math to make an animal's jumping ability more relevant
Materials: Meter or yard stick, paper and pencil
In this activity, your students should be able to determine just how far they could jump if they could jump like a flea. Although almost the entire world has gone metric, the United States seems reluctant to accept the inevitable. Converting from English to metric is a good math exercise for your students and maybe soon, even U.S. citizens will be using the metric system exclusively. You may need to provide conversions from English to metric for your students if they haven’t already worked with the metric system.
There are 25 millimeters (mm) in an inch
There are 2.5 centimeters (cm) in an inch
There are 30 centimeters (cm) in a foot
There are .9 meters (m) in a yard
An adult Dog Flea is 2mm long and can jump 200 times it’s own body length. How far can a Dog Flea jump and how far could you jump if you had this same ability?
1. Have your students figure out how many millimeters a Dog Flea can jump and then have them convert that to inches.
2. Have them draw a 2mm line on a piece of paper, lay that paper on a table or floor and then measure out the possible jumping distance of their flea from paper to landing spot using the metric system.
3. Now have your students measure their own height in meters (work in pairs so one student can measure the other against a wall or door frame).
4. Using each student’s height, have them determine what the jumping distance would be if they were capable of jumping as far as a Dog Flea can jump.
5. Now have each student lay out that distance in actual meters along the corridor that they would be able to leap if they were a flea. This makes a very graphic demonstration of a flea’s jumping ability and is sure to impress everyone!
Key Concepts
Adaptations and Diversity, Identification, Structures and Functions
Questions
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