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Science - Biology
Standard 5 Objective 2
1 class periods of 70 minutes each
Through activity, lecture/discussion and a paragraph summary, students will understand that imperfections in organisms are an evidence for evolution. They will relate this to changes of populations over time and explain them by evolutionary process.
Students should be careful with the blocks and screws. They should be sure not to damage tables, floor, books etc when trying to get their screw/nail in the wood. CAUTION students against doing anything that might cause damage or injury to anyone or anything.
Duration: 1 ½ class periods (70 min.)
Students should understand inheritance and environmental pressures for evolution. They should also understand the definition of evolution.
More obvious contrivances are often less efficient, even awkward, typically still resemble their original structure, and are not "perfectly" adapted to their new job; they are adaptive compromises. Some are obviously re-tooled versions of other structures. Many clearly show their contrived nature; they are really poor (and hardly ideal) design solutions. They seem to challenge the popular notion that all living things are the product of intelligent design. We call these "contrivances", or sometimes "imperfections" since they clearly are imperfect. a good example would be the radial sesamoid wrist bone of a panda being used as a sixth digit "thumb".
Another class of imperfections (and therefore poor design) makes its appearance in the form of structures with no clear function, often reduced in size from their counterparts in other (or earlier) species. The origins of these, too, can be traced through their comparative embryological and evolutionary development. If these reduced features commonly appear in all or most individuals, we call them "vestigial" structures (example: our "wisdom" teeth). If they appear only rarely, they are called "atavisms" (example: tail on newborn human). If you like, you could add the term "imperfections" to encompass the last 3 categories.
Answer Key to Table:
SOME ADAPTATIONS & IMPERFECTIONS
REMEMBER, THE EMPHASIS HERE: Notice the MANY IMPERFECTIONS in living things (not so much their categories the definitions are not as important); are these most likely the result of poor design, poor engineering, or normal evolution?
Lesson Design by Jordan School District Teachers and Staff.