Homologous structures are structures which are similar even in widely differing species. It is evidence of divergence from a common ancestor. The form is similar even though the function may not be. Tool userRunnerPouncerFlyersSwimmer itc.gsw.edu/.../histgeol/paleo2/homol1.htm
http://www.press.uchicago.edu/books/gee/carroll4.html The ancestor started with four primitive but functional wings. How have the form and function diverged in contemporary insects?
http://evolution.berkeley.edu/evosite/lines/images/homology.gif The pitcher plant and venus fly trap live in environments with poor soil and need extra nutrients. The poinsetta has to attract insects in order to promote pollination. The cactus has to protect its moisture from pests. Describe a possible variation as a first evolutionary step from a regularly shaped leaf toward each of these specialized homologous structures.
Describe the form and function of the pictured structures (antennae and leg). Compare them, and use the vocabulary word homologous in your sentence. http://8e.devbio.com/article.php?ch=18&id=178