Homologous and Analogous Structures - Purdue University · Two structures are considered to be...
Transcript of Homologous and Analogous Structures - Purdue University · Two structures are considered to be...
Homologous and Analogous
Structures
1. How does comparative morphology
provide evidence for evolution?
2. What can the presence of homologous
structures signify?
3. What can the presence of analogous
structures signify?
A study of the configuration or the
structure of animals and plants.
http://www.dallasnews.com/sharedcontent/dws/news/nation/stories/DN-
bats_09tex.ART.State.Edition2.432418c.html
http://votebits.com/explore-the-world-of-marine-animals/whale/
Two structures are considered to be
homologous is they have the same
structure; may be used for different
functions.
Two structures are considered to be
analogous if they have the same function,
but not the same structure.
Similar body parts that reflect shared ancestry.
May be used for different purposes in different groups, but the same genes direct their development
A body part that appears very different in appearance may be quite similar in underlying parts.
This indicates a shared ancestry.
Wings that have similar function but
different structure.
Similar structures that evolved separately
in different lineages.
http://news.nationalgeographic.com/news/2011/04/pictures/110407-science-fossils-insects-bugs-mayflies-mayfly-flying/
http://t2.gstatic.com/images?q=tbn:ANd9GcQWBP7aGyaHzETq76PnDkDbOfbbjpSpl3I5foQjvQTWgOzyIvrJ7A
Above shows how alike the structures are of
arms in different species http://sbi3uevolution.wikispaces.com/Analogous+structures
Homologies and Analogies
This is an online activity with a handout to
complete.
You will have 30 minutes to complete this
activity. Open the website and complete the
handout as you move though the pages. When
you are finished, turn your handout in to the
instructor.
In your science journal answer the following questions. Each question will require you to use appropriate vocabulary learned in this session. You may use your book to help you answer the questions. Each answer will require a minimum of 75 words.
1. How does comparative morphology provide evidence for evolution?
2. What can the presence of homologous structures signify?
3. What can the presence of analogous structures signify?
Think of two animals that have parts
which have similar structures , but have
very different functions.
• What are the two animals?
• What parts do they have that are similar?
• What function does each part have that is
different?
Think of two animals that have parts
which do the same thing, but have very
different structures.
• What are the two animals?
• What do they do that is similar?
• What structure does each one have that is
different?