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?