Summary
Similar-looking features with different origins that evolved independently for similar function, like bird and insect wings.
In depth
Wings of insects, birds and bats evolved independently. Their structure differs: insect wings are cuticle outgrowths, bird wings are feathered forelimbs and bat wings are skin stretched over elongated fingers. They result from convergent evolution due to similar selection pressures.
Analogous traits can mislead classification.
Analogy arises from convergent evolution, where similar selection pressures lead to similar solutions. Other examples are the streamlined bodies of fish and dolphins, the camera eyes of vertebrates and cephalopods, and the succulent stems of unrelated desert plants. Analogous traits can mislead classification if mistaken for homologies.
Distinguishing the two uses position, development, structure and comparison with outgroups, today supported by gene sequences. A structure can be homologous at one level and analogous at another: bird and bat wings are homologous as forelimbs, but analogous as wings.
Key idea: analogous traits share function and not ancestry.
Frequently asked questions
What is Analogous Structures?
Similar-looking features with different origins that evolved independently for similar function, like bird and insect wings.
Which area of biology covers Analogous Structures, and how advanced is it?
Analogous Structures is one of the 53 topics in Evolution. It is rated Beginner, so it suits learners who are starting out in biology. Related topics in this area include Homologous Structures, Convergent Evolution, Divergent Evolution.
Can you give an example of Analogous Structures?
The eyes of squid and vertebrates are similar but evolved separately.
What should I learn before Analogous Structures?
Analogous Structures is a Beginner topic, so no earlier topic is required. Other Beginner topics in Evolution that pair well with it include Evolution, Natural Selection, Charles Darwin.
What topics are related to Analogous Structures?
The closest topics to Analogous Structures are Homologous Structures, Convergent Evolution, Divergent Evolution, Vestigial Structures. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Analogous Structures?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Analogous Structures. To practise the whole of Evolution, use the Evolution quiz.
How is Analogous Structures different from Homologous Structures?
Analogous Structures: Similar-looking features with different origins that evolved independently for similar function, like bird and insect wings. Homologous Structures: Body parts with similar structure from a common ancestor but different functions, like a human arm and bat wing. Read both side by side and note what each one explains.
How should I study Analogous Structures step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Homologous Structures and explain the difference aloud. Finally, take the Evolution quiz and come back to this page for any question you miss.