HOMOLOGOUS STRUCTURE
IB Biology Grade 11
Clarissa Nitihardjo & Stella Sunarja
WHAT IS HOMOLOGOUS STRUCTURE?
A body part with a same structure between some groups of organisms due to inheritance from a same ancestor
Though not necessarily sharing the same function
Having homologous structure does not always have analogous structure
Analogous structure: different species with similar features in function but not necessarily in structure
WHAT IS THE IMPORTANCE OF HOMOLOGOUS STRUCTURE?
To provide a track of evolutionary paths Diverges between species and sub-
speciesHelps recognizing the same behavioral
characteristics which are modified in different subspecies by their environments
WHAT ARE THE EXAMPLES OF HOMOLOGOUS
STRUCTURE?
PENTADACTYL LIMBSPenta=fiveDactyl=digits
Bones of limbs of vertebrates are very similar
The functions of each forelimb are different
http://carrier.pbworks.com/Evolution-Fourth-Hour
VESTIGAL ORGANS Structures or organs that are not very
useful—vestigal Humans have tail bonesSome snakes have limb bonesSome salamanders have eyes (although
they are blind)
Vestigal organs usually are useful in other species
It can be viewed as an evidence of evolution: share common ancestors
EAR OSSICLES
Reptile: the stapes contacts the quadrate, which in turn contacts the articular
Mammal: the stapes contacts the incus, which in turn contacts the malleus
http://www.talkorigins.org/faqs/comdesc/section1.html.
BIBLIOGRAPHY 1. Analogous Structures. Biology Online. [Online] [Cited: September
20, 2010.] http://www.biology-online.org/dictionary/Analogous_Structures.
2. 29+ Evidences for Macroevolution. Talk Origins. [Online] [Cited: September 20, 2010.] http://www.talkorigins.org/faqs/comdesc/section1.html.
3. iscid. Homologous Structure. [Online] 2005. [Cited: September 18, 2010.] http://www.iscid.org/encyclopedia/Homologous_Structure.
4. unknown. Evolution. [Online] [Cited: September 18, 2010.] http://bioweb.cs.earlham.edu/9-12/evolution/HTML/live.html.
5. Allott, Andrew. Evidence for Evolution. Biology. New York : Oxford University Press, 2007, p. 37.
6. ExamplesOF. Example of Homolgous Structure. [Online] 2010. [Cited: September 18, 2010.] http://www.examplesof.com/language/homologous_structure.html.
7. Taylor, Stephen. Evolution. Science Video Recources. [Online] 2010. [Cited: September 18, 2010.] http://sciencevideos.wordpress.com/bis-ib-diploma-programme-biology/05-ecology-and-evolution/evolution/.
Top Related