[Music] homologus structures are anatomical structures that are similar structurally but they tend to have different functions let's take a look at a couple examples take a look at the arm of a human the leg of a cat leg of a horse wing of a bat and a flipper of a dolphin in the group you have different species but the anatomical structures look similar why would the bones in a dolphin's flipper have bones similar to what you Ed to grasp objects these are homologous structures similar Anatomy different functions notice that they are made up of similar bones each structure has a humorous two forearm Bones the radius which is in green and the Ona which is yellow metacarpal and fanges notice that the dolphin has five fanges just just like we have five fingers but also notice that each structure has a slightly different function the horse uses the structure to walk and run and the bat uses the structure to fly and again the dolphin uses it to swim homologous structures can be used to infer evolutionary relationships among organisms because the structures are similar with the human cat horse bat and dolphin it is easy to infer that they all came from a common ancestor analogous structures are basically the opposite of homologous structures these structures are anatomically different yet have a similar function let's take a look at two examples first the wing of an insect and the wing of a bird you can clearly see they are structurally very different however they are both used for flight another example is the leg of a horse and the leg of a grasshopper the grasshopper is an insect and has a segmented leg with an exoskeleton while the horse is a mammal with joints tendons and ligaments although the legs are structurally different they carry out a similar function analogous structures are not associated with common ancestors like the homologous structures are in addition analogous structures are associated with convergent evolution and homologous structures are associated with divergent [Music] evolution