explain the importance of homologous structures, analogous structures and vestigial structures in ............

Question

determining a possible evolutionary relationship between two types of organisms.

Answer 1

Homologous : Variations of the same structure that has enabled the organism to adapt to different environments. Eg.,
Arm of human, wing of bat, flipper of whale, foreleg of horse.
All anatomically similar; suggests a close evolutionary relationship.

Analogous: Structures having the same function, but suggest neither similarity in anatomy nor close relationship. Eg.,
wing of bird and wing of insect

Vestigial: Structure that currently has no function but may have been of use in the evolutionary past. Eg.,
appendix, coccyx (tail bone), extra toe on dogs, maybe
wisdom teeth.

Answer 2

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RE:
explain the importance of homologous structures, analogous structures and vestigial structures in ............
determining a possible evolutionary relationship between two types of organisms.

Answer 3

Crocodiles and horse are both tetrapods. Their legs are homologous structures because they are the same structures. The have the same bones inside. They inherited their legs from the same ancestor, which is a primitive reptile. Analogous structures are those that look and/or function similarly but are inherited from different ancestors. An example of an analogous structure is the legs of a crocodile and the legs of an insect. The common ancestor of birds and insects had no legs, and they evolved their legs independently of each other. The evidence for that is the fact that insect legs have no bones on the inside. Morphologically, crocodile legs and horse legs are quite different. For example, the horse has but a single toe, but crocodiles have five toes on each leg. Crocodiles walk on their palms, but horses walk on their toes. Therefore crocodile limbs and horse limbs have diverged morphologically from the condition in their common ancestor.

Answer 4

its shows
1. the origins of a structure and the closeness of species eg the arm bone in mammals (bats, whales, dongs, horses, humans) is all the same basic makeup, yet its very different in its look and use....all these species have a common ancestor that had the single upper bone (humerus), 2 lower bones (ulna and radius) and multiple phalanges.

2. analogus structures (like flying) have originated independently in different groups (eg insects, bats, pterodactlys and birds) by different means, but still have the same ability to fly....these are usually quite distantly related species.

3. Vestigial structures tell us about the past of a species and from this we can look at other species with similar OVERALL features like whales have vestigial legs, so we know they are mammals (eg have lungs, give birth to live young and feed them milk etc) based on other features, except they live in the sea and look like fish (which is analogous features again).
Snakes also have vestigial legs and we have an appendix, so we can see that the ancestors of snakes could walk, while our ancestors ate more vegetation....but we and snakes have changed our habitats, types of food we eat...but we know we are related to other aninmals that have appendix.

Answer 5

Well one thing I do know is that our appendix is a vestigial organ. It means it has no real known use, but that our ancestors probably had a use for it.