This means that closely related species often do share homologous traits which are often of similar structure but may have the same or different function.
Organisms that share a common ancestor often form what is called a monophyletic group when classified based on phylogenetic relationships.
Often this close relationship is seen in the fact that patterns of development during embryology are very similar among the organisms with homologous structures. For example, the embryo forms of all types of vertebrate animals look very similar in appearance. There are many examples of animals that have homologous structures. One classic example is the limbs of vertebrates, in which there is a basic pattern that is the same among all representatives, but that has become modified and adapted for different functions.
The same bones, namely the humerus, radius, and ulna, can be seen in the arms of a bat, a bird, and a human, for example, even though a bat and a bird have wings while a human does not. Thus, the bones are modified for flight in some vertebrate animals, while in others they are used for walking and running. The leaves of some types of plants are examples of homologous structures.
In some of the plants, the leaves arose from the same basic pattern and ancestor, but while some were modified to store water e. Venus fly trap and pitcher plant. Analogous structures evolved independently to have the same or similar function, and thus may appear on the surface to have a similar structure, but often this is very different from one organism to another.
Organisms which have analogous structures are not usually closely related and do not therefore share a common ancestor, and so a phylogenetic tree would not be monophyletic. Instead each analogous structure evolved separately in each organism to serve the same or similar purpose. Although the structures are not homologous, they often adapt organisms for the same role, e. Analogous structures can result from convergent evolution, for example the streamlined body shape of squid and fish both enable ease of swimming.
Convergent evolution can often be seen when organisms in completely different parts of the world show the same morphological adaptations to environmental conditions. Analogous structures that are evident in the animal kingdom include the wings of birds and the wings of insects. The bird wings consist of hollow bones that evolved from primitive chordate animals. The insect wings evolved separately from the gill structures of primitive aquatic insects. African euphorbias have succulent leaves for water storage, similar to those of cacti found in the New World.
However the modified storage leaves of these plants represent convergent evolution, having arisen separately from different ancestral plants.
Thus, although the leaves have the same function in euphorbias and cacti, they have different ancestral origins. Homologous structures are structures that evolve in living organisms that have a common ancestor. Analogous structures are those that evolve independently in different living organisms but have a similar or the same function.
Organisms which have homologous structures are always closely related and share a common ancestral form. Organisms which have analogous structures are not closely related and do not arise from the same ancestor. Make sure you get the inside information on the test before you make your decision.
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It is inherited from a common ancestor. It is not inherited from ancestors. It develops in related species. It develops in unrelated species. It is a result of divergent evolution.
It is a result of convergent evolution. It is developed as a result of the adaptation to a different environment. It is developed as a result of the adaptation to a similar environment. Some of the examples of Homologous Structures are the four limbs of tetrapods. Mice, crocodiles, birds and other animals and birds with four limbs form perfect examples of Homologous structures.
As the ancestors of these tetrapods evolved in the universe with four limbs, so as their descendants have inherited the same feature. However, not all characters can be called homologies.
For example, birds and bats both have wings and if compared to mice and crocodiles, they do not have. Does that anyway mean that birds and bats are more closely related to one another than to mice and crocodiles?
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