Examples of vestigial structure in the following topics:
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- Vestigial structures have no function but may still be inherited to maintain fitness.
- These unused structures without function are called vestigial structures.
- Vestigial structures are often homologous to structures that function normally in other species.
- The vestigial versions of a structure can be compared to the original version of the structure in other species in order to determine the homology of the structure.
- Discuss the connection between evolution and the existence of vestigial structures
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- Scientists call these synonymous parts homologous structures.
- Some structures exist in organisms that have no apparent function at all, appearing to be residual parts from a common ancestor.
- These unused structures (such as wings on flightless birds, leaves on some cacti, and hind leg bones in whales) are vestigial.
- Great ape embryos, including humans, have a tail structure during their development that is lost by birth.
- Like anatomical structures, the structures of the molecules of life reflect descent with modification.
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- Amphibians evolved from fish 400 million years ago and are characterized by four limbs, moist skin, and sensitive inner ear structures.
- Some species of salamanders and all caecilians are functionally limbless; their limbs are vestigial.
- Additional characteristics of amphibians include pedicellate teeth (teeth in which the root and crown are calcified, separated by a zone of noncalcified tissue) and a papilla amphibiorum and papilla basilaris (structures of the inner ear that are sensitive to frequencies below and above 10,00 hertz, respectively).
- However, it also had four limbs, with the skeletal structure of limbs found in present-day tetrapods, including amphibians.
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- The chordates are named for the notochord: a flexible, rod-shaped structure that is found in the embryonic stage of all chordates and also in the adult stage of some chordate species.
- In humans and other apes, the post-anal tail is present during embryonic development, but is vestigial as an adult.
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- The only male amphibians that possess copulatory structures are the caecilians, so fertilization among salamanders typically involves an elaborate and often prolonged courtship.
- They have vestigial limbs which is evidence that they evolved from a legged ancestor.
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- Cyanobacteria are a group of photosynthetic bacteria with all the conventional structures of prokaryotes.
- The green algal endosymbiont also exhibits a stunted vestigial nucleus.
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- Limbless reptiles (snakes and other squamates) have vestigial limbs and, as with caecilians, are classified as tetrapods because they are descended from four-limbed ancestors.
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- Protein structures are very complex, and researchers have only very recently been able to easily and quickly determine the structure of complete proteins down to the atomic level.
- Early structural biochemists conceptually divided protein structures into four "levels" to make it easier to get a handle on the complexity of the overall structures.
- But, because the final protein structure ultimately depends on this sequence, this was called the primary structure of the polypeptide chain.
- The most common forms of secondary structure are the α-helix and β-pleated sheet structures and they play an important structural role in most globular and fibrous proteins.
- The tertiary structure of a polypeptide chain is its overall three-dimensional shape, once all the secondary structure elements have folded together among each other.
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- Homology is the relationship between structures or DNA derived from the most recent common ancestor.
- Although these two structures do not look similar or have the same function, genetically, they come from the same structure of the last common ancestor.
- If we go all the way back to the beginning of life, all structures are homologous!
- As a result, hybrid or mosaic structures can evolve that exhibit partial homologies.
- The opposite of homologous structures are analogous structures, which are physically similar structures between two taxa that evolved separately (rather than being present in the last common ancestor).
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- Most leaves have similar essential structures, but differ in venation patterns and leaf arrangement (or phyllotaxy).
- A leaf may seem simple in appearance, but it is a highly-efficient structure.
- Petioles, stipules, veins, and a midrib are all essential structures of a leaf.