***why do embryos develop ancestral structures if they are only going to discard
ID: 148865 • Letter: #
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***why do embryos develop ancestral structures if they are only going to discard them later? / why do embryos develop and discard organs? ***give examples of vertebrates that are not vertebrates *** ***why do embryos develop ancestral structures if they are only going to discard them later? / why do embryos develop and discard organs? ***give examples of vertebrates that are not vertebrates *** ***why do embryos develop ancestral structures if they are only going to discard them later? / why do embryos develop and discard organs? ***give examples of vertebrates that are not vertebrates ***Explanation / Answer
Organs that do not have a function in the body are called Vestigial organs. They still continue to form in a modern organism because their elimination or presence can be altered by genetic changes (Natural selection). They may have developed a minor function or may be of some advantage to the organism. If not, they may not have any disadvantage.
Since all modern organisms have them, there is no competition against them and they are not obliterated from the species as a whole.
Vertebrates come under the category of Chordates.
Chordates are all organisms that have a notochord (homologous to the spinal cord of humans). Vertebrates are the chordates that have bones around this cord (backbone). Invertebrates do not have a backbone.
However, there are some chordates called Cephalochordates in who the notochord persists throughout the life i.e., it is not replaced by a vertebral column. Branchiostoma and Epigonichthys are two examples of cephalochordate animals. (marine)
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