EVOLUTION
Evolution is the idea of change over time. Organisms all over the world have changed over time, and have ranged from simple to complex in their changes, though these organisms are still changing and will continue to do so. However, evolution truly springs from changes that occur in allele frequency, which affects an organism's traits. It can result in complete changes or in different types of similar traits. These traits that organisms evolve are called adaptations, and come from alleles that will help an organism survive in their environments. Allele frequencies can change when driven by factors, such as mutation, genetic drift, migration, and natural selection. With mutation, new alleles can be created, but can either be harmful or helpful to an organism. For the allele to be passed on as a mutation, the gametes of the organism have to be affected in order to carry along the mutation through reproduction. Genetic drift involves a random change in allele frequency. Examples of this are the founder effect, which is a random sample going to a new place, or population bottleneck, which is when many organisms of a species are affected negatively with a few lucky ones who do not receive this effect. In migration, the allele frequencies change with gene flow, or when a group of individuals moves from one population to another and is affected by the new environment around them, causing them to change.
The last of these factors is natural selection, which is Darwin's theory of "survival of the fittest," where those best suited to an environment survives and is able to reproduce to carry on their genes. In natural selection, adapted advantages give a species bigger and better reproductive success, passing on the mutation that they carry [1]. Darwin's idea of natural selection disproved the previous beliefs that Earth was 6000 years old and that all organisms were created then and have stayed unchanged since. For natural selection to occur, there must be variation in a trait, the trait must be heritable, and there must be differential reproductive success. Natural selection also has 3 different kinds. There is stabilizing selection, where an environment supports the medium point between extremes, directional selection, where an environment supports either one of the extremes, or disruptive selection, where an environment supports both extremes.
Evolution can often be identified with evidence, including fossils, geography, comparative anatomy, and molecular biology. Age of fossils is a form of evidence which uses radiometric dating to determine when specific fossils are from, to define the relative dates of when certain organisms had different, evolved features. With geography, there are the same fossils found on different continents across the ocean from each other to depict where similar species originated and how they spread due to common ancestors and the similar environments. Comparative anatomy helps to show evidence of evolution because of the different homologous structures, vestigial organs (structures that no longer serve a purpose such as a human appendix), divergent evolution (adaptations of similar species to different environments such as Darwin's finches), convergent evolution (unrelated species show similar characteristics due to their environment), and embryology (to show similarities and differences between embryos to depict common ancestors). Molecular biology shows that in DNA, whoever is more genetically similar is more closely related in the history of evolution in organisms.
The last of these factors is natural selection, which is Darwin's theory of "survival of the fittest," where those best suited to an environment survives and is able to reproduce to carry on their genes. In natural selection, adapted advantages give a species bigger and better reproductive success, passing on the mutation that they carry [1]. Darwin's idea of natural selection disproved the previous beliefs that Earth was 6000 years old and that all organisms were created then and have stayed unchanged since. For natural selection to occur, there must be variation in a trait, the trait must be heritable, and there must be differential reproductive success. Natural selection also has 3 different kinds. There is stabilizing selection, where an environment supports the medium point between extremes, directional selection, where an environment supports either one of the extremes, or disruptive selection, where an environment supports both extremes.
Evolution can often be identified with evidence, including fossils, geography, comparative anatomy, and molecular biology. Age of fossils is a form of evidence which uses radiometric dating to determine when specific fossils are from, to define the relative dates of when certain organisms had different, evolved features. With geography, there are the same fossils found on different continents across the ocean from each other to depict where similar species originated and how they spread due to common ancestors and the similar environments. Comparative anatomy helps to show evidence of evolution because of the different homologous structures, vestigial organs (structures that no longer serve a purpose such as a human appendix), divergent evolution (adaptations of similar species to different environments such as Darwin's finches), convergent evolution (unrelated species show similar characteristics due to their environment), and embryology (to show similarities and differences between embryos to depict common ancestors). Molecular biology shows that in DNA, whoever is more genetically similar is more closely related in the history of evolution in organisms.
Evolution in Green Darners
SPECIAL ADAPTATIONS
-Green Darners have a small water chamber in their anus that can shoot water out of them to propel forward, and away from potential predators. They pump water over gills located in their rectal chamber [2]
-Active thermoregulators: "By contracting and vibrating their wing muscles, these dragonflies can warm their bodies; they can also modulate the flow of hemolymph throughout the body to transfer heat." [3]
-They have a labium, which is the bottom jaw in their mouth that unhooks for them to be able to catch prey and pull it into their mouths so they can chew.
-They can fly forwards and backwards, and have a fast darting skill to escape predators.
-Green Darners have sharp vision which is developed for seeking to catch prey and watching to avoid predators
-Their legs act as a nets to help them catch prey while flying, then they can use their shorter legs to eat while on the go. [4]
In terms of evolution in green darners, there are around 4,500 species of dragonfly in the world. "Fossil evidence has shown they're amongst the oldest insects on Earth, and existed more than 300 million years ago." [4] Their abdominal appendages have evolved a few times to adjust to living needs. Also, some males have few vestigial appendages on their bodies from previous use. Modifications on almost all body parts of the dragonfly have been made to evolve the dragonfly to adjust to their environments. Many different types of dragonflies have evolved to keep up with their environments and survive through the struggles of living in different environments.
-Green Darners have a small water chamber in their anus that can shoot water out of them to propel forward, and away from potential predators. They pump water over gills located in their rectal chamber [2]
-Active thermoregulators: "By contracting and vibrating their wing muscles, these dragonflies can warm their bodies; they can also modulate the flow of hemolymph throughout the body to transfer heat." [3]
-They have a labium, which is the bottom jaw in their mouth that unhooks for them to be able to catch prey and pull it into their mouths so they can chew.
-They can fly forwards and backwards, and have a fast darting skill to escape predators.
-Green Darners have sharp vision which is developed for seeking to catch prey and watching to avoid predators
-Their legs act as a nets to help them catch prey while flying, then they can use their shorter legs to eat while on the go. [4]
In terms of evolution in green darners, there are around 4,500 species of dragonfly in the world. "Fossil evidence has shown they're amongst the oldest insects on Earth, and existed more than 300 million years ago." [4] Their abdominal appendages have evolved a few times to adjust to living needs. Also, some males have few vestigial appendages on their bodies from previous use. Modifications on almost all body parts of the dragonfly have been made to evolve the dragonfly to adjust to their environments. Many different types of dragonflies have evolved to keep up with their environments and survive through the struggles of living in different environments.