All About Evolution
Evolution is the change over time. As organisms evolve, they go from simple to complex and develops things such as organ systems and legs. As time went on, new animals were created such as reptiles and mammals. More specifically, evolution is a change in allele frequency. There are four factors that drive a change in allele frequency, which helps adaptations, or alleles that help species survive.
One factor is called mutation. It is the only way new alleles are created and the alleles
made can either be helpful or harmful. The allele had to be heritable, or can be passed on. For example, if radiation affected a frog's skin color, its offspring would not be the changed color because the radiation did not affect its gametes, or sex cells. Gametes mist carry mutation for evolution. The mutation also may or may not affect reproductive success.
A second factor is genetic drift. This factor is a random change allele frequency. There are two examples of genetic drift. The first example is the founder effect, which is a random sample in a new place. An example of the founder effect is the Amish population, who have six fingers on their hands. The second example of genetic drift is population bottleneck, which is when a random sample of species survived from a disaster. An example of population bottleneck is cheetahs.
The third factor is migration. Migration is also known as gene flow. Migration is when a group of individuals move from one population to another. An example of migration is birds.
The fourth factor is natural selection, described by Charles Darwin. Natural selection is also known as survival of the fittest and is when those best suited to the environment survives and reproduces. An example of natural selection is when Darwin visited the Galapagos Islands and discovered different types of finch beaks.
made can either be helpful or harmful. The allele had to be heritable, or can be passed on. For example, if radiation affected a frog's skin color, its offspring would not be the changed color because the radiation did not affect its gametes, or sex cells. Gametes mist carry mutation for evolution. The mutation also may or may not affect reproductive success.
A second factor is genetic drift. This factor is a random change allele frequency. There are two examples of genetic drift. The first example is the founder effect, which is a random sample in a new place. An example of the founder effect is the Amish population, who have six fingers on their hands. The second example of genetic drift is population bottleneck, which is when a random sample of species survived from a disaster. An example of population bottleneck is cheetahs.
The third factor is migration. Migration is also known as gene flow. Migration is when a group of individuals move from one population to another. An example of migration is birds.
The fourth factor is natural selection, described by Charles Darwin. Natural selection is also known as survival of the fittest and is when those best suited to the environment survives and reproduces. An example of natural selection is when Darwin visited the Galapagos Islands and discovered different types of finch beaks.
Natural Selection
Natural Selection
There are three types of natural selection:
- The first type of natural selection is called Stabilizing Selection. In this type, the environment supports the medium. An example of this is a newborn baby. [1] If a newborn baby is too small when it is born, they are more likely to die within their first month as well as their early years of life. [2] If a baby is born too big, they might need help breathing and have abnormally thick heart muscles. [3]
- The third type of natural selection is called directional selection. In this type, the environment supports either extreme. An example of directional selection is tree height in forests. If tall trees are receiving more sunlight, they will grow taller and increase in number. However, if smaller trees cannot get sunlight because taller trees tower over them, the number of them will eventually decrease.
- The final type of natural selection is called disruptive selection. In this type, the environment supports both extremes. An example of this is moth colors. There are only black and white trees and three colors of moth: white, gray, and black. In areas where there are white trees, the white moths will survive because they are able to camouflage and the gray will be eaten because they will be easily seen. In black tree areas, the black moths will survive because they are able to blend in and the gray moths will die out because they stand out from the gray.
Disruptive Selection
Some Evidence of Evolution
Below are some (not all) pieces of evidence of evolution:
- One piece of evidence is the fossil record. This piece of evidence looks at the age of fossils either using relative dating (looking how far deep fossils are in the ground) or radiometric dating (fossil's exact age).
- Another piece of evidence is geography and species. This piece of evidence looks at how species are similar due to common ancestors and similar environments. For example, some fossils are found on South America and Africa because of a common ancestor that once lived on the super-continent, Pangaea.
- A final piece of evidence is embryology. This piece of evidence looks at the embryos of different species and how similar they are. This shows that species have a common ancestor if their embryos look similar to one another. For example, a fish, pig, and human embryo all have a tail and gills, showing we share a common ancestor.
Embryology
Evolution in Jellyfish
Special Adaptations Jellyfish Have:
- They are filter feeders in order to capture food like microscopic zooplankton. [4]
- They are made up of three layers, one of them being mesoglea. Mesoglea is a jelly-like substance and is made up of 95% water, allowing jellyfish to float. [5]
- They have nematocysts, or stinging cells, in order to protect the soft tissue of its body. [6]
- Their stinging cells also keep them warm in deeper, cooler water. [7]
Jellyfish also are the earliest known animals with organized tissue layers (epidermis and gastrodermis) and a nervous system. Jellyfish are also the earliest animals to evolve muscle-powered swimming instead of going along with the drift. Jellyfish are three times as old as the first dinosaurs, living since as long as maybe 700 million years ago. Finding jellyfish fossils are rare because they do not have any bones or hard parts of their bodies. However, in 2007, a group of scientists from the Smithsonian National Museum of Natural History discovered a fossils from 505 million years ago. [8]
Jellyfish Fossil Found by the Group of Smithsonian Scientists