Evolution can occur and change the phenotypes and genotypes of species greatly.
Gila monsters have evolved to become animals that are capable of surviving harsh, dry environments, with a shortages of freshwater and limited vegetation, due to the 95% of their life spent underground. Gilas have become slow, venomous nest hunters, that do not need speed. Gila monsters are about to undergo a predicted gradualism, over 10,000,000 years based on the Hardy-Weinberg principle, that includes things such as mutations and natural selection. 10,000 years The Gila monster feeds on small animals, such as frogs, and eggs of other animals, especially birds. Gila monsters spend more than 95% of their lifetime underground in their burrows. This comes out to about 90% of their day in their burrows.
Gilas only eat 3 to 4 times a year, and can go months at a time without eating. They store fat in their tails, so the bigger the tail, the better off they are to survive, especially during the winter. Gilas with smaller, shorter tails may go extinct, because they will have to eat more and emerge out of their burrows more, risking being eaten by predators, such as coyotes. Natural selection will help in this, because the Gilas with the larger, fatter tails store more fat, and therefore have higher fitness. Gila monsters use their claws to dig burrows to live in, as well as digging for eggs. Gila monsters have evolved to have sharper claws. This will benefit them in the way that they will find prey buried deeper easier as well as a place to live.
Gila monsters need their sharp claws to dig burrows for themselves, because the temperature on the island will increase throughout the years. This is an example of directional selection, because the extreme of longer, sharper claws is favored over shorter and normal claws. Dorsal scales on the Gila monster are an example of stabilizing selection, because the dorsal scales act as an “armor” to the Gilas. All of the Gilas have dorsal scales, because without them, they would be more vulnerable to predators.
However, with too many dorsal scales overlapping each other, they would be less flexible. The Gilas are similar to their “cousin”, the beaded lizard, in the way that they both have dorsal scales. This is an example of a homologous structure. Gilas and beaded lizards shared a common ancestor, however speciation occured, due to barriers such as estuaries, or geographic isolation, due to different mating times, or temporal isolation, and due to differences in behavior, or behavioral isolation.
Coevolution exists between Gilas and beaded lizards today. 100,000 years Gila monsters need their double grooved sharp teeth to grind venom into other animals, and even sometimes humans. These teeth latch on to the victim and inject venom into the victim. This means that Gila monster teeth need to be very sharp.
Teeth are also used during mating. Males wrestle with each other for up to around 12 hours, and use their teeth and venom to fight the other male. Though the venom is harmless to other Gilas, sharper teeth may be a benefit for biting the other monster. So, at 100,000 years, evolution has occurred, and natural selection has taken place, making those Gilas with sharper teeth surviving better, and having higher fitness. 1,000,000 yearsIn 1,000,000 years, Island C will suffer an even greater shortage of water.
In order to survive, the Gila monster will have to spend an even greater amount of time underground. With this, they willhave an even larger, fatter tail, to be able to store more fat from its meals. A larger body will help with reproduction. Males wrestle each other to fight for a female. The male with a larger body will win and end up on top and end up with the female.
Natural selection will allow this to occur.Due to harsher conditions, Gilas will have to find their prey better. They will develop a longer tongue to pick up scent particles better.
The Gila Monster flicks its forked tongue to pick up scent particles that can lead the animal to food, including eggs, baby birds and small mammals. The forked tongue in Gila monsters is an example of a single-gene trait, you either have it or you do not. However, without this forked tongue, it may be harder to find prey and watch for predators, resulting in extinction. This is another example of directional selection, where longer tongues are favored. These Gila monsters have met genetic equilibrium, and the allele frequencies of the population are all the same. 10,000,000 yearsGila monsters use their venom to paralyze prey and fight off predators.
A mutation can make this venom stronger, making those Gilas with stronger venom to paralyze even predators, will result in a higher fitness of those Gilas. In an environment with higher temperatures and shortages of water, the environment will change. Some areas may have lighter rocks, and some areas may have darker rocks. The Gila monster will change coat color by mutations, and become lighter in the lighter areas, and darker in the darker rocked areas. However, these are determined by polygenic traits. The Gila monster will match the color of the area for better camouflage. This is an example of disruptive selection. Both lighter coat colors and darker coat colors are favored.
Gilas migrating to another area with lighter rocks will create a founder effect, and genetic drift will occur. The migratory population of Gilas may also go through adaptive radiation, and eventually, due to geographic isolation, behavioral isolation, and temporal isolation, speciation would occur yet again. This would result in the inability of these organisms to interbreed and produce viable offspring.