The Toothpick Fish Lab simulated a real life situation that could have occurred in the environment. The main idea of this lab was to observe how some specific alleles disappear from species in order for the species to survive. This is called evolution, adaptation, or natural selection. The Toothpick Fish Lab made understanding this process easier by narrowing it down to one specific species: the toothpick fish.
Genotypes and Phenotypes
GG, Gr, Gy = Green
rr = Red
yy = Yellow
ry = Orange (incomplete dominance)
The Toothpick Fish Lab consisted of four generations of fish that evolved or adapted to their environment in order to survive. In the beginning, the first generation had four various scale colors: green, red, yellow, and orange. Since green was the dominant allele, most fish were green. However, three of the twelve fish were orange, one was red, and one was yellow. Six out of the seven green fish were heterozygous and one was homozygous dominant. Both, the yellow and red fish, were homozygous recessive. The orange fish, however, contained one red allele (r) and one yellow allele (y) and the alleles blended together because of the incomplete dominance. Next, the yellow fish were not able to camouflage in their green and red environment, so they became prey and all yellow fish died. Because of this, the second generation did not contain any yellow fish and only eleven offspring remained. The second generation offspring were mostly green and orange, though a couple of them were red. Six out of eleven were heterozygous and five out of eleven were either homozygous dominant or homozygous recessive. The second generation’s offspring however were more colorful than the second generation itself.
The third generation was a lot like the first generation. It had fish of all colors; even yellow. The proof is the following. If two fish were to have an offspring it could be yellow. There is 25% chance that the offspring will be yellow, so five fish were green, two were red, one was yellow, and three were orange. With that being said, the fourth generation was sort of like the second generation. It contained eight green fish. Also, the population decreased by one fish because a yellow fish from the previous generation was eliminated once again because of its inability to camouflage. However, from the fourth generation only three fish survived in the end because of the chemical dumping in the river by a nearby factory.
A factory by the river dumped harmful chemicals into the river killing all the algae and seaweed that provided protection to all the green fish. All the green fish died because they were exposed to their predators and had nowhere to hide. Also, because green is the dominant allele, it showed up in most of the fish in the fourth generation causing the green allele to go extinct. This is just one example of what occurs in the wild almost every day.
Instead of a chemical dumping, an excessive amount of fishermen could show up after the second generation to fish for orange fish only. This event would cause a major decrease in the orange fish population. All the orange fish would be caught by the fishermen and sold at the supermarket. Therefore, the population of orange fish would decrease alarmingly. Also, this would affect the coming generations. For example, generation three would have only seven fish in total and there would be no more orange fish. If the fishermen keep coming back to fish for the orange fish, then the orange fish could go extinct in the fourth generation.
As shown by this lab, species have evolved and adapted to their environment in the past, are evolving right now, and will continue to evolve as the need arises in the future. This process is called natural selection. As seen from the toothpick fish, populations have changed based on their needs to survive in the environment. The population sizes have also changed based on the ecological disasters that occurred in the area. The Toothpick Fish Lab was extremely beneficial because it displaying how animals react to the environmental changes, natural or human caused.
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