Animal And Plant Evolution Essay

An example of natural selection influencing evolution involves the African elephant. Because this species has ivory tusks that are highly valuable, hunters have radically altered the distribution of this species since 1930. Some African elephants, it turns out, do not develop any tusks, and in 1930, about 1 in 100 of them did not have any. The ivory hunters left these specimens alone because there was no ivory to harvest from the carcass. However, a lot of elephants who had tusks were killed by the thousands – without reproducing.
This means that, over time, the alleles that would tell the pachyderms to abstain from growing tusks moved along vigorously. As a result, even though a failure to grow tusks is a recessive trait, the percentage of some elephant populations without tusks has show up as high as 38 percent. You might think that this is a harmless change, but the problem is that elephants use their tusks to defend against natural predators (the kind that do not carry guns) and to dig in the dirt.
One lesson that we can take from this, is that it might only take what seems like an accident to us to bring radical change to the genetic trends within a species. It would be interesting to see how long it would take this trend to reverse itself – in other words, for the percentage with the tusks to grow back up to 99 percent – if people stopped hunting elephants for the ivory in their tusks. In a day and age when it is possible to make just about anything valuable synthetically, one hopes that nature will be able to go back soon.