Question

Elephant Tusklessness
Sclentists working in Gorongosa National Park are trying to determine the genes responsible for tusk development in elephants. Normally, more than 90% of female African elephants have tusks. But in Gorongosa National Park, which has a history of heavy poaching, about 50% of the elephants are tuskless. To study this striking phenomenon, scientists are searching for the gene or genes responsible for tusk development and how variations in these genes can lead to tusklessness.
During the Mozambican Civil War (1977-1992), elephants were heavily hunted for ivory. After the war, researchers documented a significant increase in tuskless female elephants in Gorongosa National Park. Figure 1 shows the percentage of tuskless females pre- and post-war. This change illustrates how human actions can alter evolutionary pressures.

Using evidence from the tuskless elephant case, explain how natural selection operates on heritable varlation to drive adaptation of populations. In your response, Include:
1. The role of human-induced selective pressure
2. Why tusklessness increased over time
3. How does this exemplify the four factors of evolution?

Write in a 5th graders response In one sentence each but provide one evidence for each question From above

Answer 1

1) Role of human-induced selective pressure: Humans hunting elephants for ivory made tusked elephants more likely to be killed, so tuskless elephants had a better chance to survive.
Evidence: Before the war most female African elephants had tusks, but after heavy poaching in Gorongosa about half the females were tuskless, showing hunting changed which elephants survived.

2) Why tusklessness increased over time: Because tuskless elephants survived the hunting more often and had more calves, the tuskless trait became more common in later generations.
Evidence: Park records and studies show the percent of tuskless females in Gorongosa rose to about 50% after the war, meaning tuskless elephants reproduced more successfully.

3) How this exemplifies the four factors of evolution: The case shows variation (some elephants had tusks, some did not), heritability (tusklessness is passed to offspring), differential survival/reproduction (tuskless lived and reproduced more), and a change in the population’s genes over time (tuskless became more common).
Evidence: Figure 1 and field data from Gorongosa document the rise in tuskless females after heavy poaching, which fits all four factors.