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An ancestor of the elephant, Phiomia, had a long nose-like structure called a proboscis which evolved into the trunk of the elephant - NSC Life Sciences - Question 4 - 2016 - Paper 2
Question 4
An ancestor of the elephant, Phiomia, had a long nose-like structure called a proboscis which evolved into the trunk of the elephant. The proboscis was used to gathe... show full transcript
Worked Solution & Example Answer:An ancestor of the elephant, Phiomia, had a long nose-like structure called a proboscis which evolved into the trunk of the elephant - NSC Life Sciences - Question 4 - 2016 - Paper 2
Step 1
Lamarckism
Answer
Lamarck's theory suggests that the ancestral elephant stretched its proboscis to reach leaves higher in trees or further from its body. This behavior led to the following conclusions:
- The more it used its proboscis, the longer it became.
- The offspring inherited the acquired traits, including a longer proboscis.
- Over many generations, the length of the proboscis increased until it evolved into the trunk we see in modern elephants.
Step 2
Darwinism
Answer
Darwin's theory introduces the concept of natural selection, highlighting that:
- There is a great deal of genetic variation among the offspring of the ancestors.
- Some individuals had long proboscises while others had short ones.
- Changes in environmental conditions or competition among animals for food led to those individuals with longer proboscises having an advantage.
- The animals with shorter proboscises were less likely to survive.
- Those individuals with the longer proboscises reproduced and passed this trait to their offspring, resulting in future generations having a greater proportion of animals with longer proboscises.
Step 3
Artificial selection
Answer
In artificial selection, humans can influence the traits in elephant populations by selecting for desirable characteristics such as length of trunk. This can be accomplished by:
- Selecting elephants with long trunks to breed.
- Encouraging those that are purebred for long trunks to reproduce.
- Continuing to select offspring that exhibit further increases in trunk length, thereby enhancing this trait in future generations.