Individual Assignment
• Each student is required to submit an individual assignment.
• Imagine the future evolution of an organism (an existing species) and
describe its adaptative features for a particular habitat that it lives in.
• Make a sketch of this organism.
• Annotate 3 adaptive features on the sketch, write a 100-150 words
description for each adaptive feature.
• Include reference if applicable.
Evolutionary adaptations (@ 100-150 words):
1. Eyespots
The eyespots at the rump of plains zebras is an anti-predator adaptation. Plains zebras are preyed by ambush predators such as lions, the eye- like pattern at the rump helps to deter predators and increase their survival rate (Radford et al., 2020). Plains zebras (and other zebra species) are born with black and white stripes, and the pattern of the stripes varies among individuals. Individuals with stripe pattern that slightly resembles a circular pattern have slight fitness advantage over individuals that do not; and pattern that resembles eyes are more advantageous than pattern that just resembles a cycle. Therefore, the eye-like stripe pattern is favoured by natural selection because those zebras have higher survival rate, hence are more likely to pass on their gene to the next generation.
2. Black and white neck mane
They evolve a thick layer of mane with black and white bands around the neck. The mane provide production to the throat when a predator attack, therefore is favoured by natural selection. The conspicuous black and white pattern on the mane is the evolutionary outcome of sexual selection. Males with more conspicuous black and white stripes on the neck mane stand out more to the predators, therefore have a higher risk of predation. Females use the black and white pattern as an indicator of the males’ fitness (the ability to escape from predators) and prefer to mate with males that have more conspicuous stripe pattern.
3. Widened snout
The snout of plains zebras is flat and widened. This gives them an advantage when grazing by allowing them bite off more grass. Individuals that have a wider snout are able to graze more efficiently than individuals that have a narrower snout, therefore, get an advantage in the intra- specific competition for food. When grazing, plains zebras grab a mouthful of grass, then put their head up to stay vigilant of predators while chewing (Sze et al., 2021). A wider snout allows them to grab more grass every time they put their head down and spend more time looking out for predators, reducing the risk of predation.
References:
Radford, C., McNutt, J.W., Rogers, T., Maslen, B., & Jordan, N. (2020) Artificial eyespots on cattle reduce predation by large carnivores. Communications
Biology, 3:430.
Yiu, S.W., Keith, M., Karczmarski, L., & Parrini, F. (2021) Predation risk effects on intense and routine vigilance of Burchell's zebra and blue wildebeest.
Animal Behaviour, 173:159-168.