Evolution of Giraffes for Survival

“Each species has a different colorations and the color dots represent their home territories. Their colorations help them blend into the part of Africa that they live in.”

— Nisha

AISM Science Magazine | 95

Evolution of Giraffes for Survival

_____Nisha_____

The Giraffe is the tallest living terrestrial animal. Males can exceed 5.5 feet, and females are around 4.5 feet. They live on a diet of Acacia trees, they are 40 feet or 3 meter long trees. It is an animal that is native the continent of Africa. Although giraffes were once spread around the world, 20 to 25 million years ago, the giraffe's ancestors also roamed around Europe and Asia. (Herbison and Frame 1) While Giraffes are only native to Africa, they have subspecies that live in different parts. Each species has different colorations and the color dots represent their home territories. Their colorations help them blend into the part of Africa that they live in. There are not many fossils of them out of Africa, but there is enough information for scientists to come up with evolution theories. (Giraffe Worlds) There are two theories, the one that the world accepts today is the Darwinian theory, the one that is not valid and not accepted anymore is the Lamarck theory. .

The earliest giraffe dates back to around 25 million years ago, using fossil evidence, scientists believe that giraffes had long legs, short necks, and ossicones that pointed upward. The picture on the left is what scientists imagined giraffes ancestors looked like. The Darwinian theory is a theory created by Charles Darwin in 1859. His theory suggested that the fittest will survive. He believed that giraffes had a genetic mutation that allowed them to grow longer necks. These animals were able to eat more and so they were stronger. That meant that the stronger males would be the ones breeding more, and their genetic code would get passed down to the next generations. The animals that could not get enough to eat, were not strong enough to mate with the females, and then they would die without having offspring. (Khan Academy) There is also another theory that suggests something different. The Lamarck theory was created by Jean-Babtiste Lamarck in the early 1800’s. Food on the ground was scarce, and most of the food was on the trees. He believed that animals were constantly raising their neck to be able to reach the trees for food. He thought that overtime the size of their necks would be longer that would provide them an adaptation that allowed their survival. Although, this theory is not supported anymore, after the Darwinian theory was created, the Lamarck theory was not widely accepted anymore. Scientists suggest that the Darwinian theory makes more sense, is more valid, and that is the main theory that is accepted worldwide. (Giraffe Worlds)

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_____Nisha_____

The image on the right is fossil evidence of the evolution of giraffes. Archeologists believed that the giraffe's ancestors were the Okapia Johnstoni. They found that the Okapia had a short neck that was 1.9 feet. They believed that the Okapia Johnstoni species evolved into the Samotherium Major. The Samotherium Major had a neck that was 3.2 feet. These days giraffes have a neck that is 5.5 feet. The giraffe evolved a lot in order to become more habitable to their environment. (Geggel 2)

Citations:

Websites

- Geggel, Laura. “7-Million-Year-Old Fossils Show How the Giraffe Got Its Long Neck.” LiveScience​, Purch, 25 Nov. 2015, www.livescience.com/52903-transitional-giraffe-fossils.html​.

- Lory Herbison & George W. Frame. “Giraffe.” ​Encyclopædia Britannica​, Encyclopædia Britannica, Inc., 12 May 2020, ​www.britannica.com/animal/giraffe​.

- “Giraffe Evolution.” ​Giraffe Facts and Information​, www.giraffeworlds.com/giraffe-evolution/​.

- “Darwin, Evolution, & Natural Selection (Article).” ​Khan Academy​, Khan Academy, www.khanacademy.org/science/biology/her/evolution-and-natural-selection/a/darwin-evo lution-natural-selection​.

Images

- Geggel, Laura. “7-Million-Year-Old Fossils Show How the Giraffe Got Its Long Neck.” LiveScience​, Purch, 25 Nov. 2015, www.livescience.com/52903-transitional-giraffe-fossils.html​.

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- Briggs, Helen. “Scientists Weigh in on 'Giraffe Relative' Fossil.” ​BBC News​, BBC, 13 Jan. 2016, ​www.bbc.com/news/science-environment-35292660​.

- Gruber, Karl. “New Scientist.” ​New Scientist​, 17 Sept. 2015, www.newscientist.com/article/2058123-giraffes-spend-their-evenings-humming-to-eachother/​.

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