How did giraffes get their long necks?
Yes, giraffes may have evolved to be able to reach food at higher elevations, but their long necks may also be the result of fierce competition for mates, according to new research published this week in Science by an international team of paleontologists and paleobiologists.
What factors might have contributed to the evolution of the long neck giraffes?
The accepted theory on giraffe evolution is that the giraffes with the longest necks passed on their genes through natural selection, and that it took millions of years to get the animal we see now. The two forces that drove giraffes towards elongating their necks are simple. The need to eat and the need to breed.
Do fish have a laryngeal nerve?
The recurrent laryngeal nerve connects the brain and the larynx. The nerve’s route was relatively direct in our fish-like ancestors, but in vertebrates the nerve loops down from the head, around the aorta, and back up to the larynx.
Do giraffes have a recurrent laryngeal nerve?
The recurrent laryngeal nerve is an often cited example of “unintelligent design” in biology, especially in the giraffe. The nerve appears early in embryonic development, before the pharyngeal and aortic arches are separated by the development of the neck.
How would Darwin explain giraffes with long necks?
A Darwinian theory of evolution posits that it was through random variation that some giraffes had longer necks than others. Thanks to their long necks, they were able to reach leaves high up in the trees in their environment.
How would Charles Darwin explain why giraffes have long necks?
What feature of the environment enabled the development of long neck of the giraffe according to Lamarck’s theory?
According to Lamarck, the giraffe got its long neck because its ancestors stretched theirs to eat leaves that were just out of reach. This stretching of the neck was passed on to their offspring, over generations, until it reached its current length.
Why is the laryngeal nerve so long?
Evidence of evolution Over the course of evolution, as the neck extended and the heart became lower in the body, the laryngeal nerve was caught on the wrong side of the heart. Natural selection gradually lengthened the nerve by tiny increments to accommodate, resulting in the circuitous route now observed.
Why is the laryngeal nerve 15 feet long in a giraffe?
The laryngeal nerve is 15 feet long in giraffes because? the nerve is modified from an ancestor that did not have a neck.
Which recurrent laryngeal nerve is longer?
left recurrent laryngeal nerve
The left recurrent laryngeal nerve curves medially around the aortic arch during development and is approximately 1 m long. In contrast, the right recurrent laryngeal nerve courses around the right subclavian artery and is approximately 25% shorter.
Do giraffes have two brains?
The three brains of the adult male giraffes weighted respectively 722.7, 766.1 and 770.4 g, with a mean of 753.1 ± 15.23 g (Table 1). The body weights were similar with an average weight of 703.3 ± 50.4 kg. The EQ calculated with these means resulted in a value of 0.76 (Table 3).
What do you observe in Darwin’s theory of evolution of giraffes?
What feature of the environment enabled the development of the long neck of giraffe according to Lamarck’s theory?
How does the neck of giraffe supported the theory of use and disuse?
The classic example used to explain the concept of use and disuse is the elongated neck of the giraffe. According to Lamarck’s theory, a given giraffe could, over a lifetime of straining to reach high branches, develop an elongated neck.
Which of the following ideas explains the transmission of long neck trait for giraffe according to Lamarck?
In the case of a giraffe, Lamarck believed that giraffes once had short necks that got progressively longer as members of each subsequent generation stretched their necks as long as they could. In doing so, Lamarck believed that each generation would grow slightly longer necks and pass that trait onto their offspring.
Where is the vasovagal nerve?
The right vagus nerve travels down the right side of your body. “Vagus” is the Latin word for wandering. Your vagal nerves take a long, winding course through your body. They exit from your medulla oblongata in your lower brainstem.