One day soon, this line of thought will look every bit as stupid as when Freudian theories were advanced to explain absolutely every facet of human behavior. The long neck of giraffe is an adaptation, this helps the giraffe to survive for millions of years. Scientists have sequenced the genome of the giraffe for the first time, uncovering DNA quirks that help explain how the tallest animals on earth developed their remarkably long necks. Sign up to read our regular email newsletters. The evidence supporting the high-feeding theory is surprisingly weak. Giraffes with longer necks could reach long heights and had better nutrition than the Giraffes with shorter ones. Besides just fighting and eating, a giraffe's long neck gets it a better view to look for predators, water, and food. They use there long necks to fight, to see who get to get the female giraffe A study last year by Graham Mitchell of the University of Pretoria in South Africa and colleagues apparently delivered a knock-down blow to the “necks for sex” theory. Darwin proposed that these traits developed by a random chance. How the giraffe got its long neck The giraffe’s journey to long-necked wonder began more than 20 million years ago, a new study finds. The two forces that drove giraffes towards elongating their necks are … We cannot know why the giraffe's neck evolved to be longer and longer, because we can't tell what came first: lengthening of the neck, or lengthening of the legs. So the big question now is “How did Giraffes evolve to have a long neck?”. One of the first evolutionary thinkers, Jean-Baptist Lamarck, offered a short description of how the giraffe evolved in his major work, Philosophie Zoologique, which was published in 1809: It is interesting to observe the result of habit in the peculiar shape Sexual selection often drives males to develop spectacular attributes – think peacocks’ tails or the feathers of birds of paradise – to impress females, but the females remain relatively dowdy. Among these theories are the Lamarck theory and Darwin’s theory (Hodge, 2008). This idea has been around since 1809, when French naturalist Jean Baptiste Lamarck suggested that the giraffe's long neck evolved from its continual striving to reach food. appear to have misinterpreted this result”. The latest and rather surprising theory, which hasn’t been proposed before, is that the giraffe’s long necks are the result of sexual selection—to compete for females, male giraffes developed a long neck. Related: Mysterious deaths of the Amish community, The Lamarckian theory states that a change in an organism can pass to the offspring. Giraffes’ necks are long, but there have been longer ones. Using concept of natural selection, explain howthe giraffe most likely came to have such a long neck. There are two theories: one from Jean-Baptiste Lamarck and the other from Charles Darwin. is a phenomenon in which the DNA is changed in such a way that the genetic message carried by that gene is altered. These are the different reasons for our question “How did Giraffes evolve” Giraffes also have the same number of vertebrates as that of human i.e. The second part of Lamarck’s evolution involved the inheritance of acquired traits. How is natural selection in the evolution of long necks in giraffes best explained? Zoologger is our weekly column highlighting extraordinary animals – and occasionally other organisms – from around the world. Read previous Zoologger columns: The toughest fish on Earth… and in space, Vultures use twigs to gather wool for nests, The biggest living thing with teeth, Globetrotters of the animal kingdom, Judge Dredd worm traps prey with riot foam, Flashmobbing locusts have redesigned brains, Smart camo lets glow-in-the-dark shark hide, Attack of the self-sacrificing child clones, The most kick-ass fish in the sea, The most bizarre life story on Earth?, Keep freeloaders happy with rotting corpses. A Giraffe that lengthened its neck with its struggle passed it to its offspring rather than the original short neck. Long necks come at a cost. Two forces that drove Giraffe to lengthen their neck is simple – the need to eat and the need to breed. That does not mean that, at some point, those answers will not become available/observable. This led many people to write off the whole sex idea. The prodigious necks may have little to do with food, and everything to do with sex. The big surprise is that there were only a few mutations necessary to give the creature its distinctive physiology. It was later explained by Darwin in “Origin of Species” which changed the world’s perception towards evolution. Do you know mobile radiations can cause cancer? Two forces that drove Giraffe to lengthen their neck is simple – the need to eat and the need to breed. seven. Then the factor of natural selection came into light. The point is, scientists still don’t really know why giraffes have long necks, and it’s unlikely there’s just one simple explanation. However, Rob Simmons and Res Altwegg of the University of Cape Town, also in South Africa, have taken a second look at Mitchell’s results and are not convinced. The theory of the French natur… These changes can be the different evolutionary factors – Genetic drift, gene flow, and mutations. Authorities and the society did not accept Lamarck’s theory as acquired traits never pass to the next generation. Mitchell’s team showed that, in Zimbabwe at least, males and females had necks that were almost exactly the same length, and that if anything the females’ necks were longer. Science with Sam explains. Females choose males for breeding which have a long and strong neck. Their heads, in short, are battering rams, and are quite capable of breaking their opponents’ bones. Once the necks had reached a certain length, males could use them for necking and clubbing – and at that point sexual selection took over, driving the necks to their current extreme lengths. They stand side by side and swing the backs of their heads into each others’ ribs and legs. He discussed it as a “natural tendency towards perfection.”. The problem for the sex idea is that it implies that female giraffes shouldn’t have long necks, and they plainly do. Perhaps the sexual selection explanation for long necks in giraffes isn’t dead after all. Over time, the size of those necks was longer which provide them an adaptation that allowed their survival. The immune system: can you improve your immune age. Darwin was the first to propose that long necks evolved in giraffes because they enabled the animals to eat foliage beyond the reach of shorter browsers. This can sometimes lead to severe injuries or even death. The other idea, developed later than Darwin's and called the sexual selection hypothesis, suggests that the long necks evolved to aid male giraffes in fighting for the attention of females. The classic example that he used as Giraffes. The search for the origin of life: From panspermia to primordial soup. He explained that a Giraffe with its constant strain over a lifetime to stretch its neck as long as they could developed an elongated neck. Before giraffes adapted to having very long necks, this was extremely prevalent because the taller giraffes could reach higher food supply when the food supply grown lower was scarce, whilst the shorter necked giraffes could not reach the food, as shown in Picture A, and thus would not survive. In the savannahs of Africa, it is by necking that … Because a giraffe’s brain is around 2 metres above its heart, the heart has to be big and powerful. praetoriansentry /Flickr ( CC-BY 2.0 ) Most people assume that giraffes’ long necks evolved to help them feed. Why do giraffe's have long necks? Two forces that drove Giraffe to lengthen their neck is simple – the need to eat and the need to breed. They point to a study in Namibia which found that males consistently had heavier necks than females with the same body mass, and that only the males’ necks kept growing throughout their lives. When they reproduced, some of their children were mutated to have longer necks. To help with this, their skulls are unusually thick and they have horn-like growths called ossicones on the tops of their heads. C. Giraffes with longer necks survived because they were better suited to the environment. Scientists have managed to sequence the genome of giraffes, and now have an explanation for their long necks. Furthermore, when it does bend down to drink, the neck has a special collection of valves that keeps the blood rush from knocking the giraffe unconscious. Males’ heads were also heavier than females’, which is what you would expect if they were being selected for their ability to fight. In fact, for the blood to reach the brain it has to be pumped at the highest pressure of any animal. Then the factor of natural selection came into light. If you have a long neck, runs the argument, you can eat leaves on tall trees that your rivals can’t reach. Sauropod dinosaurs trump them easily: the dinosaur Mamenchisaurus, for instance, had a neck over 9 metres long, four times the longest of giraffe necks. Peacocks and birds of paradise aside, there are many birds of which the male seems to have developed colourful plumage as a result of sexual selection, but the females are also brightly coloured. (Image: Tony Heald/Nature Picture Library/Rex Features), Habitat: grasslands and open woodlands of sub-Saharan Africa. Most people assume that giraffes’ long necks evolved to help them feed. One, proposed by Darwin and called the competing browser hypothesis, posits that giraffes evolved long necks to reach food inaccessible to other animals. That seemingly sensible explanation has held up for over a century, but it is probably wrong, says Robert Simmons. Giraffes also have the same number of vertebrates as that of human i.e. seven. It’s a battle between Giraffes where they literally hit each other’s neck to identify the stronger one. Lamarck's idea suggested they stretched their necks and passed the stretching down through generations. The health benefits of sunlight: Can vitamin D help beat covid-19? Journal reference: Journal of Zoology, DOI: 10.1111/j.1469-7998.2010.00711.x. Simmons and Altwegg suggest that giraffes’ necks may have begun growing as a way of eating hard-to-reach food, but that they were then “hijacked” for mating purposes. if the giraffe's long neck was begging to be explained by evolutionary theorists. The latest theory – and it’s a surprise this hasn’t come up before, given biologists’ fixation with it – is that the long necks are the result of sexual selection: that is, they evolved in males as a way of competing for females. The ancestors of giraffes really had short necks. Having a long and powerful neck would be an advantage in these duels, and it’s been found that males with long necks tend to win, and also that females prefer them. Giraffes can reach up to 6 meters tall, and boast long graceful necks. All significant advantages that explain why longer necks were better than shorter necks. eat leaves, shoots, and twigs, unlike grazers who eat small plants and grass. Sexual Selection. It can also go for long periods of time without water. This can sometimes lead to severe injuries or even death. This story, however, is probably wrong. one fact they have long necks to reach high food from trees. The giraffe evolved from an animal which was a dog sized horse type of animal.They were prey to carnivores and so ran away when being pursued. “Necking can determine the stronger neck. The apparently self-evident idea that it was to reach ever-higher food supplies has been challenged in the past 20 years by a competing hypothesis that is it is actually due to sexual selection and competition among fighting males for mates. Giraffes in South Africa do spend a lot of time browsing for food high up in trees, but elsewhere in Africa they don’t seem to bother, even when food is scarce. By consulting scientific research and news articles, Stacker compiled a list of 25 animal evolution questions and answers to explain some evolutionary mysteries, from why giraffes have such long necks to how ants can carry 50 times their body weight. is the change in the frequency of an existing gene variant in a population due to random sampling of organisms. The top 5 Duchenne muscular dystrophy treatments, Opioid overdose: Signs and reasons of overdose, Anger management techniques: 5 tips to start now. Explain how Giraffes may have evolved to have long necks. If giraffes evolved to reach higher branches, we might expect their legs to have lengthened as fast as their necks, but they haven’t. Therefore they would have been more likely to survive and breed. This hypothesis, known as the Lamarck Theory, was introduced in the early 1800s. So there must be a big payback to keep giraffes’ necks so long. They live longer and reproduce more than others. Females choose males for breeding which have a long and strong neck. Hence, they have a higher chance to pass their traits to the next generation. Fossil evidence supplies further backing for his hypothesis: it appears that giraffes developed their long necks between fourteen and twelve million years ago, a period during which Africa underwent a general aridification and its forests gave way to savannah. He discussed it as a “natural tendency towards perfection.” Lamarck concluded that animals evolve new traits that help them survive in the changing environment. It’s a battle between Giraffes where they literally hit each other’s neck to identify the stronger one. Among these organisms are the giraffes. Darwin proposed that these traits developed by a random chance. The giraffe has adapted for this difficulty by drinking from dew and getting much of its water from the food it eats. The more likely reason a giraffe has a long neck is not so it can reach high leaves; this is consequential and secondary to the primary evolutionary driving force. ... 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Male giraffes fight for females by “necking”. Giraffes with longer necks could reach long heights and had better nutrition than the Giraffes with shorter ones. Latest Happenings in the World of Science, Giraffes are browsers i.e. Read on to find out how evolution has led to the diversity of animals on the planet. The elongation of the giraffe’s neck is by its constant struggle to lengthen its neck to reach the leaves at the top. Sadly, that’s a myth! The classic example that he used as Giraffes. ... Over millennia the necks of the ancestors of giraffe gradually elongated. But there is another possibility. Each vertebrate is one foot long, unlike humans. It is commonly believed that giraffes developed long necks in order to win fights. Correct answers: 3 question: Natural selection leads organisms to become adapted to theirenvironment over time. It states that the food on the ground was scarce and that these animals were instinctively raising their necks as high up as they could to reach what was there. Each vertebrate is one foot long, unlike humans. The “necks for sex” idea also helps explain why giraffes have extended their necks so much more than their legs. There would be variation in the length of necks in the early giraffe population. The tallest living land animal, a giraffe stands between 4.5 and 5 metres tall – and almost half that height is neck. Around 15 million years ago, antelope-like animals were roaming the dry grasslands of Africa. “Necking can determine the stronger neck. The standard story about why giraffes have evolved their incredibly long necks states that this trait has helped them in reaching to higher leaves. The long neck of the giraffe is supported with extremely strong anchoring muscles which … First, a discussion of the contentious topic of why giraffe evolved to have a long neck. They say the figures do show that males have proportionally longer necks, and that “Mitchell et al. The giraffe may have a long neck for an adaptionist reason, or this feature may have come about as an exaptation, something that evolved who-knows-why and was later adapted for its current use." For years, there has been scant fossil evidence showing how the giraffe evolved to have such an admirably long neck. An adaptation is a trait or behavior helping an organism to survive. He explained that a Giraffe with its constant strain over a lifetime to stretch its neck as long as they could developed an elongated neck. There was nothing very special about them, but some of their necks were a bit long. The consequence is a 2 meter long neck for a giraffe. The more fundamental question of why giraffes evolved their long necks remains open, however. How did the giraffes develop such a long neck? 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. Within a mere 6 million years, they had evolved into animals that looked like modern giraffes, though the modern species only turned up around 1 million years ago. Several theories have been developed to explain how the giraffe’s neck evolved. The Lamarckian theory states that a change in an organism can pass to the offspring. “Necking can determine the stronger neck. Those who had longer necks would have an advantage for survival as they would be able to reach higher into the trees to feed. The consequence is a 2 meter long neck for a giraffe. The giraffes have been able to adapt to overpopulation that result in limited strategic resources (Keller et al., 2009). Hence, they have a higher chance to pass their traits to the next generation. 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