How would JB Lamarck explain why giraffes have long necks?
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.
How did natural selection affect giraffes?
A classic example of natural selection at work is the origin of giraffes’ long necks. The longer-necked giraffes reproduced more, so in the next generation longer necks were more common. Over many generations this process produced giraffes as they are today.
What animal did the giraffe evolve from?
Some scientists have long presumed today’s giraffe (Giraffa camelopardalis, right), which includes a handful of subspecies scattered throughout sub-Saharan Africa, evolved from an animal that looked like its close cousin the okapi (Okapia johnstoni, left), which lives in the tropical forests of central Africa.
How do giraffes defy evolution?
There are many animals that defy evolution and the bull giraffe is one of them. The circulatory system of only its neck is made with complexity in which evolution cannot create. The bull giraffe has a huge heart that pumps blood up its long neck. The blood pumped to its brain up the neck defies gravity.
What do giraffes use their necks for?
Feeding. With the aid of its long neck, a giraffe is able to reach leaves, fruit and flowers high up in Vachellia or Senegalia (formerly Acacia) and other sought after tree species. Giraffe are thus equipped to exploit a band of foliage beyond the reach of all other terrestrial browsers, except for elephant.
What type of selection would include the evolution of a long neck in giraffes quizlet?
Giraffes evolved by Natural Selection to have long necks due to the 3 key conditions of Natural Selection that were present in their time. The first key condition present was the struggle for existence. This is when there are more individuals that can survive in an area.
Why is the giraffe an example of evolution?
Consider the giraffe, for example. A Darwinian theory of evolution posits that it was through random variation that some giraffes had longer necks than others. Because they could access food, the giraffes with longer necks were better able to survive and reproduce, with their offspring inheriting their long necks.
What type of selection would lead to the evolution of a long neck for giraffes quizlet?
Long necks is a heritable trait that would allow the stronger giraffes to survive and reproduce more offspring (fitness). This is directional selection because it drives the average of the population in one direction, in this case, toward longer necks.
How does a giraffe neck work?
In the upper neck, a complex pressure-regulation system called the rete mirabile prevents excess blood flow to the brain, when the giraffe lowers its head to drink. In other animals, such pressure would force the blood out through the capillary walls.
Why do giraffes fight with their necks?
In intense bouts, male giraffes compete for dominance by steadying their legs and swinging their necks to deliver sledgehammer blows to each other with the stout ossicones atop their heads. For a time, it seemed that this violent behavior might be the secret to why giraffes are so oddly proportioned.
How does a giraffe neck help it survive?
Since these shorter creatures pick over food at a lower level, giraffes’ necks allow them to reach food and nutrients that others cannot. This becomes especially important for survival in habitats where food can become scarce and droughts are fairly common.
Why do giraffe have such a long neck?
One example is the giraffe, or rather its improbably long neck. It appears obvious: the giraffe’s neck, which can grow to as much as two metres in length, has been selected because it gives its owner exclusive access to the topmost leaves of the trees, and no other animal can reach them.
How did the giraffes evolve to have long necks?
Additional information
Why do giraffes have such long necks?
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. In the savannahs of Africa, it is by necking that male giraffes combat to win females.
How the giraffe got its long neck?
Their very long necks are an adaption to feeding at high levels in the treetops. Their physical adaption, a long neck, does not only help them to graze but also helps them keep track of predators and it enables visual communication with other giraffe over several miles. How long ago did giraffes have short necks?