Example: Giraffes with the longest necks are able to reach more leaves to each. Selective pressures will work in the advantage of the longer neck giraffes and therefore the distribution of the trait within the population will shift towards the longer neck trait.
What type of selection is shown by giraffes?
This is ‘natural selection‘. 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. Thanks to their long necks, they were able to reach leaves high up in the trees in their environment.
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.
Why do giraffes have long necks quizlet?
Giraffes stretched their necks in order to reach food. With continual stretching most giraffes now have long necks. … Struggle to exist causes long-necked giraffes to have the most offspring. Due to natural selection, most giraffes now have long necks.
What is the function of a giraffe’s long neck?
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.
Why do giraffes who make their necks longer by stretching them not give birth to giraffes with similarly longer necks the babies grow up to have very similar sized necks?
Lamarck claimed that these used to all have short necks until a drought came and destroyed all the low-growing plants; because the lower animals ate what was left of the lower plants, giraffes had to stretch their necks to reach the upper leaves of trees; in theory, this stretching caused their necks and front legs to …
Why do giraffes have long necks According to Lamarck?
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.