How are giraffes an example of natural selection?
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 was Darwin’s theory of natural selection?
More individuals are produced each generation that can survive. Phenotypic variation exists among individuals and the variation is heritable. Those individuals with heritable traits better suited to the environment will survive.
Are giraffes directional selection?
An example of directional selection is giraffe neck lengths. The environment created a selection pressure which favored giraffes with longer necks who could reach more food in the trees. At the same time, there was selection pressure against giraffes with shorter necks.
Is giraffe neck natural selection?
The giraffe’s long neck is a perfect adaptation to the animal’s natural habitat. Clearly the giraffe evolved this uncommon and helpful trait in order to reach those nourishing leaves. That’s how natural selection works.
What is natural selection examples?
Natural selection is the process in nature by which organisms better adapted to their environment tend to survive and reproduce more than those less adapted to their environment. For example, treefrogs are sometimes eaten by snakes and birds.
Why do we now see only giraffes with long necks?
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. This, then, is an adaptation designed to avoid competition for food with other animals.
Who gave the theory of natural selection?
Charles Darwin
The theory of evolution is a shortened form of the term “theory of evolution by natural selection,” which was proposed by Charles Darwin and Alfred Russel Wallace in the nineteenth century.
What are the 3 natural selection?
The 3 Types of Natural Selection
- Stabilizing Selection.
- Directional Selection.
- Disruptive Selection.
What are the 4 types of natural selection?
Stabilizing, Directional, and Diversifying Selection. Stabilizing, directional, and diversifying selection either decrease, shift, or increase the genetic variance of a population.
Does a giraffe have more bones in its neck than a human?
Even though the neck of a giraffe can be eight feet long and weigh up to 600 pounds, they only have seven neck vertebrae – the same number of neck bones that humans have! These large vertebrae link together to form those famous long necks we all know and love.
Why are there no short-necked giraffes?
But although their necks can measure up to 1.8 metres (6 feet) alone, they have, like most mammals, just seven neck vertebrae. Fossil evidence shows that, once upon a time, giraffes had much shorter necks. Lamarck’s idea suggested they stretched their necks and passed the stretching down through generations.
How did the evolution of the giraffe coincide with natural selection?
Evolution of the giraffe coincides with natural selection as overtime, the giraffes with shorter necks died out and only the giraffes with longer necks could survive and find mates to successfully reproduce with. It has also been reported that, as shown in Picture C, the giraffe and the okapi evolved from a common ancestor referred to as…
Why are giraffes with longer necks more likely to reproduce?
Of course this relates the the size of the giraffes necks again, as the ones with longer necks could not only reach the higher, abundant food source but attracted more mates, and therefore reproduced while the short-necked giraffes did not. There are now nine giraffe subspecies including the Reticulated giraffe and the Nigerian giraffe.
How did the okapi and the giraffe evolve?
Summary: As shown in the evolutionary tree (Picture C), giraffes and okapis evolved from a common ancestor, the pre-okapi. This has substantial evidence as the okapi is the only close relative to the giraffe and their skulls, as shown in picture D, are very identical.
How is the Nigerian giraffe different from other species?
While there are not many differences between the sub-species, some have adapted to different climates or weather patterns. For example, the Nigerian giraffe has adapted to the rainy Nigerian climate and the Reticulated giraffe has adapted to the dry savanna climate.