Who believed that giraffes have long necks because?
In short, giraffes’ long necks are the result of generation upon generation of repeated stretching and inheritance. The English naturalist Charles Darwin also thought the giraffe’s extraordinary legs and neck must have something to do with foraging.
Who believes that giraffes have long necks because they have stretched?
5) Bob believes that giraffes have long necks because they have stretched their necks to try and reach food that is high in trees.
How did giraffes get their long necks According to anthropologists?
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.
Why do modern giraffes have 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.
When did giraffes have short necks?
According to the known swath of fossil giraffes, significant neck elongation began around 14 million years ago during the Late Miocene – after the lineage to which the relatively short-necked okapi split off – and by about 5 million years ago giraffes of modern proportions had evolved.
Why did Darwin think giraffes had long necks?
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. That seemingly sensible explanation has held up for over a century, but it is probably wrong, says Robert Simmons.
Which is the only mammal with a long neck?
There is no denying that giraffes have the longest necks when it comes to present-day mammals, but there have been longer necks in the past. For instance, the Mamenchisaurus dinosaurs had a neck that stretched over 10 meters long, 4-5 times the neck length of present-day giraffes. Now, such a long neck does come with its own risks.
Is there evidence that giraffes have long necks for sex?
However, in the last 10 years evidence has emerged that weakens the necks-for-sex hypothesis. In particular, a 2013 investigation found no evidence that males have longer necks for their body mass than do females. In other words, there is no obvious sexual dimorphism in neck length.
How did a giraffe get his neck cut off?
In an extreme case, reported in the 1960s, one male punctured his opponent’s neck just below the ear. The impact splintered a vertebra and a shard of bone entered the luckless giraffe’s spinal column, killing him.
How did Lamarck explain the evolution of giraffes?
He believed that traits changed or acquired over an individual’s lifetime could be passed down to its offspring. Giraffes that had acquired long necks would have offspring with long necks rather than the short necks their parents were born with. This type of inheritance, sometimes called Lamarckian inheritance,…
How did the giraffe’s neck change over time?
Lamarck believed that the stretching elongated the giraffe’s neck, which became a useful characteristic and was passed onto future generations. This resulted in the length of the giraffe’s neck increasing over time.
How did giraffes get their arms and legs?
For example, giraffes developed their elongated necks and front legs by generations of browsing on high tree leaves. The exercise of stretching up to the leaves altered the neck and legs, and their offspring inherited these acquired characteristics.
Which is part of Lamarck’s mechanism for evolution?
The second part of Lamarck’s mechanism for evolution involved the inheritance of acquired traits. He believed that traits changed or acquired over an individual’s lifetime could be passed down to its offspring. Giraffes that had acquired long necks would have offspring with long necks rather than the short necks their parents were born with.