AP BIOLOGY

EVOLUTION

SOURCES OF VARIATION IN A POPULATION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
A giraffe has a long neck. Why would the giraffe need this adaptation?
A
to keep warm
B
to reach food high above the ground
C
to have room to eat more
D
to catch birds
Explanation: 

Detailed explanation-1: -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.

Detailed explanation-2: -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.

Detailed explanation-3: -A giraffe’s long neck is an adaptation that helps the giraffe reach foods that other animals can’t eat, such as leaves that are very high up in trees.

Detailed explanation-4: -Height and Size. Giraffes use their height to good advantage and browse on leaves and buds in treetops that few other animals can reach (acacias are a favorite). Even the giraffe’s tongue is long! The 21-inch tongue helps them pluck tasty morsels from branches.

Detailed explanation-5: -They are the world’s tallest mammals. They are uniquely adapted to reach vegetation inaccessible to other herbivores. Unusually elastic blood vessels and uniquely adapted valves help offset the sudden buildup of blood (to prevent fainting) when giraffes’ heads are raised, lowered, or swung quickly.

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