8 résultats pour "butterflies"
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Butterflies.
When the change is complete, the adult butterfly splits the chrysalis. The insect unfolds its wings andpumps blood and air into them. It spreads out the wings until they dry and harden. The beautifulbutterfly then flies off to slurp nectar from flowers. Most butterflies live only one or two weeks. BUTTERFLY RELATIVES Butterflies are closely related to moths, another type of insect. One difference between butterflies andmoths is how their antennae look. Butterflies have knobs called clubs on the...
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Butterflies and Moths - biology.
The smallest butterflies are certain blues that have wingspans of a mere 0.7 cm (0.25 in). The largest are the female giant birdwings of Papua New Guinea, whichmeasure up to 30 cm (12 in) across. Moths range in size from tiny Microlepidoptera, several groups of small moths with wings no more than 0.16 cm (0.06 in) across, togiant silk moths, such as the atlas moth, which may exceed 30 cm (12 in) in wingspan. IV REPRODUCTION AND LIFE CYCLE Butterflies locate potential mates by sight, identifyin...
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Insect - biology.
they almost always have six legs. In some insects, such as beetles, the legs are practically identical, but in other insects each pair is a slightly different shape. Still otherinsects have specialized leg structures. Examples are praying mantises, which have grasping and stabbing forelegs armed with lethal spines, and grasshoppers andfleas, which have large, muscular hind legs that catapult them into the air. Mole crickets’ front legs are modified for digging, and backswimmers have hind legs de...
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Insects.
parents. It does not have wings. It may not even have legs. As the insect grows, it starts to changeshape. This change is called metamorphosis. There are two kinds of metamorphosis, called incompleteand complete. Dragonflies, grasshoppers, and crickets are some insects that go through incomplete metamorphosis asthey grow up. The young insects are called nymphs or naiads. The young insect molts, or crawls out ofits exoskeleton, as it grows bigger. It grows a new, larger exoskeleton. Its body chan...
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Evolution - biology.
genetic diversity to extinction. Sexual reproduction ensures that the genes in a population are rearranged in each generation, a process termed recombination. Although the combinations of genes inindividuals change with each new generation, the gene frequency, or ratio of different alleles in the entire population, remains relatively constant if no evolutionaryforces act on the population. One such force is the introduction of new genes into the genetic material of the population, or gene pool...
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Animal Migration.
No one understands exactly how migrating animals know when to migrate or how they find their way.Some experts think that the shortening days in fall or the lengthening days in spring may act as a signalto birds and other animals. Such signals indicate that it is time to start their long journey. Once on their way, birds are thought to navigate by the Sun and stars. Research shows that birds alsomay be sensitive to Earth’s magnetic field—the space around Earth where a magnetic force is felt. Fish...
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Invertebrate - biology.
animals with a five-pointed design. They live in the sea and move with the help of tiny fluid-filled feet—another feature found nowhere else in the animal world. Zoologists recognize several different groups of worms. The phylum known as flatworms contains the simplest animals possessing heads. Nerves and sense organs areconcentrated in the head. Most flatworms are paper-thin and live in a variety of wet or damp habitats, including the digestive systems of other animals. Roundwormsrepresent anot...
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Invertebrate - biology.
animals with a five-pointed design. They live in the sea and move with the help of tiny fluid-filled feet—another feature found nowhere else in the animal world. Zoologists recognize several different groups of worms. The phylum known as flatworms contains the simplest animals possessing heads. Nerves and sense organs areconcentrated in the head. Most flatworms are paper-thin and live in a variety of wet or damp habitats, including the digestive systems of other animals. Roundwormsrepresent anot...