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Today we are going to talk about how vertebrate animals breathe.

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Breathing is an exchange of two gases, oxygen and carbon dioxide.

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It means taking in oxygen and expelling carbon dioxide.

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Fish take in oxygen from water that enters through the mouth and leaves through the gills.

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The exchange of gases happens through the capillaries that fish have in the gills.

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Birds get oxygen from the air. They have lungs where there are alveoli with capillaries.

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Reptiles taking oxygen from the air. They use lungs to take the oxygen.

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The exchange of gases happens in the alveoli.

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Mammals taking oxygen from the air. Air passes into the lungs.

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Through the capillaries there are in the alveoli in the lungs the exchange of gases happens.

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Young amphibians use gills. They take in oxygen from water because they are apoptic.

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During metamorphosis, when the young amphibian turns into an adult, gills close and lungs are developed.

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Adult amphibians use their lungs and moist skin to breathe.