Introduction
A life cycle is the changes in which an organism grows and develops to reproduce and start another generation of that species, on its way into adulthood (Utah Education Network, n.d.). An animal life cycle is the span of an animal’s life from before birth to death. It can also be classified as the end of one generation and beginning to a new one (a-z animals, 2015b). Life cycles differ in many ways, from the different animals, to the different species of that animal. A life cycle is a circle from birth to death and goes through the life of the organism and the span of the life cycle depends on the animal’s body size, because those that live longer are not weak or vulnerable (a-z animals, 2015b). Through the life cycle, an animal develops, grows and reproduces. The start of a life cycle for most animals begins as an egg, fertilized by a sperm cell. Then the animal grows in to an adult and mates, and then it reproduces. Mating is necessary for reproduction, which is needed for a species of animal to evolve and survive (a-z animals, 2015b). All animal life cycles start the same way, through birth either being live or in an egg, but life cycles end in different ways depending on the animal. For many animals, the reproductive stage is the end (a-z animals, 2015b). Some animals reproduce and give birth to new animals by laying eggs and others give live birth. There are two main types of animals, vertebrates and invertebrates.
Invertebrate or Vertebrate
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Amphibian
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An invertebrate is an animal without a back bone or spinal column and a vertebrate is an animal with a back bone and/or spinal column. A few animals under the classification of invertebrate are crabs, spiders, octopus or insects, and vertebrate animals are fish reptiles, birds, mammals, rodents or amphibians (Reference Library, 2012). “Only about 3% of all animal species give birth to live young as part of their life cycle” (Utah Education Network, n.d., para. 1). Most animals give birth by laying an egg, some reptiles, and a select few amphibians can give both live birth and lay eggs (Roche, 2015; Sheppard Software, n.d.).
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Amphibians include frogs, toads and newts. Amphibians are a more complex classification of animal because they go through the life cycle in a form of metamorphosis, meaning big change, which is why tadpoles look completely different from an adult frog (Guenther, 2015; National Wildlife Federation, 2015; Sheppard Software, n.d.). The word amphibian means double life. If animals are amphibious, they spend most of their time between water and land and can have birth on either (a-z animals, 2015a; National Wildlife Federation, 2015; Sheppard Software, n.d.). Amphibians are known for spending most of their childhood time underwater, using gills to breathe, and, as they grow, they move on to land and breathe with fully grown lungs (a-z animals, 2015a; Guenther, 2015; Roche, 2015).
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Find different types of butterflies and the stages of a butterflies life buy clicking on the picture to the right or the button below.
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