What Are Three Ways Animals Reproduce?

This planet holds a diverse variety of life. In turn, organisms have evolved different methods of reproduction to suit their needs and environment. Sexual reproduction requires two gametes to fuse in order to produce offspring. Animals have varying methods of reproduction, each having evolved to ensure the most effective continuation of their species.

  1. Egg Layers

    • Penguins lay eggs.

      Most amphibians are egg layers; for example, the toad lays eggs. The same goes for fish, where only a few species give birth to live offspring -- the shark is one of these. All birds are egg layers. When a bird is about to lay an egg, the egg travels along her oviduct. The bird needs to mate to fertilize the egg before the last layers of egg white and two layers of membranes are laid down. The egg then hardens.

    Bearers of Live Young

    • Humans are bearers of live young.

      Nearly all mammals bear live young rather than depositing eggs. Mammals, such as the horse or dolphin, mate and then an embryo develops within the mother's uterus. Very few egg-laying mammals exist, one example is the duck-billed platypus. A few species of fish, belonging to the live-bearer family, give birth to live young. These include the guppy and swordtail. As with other bearers of live young, sexual reproduction takes place by the male fertilizing the egg while within the female.

    Asexual Reproduction

    • Flatworms reproduce asexually.

      Asexual reproduction differs from sexual reproduction (where both male and female cells combine together) in that reproduction takes place without the interaction between two sexes. Only one parent produces offspring, which are often identical. The parent does this by releasing a mass of cells that grow into offspring, or the parent itself divides into sections and grows into new individuals. Sea anemones and sponges reproduce asexually.

    External Fertilization

    • Amphibians and fish often reproduce through external fertilization. Only animals that live in water reproduce this way. Gametes (eggs and sperm) are released into the water by the male and female, the sperm then swim towards the eggs for fertilization to take place. Offspring then develop in the water.