Chapter 2: “Reproduction and Survival” Lesson 1: “Reproduction” Life Science Chapter 2: “Reproduction and Survival” Lesson 1: “Reproduction”

What are sexual and asexual reproduction? Reproduction involves the transfer of genetic material from parent to offspring. Sexual reproduction is the production of a new organism from two parents. It requires a sperm cell from a male and an egg cell from a female which join together to form a single unit in a process called fertilization. The fertilized egg cell contains genetic material from both parents. The offspring will receive some characteristics, or traits, from each parent. All mammals reproduce sexually.

What are sexual and asexual reproduction? (continued) Asexual reproduction is the production of a new organism from a single parent. It produces an offspring that has the same genetic information as the parent meaning the offspring is identical to the parent. There are organisms in all six kingdoms that reproduce asexually. Examples include all members of the bacteria and archaea kingdoms and most unicellular protists. Most fungi and many plants reproduce asexually during a part of their lives and sexually during another. Animals such as jellyfish, corals, worms, and some echinoderms can form new offspring asexually. Some lizards, frogs, fish, and insects can also reproduce asexually.

How do organisms reproduce asexually? Most unicellular protists and bacteria reproduce simply by splitting into two cells. Before splitting, the organism copies its own genetic material. The two new offspring organisms will then each have a copy of the genetic material they need to carry out life processes. Some organism can reproduce through budding. Examples include cnidarians, sponges, and some fungi. During budding, a small part of the parent’s body grows into a tiny and complete version of the parent. In some cases, the bud breaks off from the parent organism and continues to grow. In other organisms, such as coral, the newly formed bud remains attached to the parent.

How do organisms reproduce asexually? (continued) Some species of fish, insects, frogs, and lizards go through asexual reproduction in a different way. The females produce egg cells that would normally be fertilized by sperm cells. However, fertilization never takes place. These egg cells develop into a new organism without fertilization. An example would be the queen honey bee who lays eggs, some of which are fertilized and some that are not. The fertilized eggs develop into females while the unfertilized eggs develop into males

How do organisms reproduce asexually? (continued) Many plants can undergo a form of asexual reproduction called vegetative propagation. Vegetative propagation produces new plants from leaves, roots, or stems. Many plants commonly reproduce this way by producing runners. Runners are plant stems that lie on or under the ground and sprout up as new plants. Runners can also grow downward from hanging plants.

How do organisms reproduce asexually? (continued) Budding in hydra Budding in coral Splitting Vegetative Propagation in strawberries

How do plants and animals reproduce? When plants and animals reproduce sexually, a fertilized egg develops into an embryo which is the beginning of a new offspring. Flowers are the reproductive structures of many plants. Fertilization takes place in the ovary. A seed coat forms around the embryo to protect it. Some plants, called conifers, have seeds protected in a cone, so they do not have flowers. Once seeds are formed, they must be dispersed. Seeds are dispersed through wind, water, and through the digestive system of animals who eat the plants in which the seeds are contained.

How do plants and animals reproduce?

How do plants and animals reproduce?(continued) Animals that reproduce sexually begin as fertilized eggs that develop into an embryo. The embryos get food from the yolk of the eggs. Monotremes such as the duck-billed platypus are the only mammals that lay eggs. All other mammals give birth to live young.

How do fungi reproduce? Yeast are unicellular fungi that reproduce asexually by budding. Fruiting bodies are fungal structures that produce spores.

How do sexual and asexual reproduction compare? Asexual reproduction is convenient in that an organism does not have to depend on another organism. Organisms that reproduce asexually tend to be well-suited to their environment and produce equally as well-suited offspring. One major advantage of sexual reproduction is that it promotes variety in a species. This can give rise to offspring that are better suited to environmental changes than their parent.