Chapter 2 Parents and Offspring

Regeneration Healing, after scraping a knee is a type of regeneration. Skin cells divide, and regenerated skin grows over the injury. In humans, regeneration is limited mostly to healing wounds. Plants and some animals, however, can regenerate major body parts!

Lesson 1 Reproduction Sexual Reproduction: the production of a new organism from two parents. Male and female cells join together in fertilization to form a new individual with characteristics, or traits, from each parent. Has anyone ever told you, “you look just like your mother, or father did at that age!”

Sexual Reproduction Meiosis: Division of cells in which four “daughter” cells are produced from one “parent” cell, each with half the genes of the parent. Meiosis allows for the combining of genetic materials from both parents to occur in the offspring.

Meiosis

Lesson 1 Reproduction Asexual Reproduction: Mitosis Mitosis: The entire process of cell division including division of the nucleus and the cytoplasm to make an exact copy of itself. Many one-celled organisms, such as bacteria and protoza, reproduce by simple cell division or fission. Fission: the division of an organism into new organisms as a process of reproduction.

Mitosis

Asexual Reproduction Budding: a small part of the parent’s body grows into a tiny and complete version of the parent. The bud breaks off from the parent organism and continues to grow as a complete copy of the parent.

Budding of a Hydra

Asexual Reproduction Some species of fish, insects, frogs, and lizards produce eggs that just develop into a new animal without fertilization. Bees: when a queen honeybee lay eggs, some are fertilized and others are not. The fertilized eggs develop into females, or worker bees. The unfertilized eggs become males, or drone bees.

Asexual Reproduction Vegetative Propagation: Runners, rooting, cuttings, that are able to form a new plant. Each new plant is an exact copy of the parent plant.

Vegetative Runners