Glossary: F-H

Gene

Definition: A unit of heredity which is transferred from a parent to offspring and is held to determine some characteristic of the offspring. Genes are segments of DNA that contain the instructions for building proteins. Proteins are the workhorses of the cell and carry out a wide variety of functions.

Examples:

• Eye Color: The gene for eye color determines whether a person has blue, brown, or green eyes.
• Hair Color: The gene for hair color determines whether a person has black, brown, blond, or red hair.
• Height: The gene for height determines how tall a person will be.

Context/Function: Genes are the basic units of heredity. They are passed from parents to offspring and determine the traits of an individual. The study of genes is called genetics.

Genetics

Definition: The study of heredity and the variation of inherited characteristics. Genetics is a broad field that includes the study of genes, genomes, and the molecular basis of inheritance.

Examples:

• Classical Genetics: The study of how traits are passed from parents to offspring.
• Molecular Genetics: The study of the structure and function of genes at the molecular level.
• Population Genetics: The study of the genetic composition of populations and how it changes over time.

Context/Function: Genetics is a fundamental science that has a wide range of applications, from medicine to agriculture. It is used to diagnose and treat genetic diseases, to develop new crops and livestock, and to understand the evolution of life on Earth.

Habitat

Definition: The natural home or environment of an animal, plant, or other organism. A habitat provides the resources that an organism needs to survive, such as food, water, and shelter.

Examples:

• Forest: A habitat for a wide variety of plants and animals, including trees, birds, mammals, and insects.
• Desert: A habitat for plants and animals that are adapted to dry conditions, such as cacti, camels, and lizards.
• Ocean: A habitat for a wide variety of marine life, including fish, whales, and dolphins.

Context/Function: The habitat of an organism is a critical factor in its survival. If a habitat is destroyed or degraded, the organisms that live there may not be able to survive.

Heterotroph

Definition: An organism that cannot manufacture its own food and instead obtains its food and energy by taking in organic substances, usually plant or animal matter. Heterotrophs are the consumers in a food chain.

Examples:

• Animals: All animals are heterotrophs. They eat plants or other animals to get the energy and nutrients they need to survive.
• Fungi: Fungi are heterotrophs that absorb nutrients from their surroundings.
• Bacteria: Some bacteria are heterotrophs that break down organic matter.

Context/Function: Heterotrophs play an important role in ecosystems by consuming other organisms and releasing nutrients back into the environment. They are a vital part of the food web.

Homeostasis

Definition: The tendency toward a relatively stable equilibrium between interdependent elements, especially as maintained by physiological processes. Homeostasis is the ability of an organism to maintain a constant internal environment, despite changes in the external environment.

Examples:

• Thermoregulation: The ability of an organism to maintain a constant body temperature.
• Osmoregulation: The ability of an organism to maintain a constant water balance.
• Glucoregulation: The ability of an organism to maintain a constant blood sugar level.

Context/Function: Homeostasis is essential for the survival of all living organisms. It allows organisms to function properly, even when the external environment is changing.

Hormone

Definition: A regulatory substance produced in an organism and transported in tissue fluids such as blood or sap to stimulate specific cells or tissues into action. Hormones are chemical messengers that are produced by the endocrine glands.

Examples:

• Insulin: A hormone that regulates blood sugar levels.
• Testosterone: A hormone that is responsible for the development of male secondary sexual characteristics.
• Estrogen: A hormone that is responsible for the development of female secondary sexual characteristics.

Context/Function: Hormones play a vital role in regulating a wide variety of bodily functions, including growth, metabolism, and reproduction. They are essential for maintaining homeostasis.