FUNGI DEFINITION | Fungi are organisms that lack chlorophyll.

FUNGI DEFINITION

Definition of Fungi are organisms that lack chlorophyll, the green coloring matter that many plants use to make food. Fungi cannot make their own food. Instead, they absorb food from their surroundings. There are over 70,000 species of fungi. Yeasts and other one-celled fungi are too small to be seen without a microscope. But most types can be seen with the unaided eye. Some of the most common fungi include mildews, molds, mushrooms, and plant rusts.

 Fungi Pictures

Fungi structure : Parts of a fungus. 

Fungi structure Except for yeasts and other one-celled fungi, the main part of a fungus consists of thousands of threadlike cells called hyphae. These tiny, branching cells form a tangled mass called a mycelium. In many kinds of fungi, the mycelium grows beneath the surface of the material on which the organism is feeding. For example, the mycelium of a mushroom often grows just beneath the surface of the soil. The umbrella-shaped growth known as a mushroom is actually the fruiting body of the fungus. The fruiting body produces cells called spores, which develop into new hyphae. Spores are smaller and simpler than the seeds of plants, but both enable an organism to reproduce.

Some bread molds and microscopic species of fungi bear spores in tiny structures called sporangia. In black bread mold, the sporangia form at the tips of upright hyphae called sporangiophores. Other hyphae called stolons spread over the surface of the bread. They are anchored by rhizoids (rootlike structures). Groups of sporangia usually form above the rhizoids.

Fungi Pictures

Fungi characteristics How a fungus lives. 

Fungi characteristics  Fungi live almost everywhere on land and in water. Some fungi are parasites that feed on living plants and animals. Other fungi, called saprophytes, live on decaying matter. Still other fungi live together with other organisms in ways that are mutually beneficial. Such a relationship is called symbiotic. For example, a fungus and an organism called an alga may live together symbiotically to form a lichen. Some fungi also live with the roots of plants in a symbiotic relationship known as a mycorrhiza. The fungus takes carbohydrates from the plant. In return, the fungus helps supply the plant with water and such important minerals as phosphorus, potassium, iron, copper, and zinc. Most species of trees, shrubs, and herbs have mycorrhizal relationships with fungi.



Mycorrhiza is the symbiotic association of the mycelium of certain fungi with the roots of certain higher plants,living in close relationship with the surface cells. Ex. It is possible with many, if not all, species of plant which normally form mycorrhizas in natural conditions to grow them in artificial surroundings without their appropriate fungi.

Fungi cannot produce their own food because they do not contain chlorophyll. They take carbohydrates, proteins, and other nutrients from the animals, plants, or decaying matter on which they live. Fungi discharge chemicals called enzymes into the material on which they feed. The enzymes break down complex carbohydrates and proteins into simple compounds that the hyphae can absorb.

Fungi Pictures

Types of Fungi.

Most kinds of fungi reproduce by forming spores. Some spores are produced by the union of gametes (sex cells). Others, called asexual or imperfect spores, are produced without the union of gametes. Many fungi produce spores both sexually and asexually. Many spores are scattered by the wind, and others are transported by water or by animals. Mushrooms and some other fungi forcefully discharge their spores. A spore that lands in a favorable location germinates (starts to grow) and eventually produces a new mycelium.

Types of Fungi. Yeasts can reproduce by forming spores, but many kinds of yeasts reproduce by budding. When a yeast buds, a bulge forms on the cell. A cell wall grows and separates the bud from the original yeast cell. The bud then develops into a new cell. Budding produces a large number of yeast cells rapidly.

Definition of Territoriality

Territoriality is a form of animal behavior in which an individual animal or a group defends an area against other members of the same species or against members of other species. The defended area is called a territory. An individual usually wins encounters with intruders while on its own territory, but it usually loses encounters when intruding onto another territory. A territory contains resources that the animal needs to survive and reproduce. These resources may include shelter, food, and water; places where mates can be found; and places where animals can escape from their enemies.

Definition of Territoriality is common in vertebrates (animals with a backbone), including fish, amphibians, reptiles, birds, and mammals. It is less common among insects and other invertebrates (animals without a backbone).

The size of a territory varies, depending on the effort required to defend the area and the resources available. Animals may establish small territories in the immediate vicinity of nesting sites or in areas of abundant food. They may claim large territories when resources are widely scattered. The period a territory is held may vary from less than a day to many years or a lifetime.

Animals may defend a territory by being openly aggressive, such as by chasing and fighting intruders. They also may defend the territory through signals of potential aggression. For example, a wolf marks out its territory by urinating on bushes, rocks, and other objects. The scent of urine warns intruders of the wolf's presence and the risk of an encounter. The more aggressive forms of defense generally are used when the intruder is especially persistent.

DEFINITION OF SEED

Definition of Seed is the specialized part of a plant that produces a new plant. It contains an embryo (partly developed plant) that consists of an immature root and stem. A seed also has a supply of stored food and a protective covering.

Seeds are produced by approximately 250,000 kinds of plants. Flowering plants make up the largest group of seed-producing plants. These plants, which botanists call angiosperms, include the vast majority of trees, shrubs, and soft-stemmed plants. Seeds are also produced by about 800 kinds of trees and shrubs called gymnosperms. Most gymnosperms develop cones.

The seeds of different kinds of plants vary greatly in size. The double coconut tree produces the largest seed, which weighs up to 50 pounds (23 kilograms). On the other hand, orchid seeds are so tiny that 800,000 of them weigh no more than an ounce (28 grams). The size of a seed has no relationship to the size of the plant that develops from it. For example, the giant redwood tree grows from a seed only 1/16 inch (1.6 millimeters) long.

The number of seeds produced by an individual plant varies according to the size of the seeds. A coconut tree has only a few large seeds, but an orchid or pigweed plant produces millions of tiny ones.

Definition of Photosynthesis

Definiton of Photosynthesis, is a food-making process that occurs in green plants. Photosynthesis is the chief function of leaves. The word photosynthesis means putting together with light.




Green plants use energy from light to combine carbon dioxide and water to make food. All our food comes from this important energy-converting activity of green plants. Light energy is converted to chemical energy and is stored in the food that is made by green plants. Animals eat the plants, and we eat animal products as well as plants. The light used in photosynthesis is absorbed by a green pigment called chlorophyll. Each food-making cell in a plant leaf contains chlorophyll in small bodies called chloroplasts.

In chloroplasts, light energy causes water drawn from the soil to split into molecules of hydrogen and oxygen. In a series of complicated steps, the hydrogen combines with carbon dioxide from the air, forming a simple sugar.

 

Oxygen from the water molecules is given off in the process. From sugar--together with nitrogen, sulfur, and phosphorus from the soil--green plants can make starch, fat, protein, vitamins, and other complex compounds essential for life. Photosynthesis provides the chemical energy needed to produce these compounds.

Certain bacteria and algae can also capture light energy and use it to make food. For example, photosynthetic bacteria contain chlorophyll in tiny bodies called chromatophores. In chromatophores, compounds other than water are combined with carbon dioxide to form sugar. No oxygen is released.

Green plants convert carbon dioxide and water into food and oxygen. Plants and animals, in turn, "burn" the food by combining it with oxygen to release energy for growth and other activities of life. This process, which is called respiration, is the reverse of photosynthesis. Oxygen is used up and carbon dioxide and water are given off. Plants then use the carbon dioxide and water to produce more food and oxygen. The cycle of photosynthesis and respiration maintains the earth's natural balance of carbon dioxide and oxygen.