TYPE OF NUTRITION

OBJECTIVE: To classify organisms according to their type of nutrition

PROBLEM STATEMENT: Do the organisms belong to the same type of

nutrition?

MATERIALS: A4 papers, reference books, textbook, Internet

APPARATUS: Computer, printer

TECHNIQUE: Collecting, sorting, classifying and copying the source of information according to the type of nutrition

PROCEDURE: 1. The types of nutrition are stated.2. Autotrophic nutrition is explained.3. Heterotrophic nutrition is explained.4. Organisms are classified according to types of nutrition.

WHAT IS NUTRITION?

All living organisms need food but unlike green plants, which make their own food, humans and all animals need to obtain food from other living organisms.

Nutritional science studies how the body breaks food down (catabolism) and repairs and creates cells and tissue (anabolism) - catabolism and anabolism = metabolism. Nutritional science also examines how the body responds to food. In other words, "nutritional science investigates the metabolic and physiological responses of the body to diet".

As molecular biology, biochemistry and genetics advance, nutrition has become more focused on the steps of biochemical sequences through which substances inside us and other living organisms are transformed from one form to another - metabolism and metabolic pathways.

Nutrition also focuses on how diseases, conditions and problems can be prevented or lessened with a healthy diet.

Nutrition also involves identifying how certain diseases, conditions or problems may be caused by dietary factors, such as poor diet (malnutrition), food allergies and metabolic diseases.

Living organisms can be divided into two main groups based on their nutritional habits which are:

i) Autotrophsii) Heterotrophs

AUTOTROPHSThe word autotrophs come from the Latin words autos which means

self and trophos which means feed. Therefore, autotrophs mean self-feeder. These are organisms which practice autotrophic nutrition. They are capable of synthesizing their own organic substances from inorganic compounds.

Autotrophs produce their own sugars, lipids, and amino acids using carbon dioxide as a source of carbon, and ammonia or nitrates as a source of nitrogen. Organisms that use light for the energy to synthesize organic compounds are called photosynthetic autotrophs; organisms that oxidize such compounds as hydrogen sulfide (H2S) to obtain energy are called chemosynthetic autotrophs, or chemotrophs.

Photosynthetic autotrophs include the green plants, certain algae, and the pigmented sulfur bacteria. Chemotrophs include the iron bacteria, the nitrifying bacteria, and the nonpigmented sulfur bacteria.

Photosynthetic Autotrophs/Photosynthesis

Photosynthesis (from the Greek word photo, meaning "light," and synthesis, from the Greek work syntithenai, which means "to put together") is the process by which plants use energy derived from light in order to make food molecules from carbon dioxide and water. Photosynthesis is a dual-staged process with multiple components. Light reactions or light-dependent reactions compose the first steps of photosynthesis.

During the light reactions, light energy derived from sunlight is converted to chemical energy. Oxygen (O2) is produced as a waste product of this process. The steps of the second stage are the carbon-fixation reactions known as the Calvin cycle. The Calvin cycle is a series of reactions that assemble sugar molecules from carbon dioxide (CO2) and the energy-containing products of the light reactions. Carbon fixation is the conversion of carbon dioxide (CO2) into organic compounds.

EXAMPLES OF ORGANISMS WHICH USE PHOTOSYNTHESIS

Magnolia plant Algae

Banana tree

Paddy plant

Pink Bougainvillea

Chemosynthesis

Chemosynthesis is a process in which carbohydrates are manufactured from carbon dioxide and water using chemical nutrients as the energy source, rather than the sunlight used for energy in photosynthesis. Most life on earth is fueled directly or indirectly by sunlight. There are, however, certain groups of bacteria, referred to as chemosynthetic autotrophs, that are fueled not by the sun but by the oxidation of simple inorganic chemicals, such as sulfates or ammonia. Chemosynthetic autotrophs are a necessary part of the nitrogen cycle. Some groups of these bacteria are well suited to conditions that would have existed on the earth billions of years ago, leading some to postulate that these are living representatives of the earliest life on earth. This view has been supported by the discovery of small ecosystems that thrive in the hot (350°C/660°F) water found around hydrothermal vents on the ocean floor. In these ecosystems, the primary producers in the food web are bacteria whose life functions are fueled by inorganic chemicals that seep up from the earth's crust.

EXAMPLES OF ORGANISMS WHICH USE CHEMOSYNTHESIS

Giant tube worms (Rifta sp.) Eubacteria

HETEROTROPHS

A heterotroph (heteros: other) is an organism that uses organic carbon for growth by consuming other organisms. This contrasts with autotrophs, such as plants, which can directly use sources of energy such as light to produce organic substrates from carbon dioxide. Heterotrophs may practise holozoic nutrition, saprophytism or parasitism.

Holozoic nutrition

Holozoic nutrition (Greek: holo = whole, zoikos = of animals) is a method of nutrition that involves the ingestion of liquid or solid organic material. This method suggests phagocytosis where the cell membrane completely surrounds a food particle.

Most of the free living animals including humans exhibit this type of nutrition. In this mode of nutrition, the food may be a small bacterium, a plant or an animal. Here, the food is first taken into the body through an opening called a mouth (ingestion), then it is converted into a simple and soluble form by various enzymes (digestion); simplified products thus formed are then absorbed (absorption); the conversion of nutrient into the fluid or solid substance of the body (Assimilation); and finally the undigested part of food is removed from the body (egestion). This type of nutrition occurs mainly in single celled organisms such as Amoeba.

EXAMPLES OF ANIMALS THAT USE HOLOZOIC NUTRITION

Venus fly trap Tiger Amoeba

Saprophytism

In this method of nutrition, organisms called saprophytes obtain nutrients by consuming decomposing organic matter. By doing so, they contribute to decomposition and the nutrient cycles.

Saprophytes are an important aspect of many ecosystems. They can live on any soil with an organic component, and even live in marine ecosystems where they are termed interchangeably with bottom feeders.

Typical saprophytes animals include millipedes, woodlice, dung flies, slugs, many terrestrial worms, sea stars, fiddler crabs, and some sedentary polychaetes such as amphitrites (Amphitritinae, worms of the family terebellidae) and other terebellids.

Many species of bacteria, fungi and protists, unable to ingest discrete lumps of matter, instead live by absorbing and metabolising on a molecular scale. Scavengers are typically not thought to be detritivores, as they generally consume larger quantities of organic matter. Coprovores are also usually treated separately as they exhibit a slightly different feeding behaviour. The eating of wood, whether live or dead, is known as xylophagy. Animals feeding only on dead wood are called sapro-xylophagy/sapro-xylophagous.

EXAMPLES OF SAPROPHYTES

Fungi Earthworm

Fiddler crab Christmas tree

worms

(Spirobranchus giganteus)

Parasitism

Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the host. Traditionally parasite referred to organisms with lifestages that went beyond one host (e.g. Taenia solium), which are now called macroparasites (typically protozoa and helminths). Parasites also include microparasites, which are typically smaller, such as viruses and bacteria, can be directly transmitted between hosts of one species. Parasites are generally much smaller than their host, show a high degree of specialization for their mode of life, and reproduce at a faster rate than their hosts. Classic examples of parasitism include interactions between vertebrate hosts and diverse animals such as tapeworms, flukes, the Plasmodium species, and fleas. Parasitism is differentiated from parasitoidism, a relationship in which the

host is always killed by the parasite such as moths, butterflies, ants, flies and others.

The harm and benefit in parasitic interactions concern the biological fitness of the organisms involved. Parasites reduce host fitness in many ways, ranging from general or specialized pathology (such as castration), impairment of secondary sex characteristics, to the modification of host behaviour. Parasites increase their fitness by exploiting hosts for food, habitat and dispersal.

Flea Mosquito

REFERENCES Gan Wan Yeat, Manoharan a/l Subramanian, Azmah binti Rajion;

2005; Biology Form 4 Textbook; Petaling Jaya; Bakaprep Sdn Bhd.

Mah Chee Wai, Dr Tina Lim Swee Kim; 2010; Nexus Pro SPM 4-5: Biology; Petaling Jaya; Sasbadi Sdn Bhd.

www.answers.com en.wikipedia.org

SEKOLAH MENENGAH KEBANGSAAN DATO BENTARA DALAM

TYPE OF NUTRITION

NAME: FOONG CHIN YEN

CLASS: 4 NEWTON

IC NUMBER: 940427-01-5069

TEACHER’S NAME: EN. IBRAHIM BIN TAIGO