Prepared by Stephin.S

Natural scienceKUCTE

Kumarapuram

Nutrition in different lower animals like

Nutrition in Amoeba

Nutrition in Hydra

Nutrition in Planaria

Nutrition also called nourishment or aliment is the provision, to cells andorganisms, of the materials necessary (in the form of food) to support life.

Many common health problems can be prevented or alleviated with a healthy diet.

Nutrition: The process of intake of food and

its conversion into living protoplasm in cells.

• Autotrophs- Organisms which can prepare

their food

• Heterotrophs- Organism which cannot prepare

their own food due to lack of chlorophyll.

It is the nutrition obtained by digesting organic compounds.

Animals, fungi, many prokaryotes and protoctists are unable to synthesize organic compounds to use as food, They are called heterotrophs

Types of Heterotrophic Nutrition

Holozoic nutrition

Complex food is taken into a specialist digestive

system and broken down into small pieces to be

absorbed.

Saprotrophitic nutrition

Organisms feed on dead organic remains of

other organisms.

Parasitism

Organisms obtain food from other living

organisms (the host), with the host receiving

no benefit from the parasite.

Mutualism

A symbiotic relationship between organisms,

with each contributing and benefiting from

each other.

Holozoic nutrition (Gr. holo, whole + zoikos, of animals) is a method of nutrition that involves the ingestion of liquid or solid organic material, digestion, absorption and assimilation of it to utilize it.

This method suggests phagocytosis where the cell membrane completely surrounds the food particle(engulfing of food material)

Ingestion

Digestion

Absorption

Assimilation

Egestion

Unicellular

Freshwater organism

Microphagus Feeder

Intracellular digestion

Its diet includes bacteria, microscopic plants like the diatoms,

minute algae, microscopic animals like other protozoa, nematodes

and even dead organic matter.

Amoeba does not have any specialized structure or organ for the

process of nutrition.

It takes place through the general body surface with the help of

pseudopodia

Amoeba

Structure of AmoebaThe amoeba belongs to the kingdom Protista

. The name amoeba comes from the greek word amoibe, which means

change.

The amoeba is a single celled microscopic organism (about 0.3 mm across).

It has cytoplasm, nucleus, cell membrane and a variety of inclusions in the

cytoplasm and exhibits all the essential functions of any living organism.

They are found in fresh water (like puddle and ponds), salty water,

wet soil and in animals.

Structure of Amoeba (cont…)

Cell membrane: The cell membrane is flexible and porous. It allows the amoeba to

change shape.

Cytoplasm: Cytoplasm is the living substance which contains all the chemical

reactions necessary for life.

.Nucleus: A large, disk-shaped nucleus found in the cell.

Contractile Vacuole: The contractile vacuole removes excess water to the outside

from time to time (osmoregulation).

Food Vacuole: Microscopic organisms are digested and then exits through a structure

called a food vacuole.

Digestive Vacuole: This is a cavity responsible for digestion in the amoeba.

Pseudopodium: Pseudopodium means ‘false foot’. The amoeba move by stretching

its cytoplasm into finger like extensions called pseudopodia

Nutrition in amoeba is holozoic.

Solid food particles are ingested which are then acted upon by enzymes

and digested.

Lysosomes attached to food vacuole

Lysosomes secrete enzymes like proteases, amylases and lipases

in food vacuole

Food vacuole decreases in size due to water loss

It increases acidity and PH becomes 5.6 and Then 7.3

Fine canals produced from digestive vacuole

Absorption of food takes place by micropinocytosis

Food is circulated throughout the cytoplasm by cyclosis.

PROCESS OF DIGESTION IN AMOEBA

Hydra

Multicellular

Diploblastic

Belongs to phylum Cnidarians'

Macrophagus feeder

Aquatic animal

At the anterior end mouth surrounded with tentacles which are used to

capture the pray

In tentacles special cells Nematocysts are present

Nematocysts contains poison which paralyze the pray.

Structure of Hydra

The mouth of hydra opens into a cavity called gastrocoel or

enteron.

The endoderm contains two types of cells, glandular and

flagellated.

Glandular cells secrete proteolytic enzymes , which are helpful in

digestion

The flagellated cells and contraction of body wall also help in

digestion

Hydra cannot digest starch.

The digestion is extracellular as well as intracellular

Flatworm

Belongs to phylum Platyhelminthes

Carnivores

Tube like alimentary canal is present

It has three parts: mouth, pharynx and intestine

When it takes food from outside, the pharynx comes out from the

mouth

Internally the pharynx opens into the intestine, which divides into

three branches

Structure of Planaria

The branching system is formed for digestion, absorption and

distribution of food

This system is called Gastro-Vascular system

The food is taken in through the mouth which comes into the

pharynx and then intestine

The enzyme act upon the food in the intestine

The digested food is absorbed by the branches of intestine, which is

distributed throughout the body by diffusion

Digestion is both intracellular and extracellular

Digestion in Planaria

conclusion The process of intake of food and its conversion into

living protoplasm in cells

Most of the lower animal that possess hetrotrophic

nutrition

Amoeba, Hydra ,and Planaria each one possess

different mode of nutrition

Quiz paper Q1: The nutrition which is obtained by digesting organic compounds is called as

Holozoic

Heterotrophic

Autographs

Saprotrophs

Q2: There are five steps of holozoic nutrition: Ingestion, digestion, absorption , assimilation and egestion.

True

False

Q3: The digestion in hydra is _______________ as well as ___

Q4: In tentacles special cells called _______________ are present

Q5: The process of ingestion takes place by _______________ in amoeba.

References

SCERT Text Book of Standard VIII

www.Google.com

www.Youtube.com