The document discusses nutrition in various lower animals including amoeba, hydra, and planaria. It describes their structures, modes of nutrition, and digestive processes. Amoeba obtains nutrition through holozoic means, ingesting and digesting food intracellularly using food vacuoles. Hydra's mouth opens to a gastrocoel cavity containing glandular cells that secrete enzymes, aiding both extracellular and intracellular digestion. Planaria has a tube-like alimentary canal with a branching intestinal system for digestion, absorption, and distribution of food throughout its body.

1. Prepared by
Stephin.S
Natural science
KUCTE
Kumarapuram

3. Nutrition in different lower
animals like
Nutrition in Amoeba
Nutrition in Hydra
Nutrition in Planaria

4. 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.

5. 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.

6. 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

7. 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.

8. 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.

9.  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)

10. Ingestion
Digestion
Absorption
Assimilation
Egestion

11.  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

12. Amoeba

13. Structure of Amoeba
The 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.

14. 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

16.  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.

17. PROCESS OF DIGESTION IN AMOEBA

18. Hydra

19.  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.

20. Structure of Hydra

21.  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

23.  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

24. Structure of Planaria

25.  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

27. Digestion in Planaria

28. 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

29. 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.

30. References
SCERT Text Book of Standard VIII
www.Google.com
www.Youtube.com