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Biology Notes 6.1
Unit 6
Modes of nutrition
I. What is nutrition?
i. A process by which organisms obtain nutrient for
maintaining life.
ii. Nutrition and food materials for:
- growth and body repair
- release of energy
- maintaining different life process
iii. Two modes of nutrition:
1. Autotrophic nutrition*
2. Heterotrophic nutrition*
a. Holozoic nutrition*
- Carnivorous (eats meats)
- herbivorous (eats plants)
- omnivorous (eats both plants and meats)
b. Saprophytic nutrition*
c. Parasitic nutrition*
iv. These different modes of nutrition can be summarized in
the chart below. (P.101)
Nutrition
Autotrophic
Holozoic
Herbivore
Carnivore
Heterotrophic
Saprophytic
Parasitic
Omnivore
* Organ compound
- carbon, hydrogen, oxygen to form a complex molecules
e.g. 1. Carbohydrate - glucose (C6H12O6)
2. Protein
3. Lipid - fats
- oil
- wax
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(1)
Autotrophic nutrition
- Photosynthesis
sunlight
Water + C02
carbohydrate + O2 + Water
chlorophyll
(2) Heterotrophic nutrition
e.g. all animals, fungi and most bacteria
- they cannot synthesize organic food themselves
- they depend on autotrophs for obtaining organic substances
(A) Holozoic nutrition
- found in most animals in which solid or liquid food is
ingested
- This nutrient has 3 types
(i) Herbivores
- animal feed on plant only
e.g. goat, cow, rabbit, rhinoceros*
(ii) Carnivores
- animal feed on animal only
e.g. tiger, lion, snake
(iii) Omnivore
- animal feed on both plants & animals
e.g. man, pig, mouse
(B) Saprophytic nutrition
- organisms obtain food from dead organic matter
e.g. bread mould
- without chlorophyll
- depends on bread for food
- consists of hyphae → form mycelium
- some hyphae penetrate into bread
↓
produce digestive enzyme
(extra - cellular digestion)
- absorb digested food by diffusion
- act as decomposer in the ecosystem
* Autotrophic nutrition 自養營養
* Parasitic nutrition 寄生營養
* Heterotrophic nutrition 異養營養
* rhinoceros 犀牛
* Holozoic nutrition 動作式營養
* Saprophytic nutrition 腐生營養
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(C)
Parasitic nutrition
- a type of nutrition which an organism obtain benefits
from and at the same time causes harm to its partner
- the first organisms is called a parasite which the
partner is called a host
- types of parasites
i. tapeworm - parasite which has within the body of
its host is called endoparasite.
Problem to parasitic
Special features
Adaptations
mode of life
a. Attachment to
the host
Head with hooks &
Attach it firmly to the
suckers
intestine wall of the host to
prevent it to be removed
away during peristalsis
b. Fitting itself
Elongated body
Fit the course of the intestine
i. Live in small intestine
i. Bathe in a medium of
inside the host
c. Obtaining
nutrients
digested food which is
efficiently
for immediately use
ii. Elongated flattened
ii. increase the surface area to
body
absorb the digested food by
diffusion & active transport
through the body surface.
iii. Digestive system is
iii. No need to digested food.
denatured
d. Storage of
Anaerobic respiration
oxygen
e. Host reaction
Produce energy inside the small
intestine
Cover segment with mucus
Protect it against the digestive
juices of the host
f. Continuation of
generation
i. The adult is a
i. Avoids the trouble of finding
hermaphrodite (bisexual) a
mate inside the heat
ii. Each segment produces
a large number of eggs
ii. increase the chance to infect
the secondary host
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