Page 11 - Science Class 07

Here ‘sym’ means together and 'bios' means plants. They trap and digest the insects. Pitcher
life. plant is the example of an insec vorous plant.

Lichen is the most common example of In pitcher plant, the leaf is modified to form a
symbio c nutri on. Here, algae and fungi live pitcher like structure. The bright colour of the
with close associa on with each other for pitcher makes it very a rac ve to insects.
nourishment. Algae is an autotroph and Inside the pitcher; there are several hair-like
manufactures food for itself as well as for the structures. These hair direct the trapped
fungi. On the other hand, fungi being insects downwards. When an insect sits on the
saprophyte provides water and minerals, and pitcher of the plant, the lid closes and the

shelter to algae. In this way, both are insect gets trapped inside the pitcher. The
benefi ed. insect is then digested by the enzymes secreted
by the cells of the plants.

Sundew, venus flytrap and bladder wort are
some other examples of insec vorous plants.
Causes of Ea ng of Insects by Plants

The soil of marshy land is deficient in nitrogen.
Plants living in marshy areas do not get
Lichen nitrogen from the soil. Their nitrogen need is
Rizobium bacteria present in the root nodules fulfilled by sucking the juice of insects. Venus
of legumes also exhibit symbio c rela onship. flytrap, utricularia, drosera and rafflesia are the
other examples of insec vorous plants.

1. What is heterotrophic mode of nutri on?
2. Give any two examples of saprophy c
organisms.
Rhizobium Bacteria 3. Why is cuscuta called a parasite?

INSECTIVOROUS NUTRITION 4. How saprophy c nutri on is different
Insec vorous is made up of two words insects from symbio c nutri on?
5. Give examples of any three insec vorous
and vorare means to eat. Some plants eat
plants.
insects. Such plants are called insec vorous

Nutrition : Process by which food is taken in and used by an organism
Autotrophs : Organisms that make food on their own, e.g., plants
Heterotrophs : Organisms that obtain food from plants or other animals

Photosynthesis : The process of making food by green plants
Stomata : Small pores present on the leaves for taking and releasing air
Chlorophyll : Green pigments present in leaves which trap sunlight

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