Delhi Public School

B.S.City

BIOLOGY Date:10.04.2020

Class 7 FOOD (continued….)

OTHER MODES OF NUTRITION Green plants can make their own food from carbon dioxide and water in the presence of sunlight and chlorophyll. Plants which do not contain chlorophyll depend on other living organisms for their food.Thus, the plants which do not contain chlorophyll are heterotrophs and mode of nutrition is heterotrophic.

Nutrition in Plants that do not contain Chlorophyll Many plants do not contain any chlorophyll. Hence they are unable to prepare their food by themselves. Therefore, they rely on other plants and animals for their food. Various types of such nutrition are: 1. Saprophytic Nutrition - Some organisms survive on decaying food and organisms. This mode of nutrition is called saprotrophic nutrition and the organisms that survive because of the saprotrophic nutrition are called Saprophytes . How do saprophytes obtain their nutrition ? • The saprophytes secrete digestive juices on the decaying and dead matter. • These juices convert the matter into a solution. • The saprophytes that absorb the nutrients from the solution. • For Example, Fungi (yeast and mushrooms) are a saprophytes that can be found on stale food and pickles which are exposed to the hot and humid environment. Bacteria like Lactobacillus, Acetobacter is saprophytic as they derive their food from dead and decaying organic matter.

Fungi growing on Bread 2. Parasitic Nutrition - Some plants live on another plant for their nutrition. These are called parasites. The plants on which these parasitic plants survive are called the host. For Example, Cuscuta is a parasitic plant.

The parasitic plants may be total parasites or partial parasites. The plants which depend wholly on the host plants for their food are called totally parasitic plants . Eg- Cuscuta, Apodanthes, are totally parasitic plants.

Yellow colour Cuscuta plant growing over green plants

The plants which make a part of their food themselves by photosynthesis but derive other components such as water and minerals, etc ,from the host plant are called partial parasitic plants . Plant like Mistletoe is partially parasitic because they make their food themselves but get water and minerals from the host plants.

WORKSHEET

Q1.Which type of nutrition is shown by non-green plants and why?

Q2.Why is mode of nutrition in fungi is said to be as saprophytic?

Q3.State one point of difference between totally parasitic and partial parasitic plants with an example.

Q4.How does plant like Cuscuta derive its nutrition?