Defences Against Diseases
The body has three main lines of defence against disease. These involve mechanical barriers, chemical barriers and cells. Mechanical barriers Although many bacteria live on the surface of the skin, the outer layer of the epidermis seems to act as a barrier that stops them getting into the body. But if the skin is cut or damaged, the bacteria may get into the deeper tissues and cause infection. Hairs in the nose help to filter out bacteria that are breathed in. However, if the air is breathed in through the mouth, this defence is by-passed. Chemical barriers The acid conditions in the stomach destroy most of the bacteria that may…
True Or False On Carbohydrates
Types of Classification System
Biological classification is the scientific procedure of arranging organisms into groups on the basis of their similarities and dissimilarities and placing the groups in a hierarchy of categories like species, genus, family, etc
The living world and Taxonomy Flashcards
Ecosystem – Structure and Function
https://youtu.be/RlWj__29Uew The term ‘ecosystem’ was proposed by a British ecologist A.G. Tansley (1953). It represents the basic fundamental, functional unit of ecology which comprises of the biotic community together with its abiotic (non-living) environment. Ecosystem is the functional unit of nature where living organisms interact with each other and with their environment. Ecosystems can be recognized as self-regulating and self-sustaining units of landscapes that may be terrestrial or aquatic. Forests, grasslands and deserts are examples of terrestrial ecosystems. The aquatic ecosystems can be either freshwater (ponds, lakes, streams) or saltwater (marine estuaries) type. Ecosystem may be natural (forest, sea) if developed under natural conditions or artificial (garden, aquarium, agriculture) if…
