Define family.

Define family.

Source: NCERT Class 11 Biology Chapter 1 – The Living World Question 9 (iii)

A family is a level of classification in the Linnaean system of taxonomy. It is used to group organisms that share many characteristics but are less closely related than those in the same genus. The family level is one step below the order level and above the genus level in the classification hierarchy.

For example, within the animal kingdom, the family Canidae includes dogs, wolves, foxes, and other canines which share certain characteristics such as a similar skull shape and dentition. Similarly, within the plant kingdom, the family Asteraceae includes daisies, sunflowers, and other plants which share certain characteristics such as flower head composed of many small flowers.

It is important to note that, like other levels of classification, the characteristics used to group organisms into families can vary widely depending on the group of organisms, and the definition and content of a family can change as new information becomes available. Also, different systems of classification may use different criteria for grouping organisms into families, but the goal is to group organisms that share many characteristics but are less closely related than those in the same genus.

In summary, a family is a level of classification in the Linnaean system of taxonomy, used to group organisms that share many characteristics but are less closely related than those in the same genus. This level of classification is widely used across different branches of the tree of life, like animals, plants, fungi, algae, and microorganisms, and the characteristics used to classify can vary widely depending on the group of organisms. It is an important part of the classification hierarchy that allows us to organize and communicate information about different groups of organisms, and make predictions about their characteristics and behavior.

In addition to the traditional Linnaean system, there are also other systems of classification that use the concept of family, such as the Phylogenetic system, which is based on evolutionary relationships rather than morphological features. In Phylogenetics, families are a group of genera that share a common ancestor and have many similarities in their characteristics, but are not as closely related as those within the same genus.

It's also worth noting that the number and content of families can change as new discoveries and research updates the classification system. For example, new molecular and genetic techniques are providing new information about the relationships between different groups of organisms, leading to changes in the classification of many families. And also sometimes taxonomist may split or join families based on the new data.

Furthermore, the classification of organisms into different families is based on a combination of various characteristics, not only morphological but also molecular and genetic characteristics, that help to infer evolutionary relationships between different groups of organisms. It is also important to note that the classification of organisms is a continuous process, and new information and techniques can lead to changes in classification, new discoveries can lead to new families being described or the redefining of existing families.

Other questions from NCERT Class 11 Biology Chapter 1 The Living World Solutions:

Question 1: Why are living organisms classified?

Question 2: Why are the classification systems changing every now and then?

Question 3: What different criteria would you choose to classify people that you meet often?

Question 4: What do we learn from the identification of individuals and populations?

Question 5: Given below is the scientific name of Mango. Identify the correctly written name. Mangifera Indica or Mangifera indica

Question 6: Define a taxon. Give some examples of taxa at different hierarchical levels.

Question 7: Can you identify the correct sequence of taxonomical categories? (a) Species Order Phylum Kingdom (b) Genus Species Order Kingdom (c) Species Genus Order Phylum

Question 8: Try to collect all the currently accepted meanings for the word ‘species’. Discuss with your teacher the meaning of species in the case of higher plants and animals on the one hand and bacteria on the other hand.

Question 9:  Define and understand the following terms. (i) Phylum (ii) Class (iii) Family (iv) Order (v) Genus

Question 10: How is a key helpful in the identification and classification of an organism?

Question 11: Illustrate the taxonomical hierarchy with suitable examples of a plant and an animal.