Complete Concept Guide (100% Curriculum Coverage)
1. Defining Characteristics of Life
While growth and reproduction occur in living systems, non-living things (like growing sand dunes) can accumulate mass. Therefore, Metabolism (the sum total of all chemical reactions occurring in the body) and Consciousness / Cellular Organization are the true defining properties of living organisms.
2. Binomial Nomenclature (Linnaeus)
Carolus Linnaeus established universal binomial rules:
• Each scientific name consists of two Latin words: Genus (capitalized) and Specific epithet (lowercase).
• Printed in italics; underlined separately when handwritten (e.g. Homo sapiens, Mangifera indica for mango).
• Standardized by ICBN (plants) and ICZN (animals).
3. Taxonomic Hierarchy
Species are grouped into ascending categorical ranks: $$\mathbf{\text{Species} \longrightarrow \text{Genus} \longrightarrow \text{Family} \longrightarrow \text{Order} \longrightarrow \text{Class} \longrightarrow \text{Phylum/Division} \longrightarrow \text{Kingdom}}$$ As we move from species to kingdom, the number of common shared characteristics decreases.
Check Your Understanding (Diagnostic Practice Questions)
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1
Why are growth and reproduction not considered defining characteristics of living organisms?
Reveal Answer & Explanation
Answer: Because non-living objects (like mountains and crystals) also grow by external accumulation of matter, and many living organisms (like sterile worker bees, mules, and infertile human couples) cannot reproduce.
Non-living things grow externally; sterile organisms do not reproduce.
2
Write the scientific name of mango and state the rules of binomial nomenclature.
Reveal Answer & Explanation
Answer: Mangifera indica. Rules: (1) Names are derived from Latin and written in italics, (2) The first word is the Genus starting with a capital letter, (3) The second word is the specific epithet starting with a lowercase letter, (4) Hand-written names must be underlined separately.
Mangifera indica; Latin, Genus capitalized, species lowercase.
3
Arrange the following taxonomic categories in ascending order: Family, Species, Class, Order, Genus, Kingdom, Phylum.
Reveal Answer & Explanation
Answer: Species → Genus → Family → Order → Class → Phylum → Kingdom.
Species to Kingdom ascending order.
4
What is Metabolism and why is it a defining feature of life?
Reveal Answer & Explanation
Answer: Metabolism is the sum total of all chemical transformations occurring inside an organism. No non-living object exhibits metabolism; it occurs exclusively in living cellular systems.
Sum of all biochemical reactions in cellular life.
5
What is the difference between Taxonomy and Systematics?
Reveal Answer & Explanation
Answer: Taxonomy deals with the identification, nomenclature, and classification of organisms; Systematics encompasses taxonomy along with the comprehensive study of evolutionary relationships among organisms.
Taxonomy is classification; systematics includes evolutionary history.
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