Concise Biology Notes

Biology studies life forms and living processes.
Early humans recognized the difference between living and non-living things.
Systematic description of life forms led to identification, nomenclature, and classification systems.
Recognition of similarities among organisms revealed relationships and led to biodiversity conservation efforts.

Ernst Mayr (1904-2004): Harvard evolutionary biologist, "The Darwin of the 20th century".
Pioneered the concept of species diversity and the biological species definition.
Awarded the Balzan Prize (1983), the International Prize for Biology (1994), and the Crafoord Prize (1999).

The living world exhibits a wide range of types and habitats.
The number of known and described species ranges from 1.7-1.8 million, referred to as biodiversity.

Nomenclature: Standardizing naming of organisms.
Identification: Correctly describing and knowing the organism that the name is attached to.
International Code for Botanical Nomenclature (ICBN): Used for plants.
International Code of Zoological Nomenclature (ICZN): Used for animals.
Binomial Nomenclature: Two-component naming system (Generic name and specific epithet) given by Carolus Linnaeus.
- Example: Mangifera indica (Mango) where Mangifera is the genus and indica is the specific epithet.
Rules for nomenclature:
- Biological names are in Latin and written in italics.
- Genus starts with a capital letter, the specific epithet with a small letter.
- When handwritten, underline separately; when printed, use italics.
- Author's name appears in abbreviated form after the specific epithet (e.g., Mangifera indica Linn.).
Classification: Grouping organisms into categories based on observable characters.
Taxa: Scientific term for these categories (e.g., Dogs, Cats, Mammals, Wheat).
Taxonomy: Process of classifying organisms based on external and internal structure, cell structure, development, and ecological information.

Systematics: Study of relationships among organisms.
- Derived from the Latin word 'systema,' meaning systematic arrangement.
- Includes identification, nomenclature, and classification, considering evolutionary relationships.

Classification involves a hierarchy of steps representing ranks or categories.
Taxonomic category: Part of the taxonomic arrangement.
Taxonomic hierarchy: All categories together.
Taxon: Unit of classification representing a rank.
Common categories: kingdom, phylum/division, class, order, family, genus, and species.

Species: Group of individual organisms with fundamental similarities.
- Examples: Mangifera indica, Solanum tuberosum, Panthera leo.
Genus: Group of related species with more common characters.
- Examples: Solanum (potato, brinjal), Panthera (lion, leopard, tiger).
Family: Group of related genera with fewer similarities than genus and species.
- Examples: Solanaceae (Solanum, Petunia, Datura), Felidae (Panthera, Felis), Canidae (dogs).
Order: Assemblage of families with a few similar characters.
- Examples: Polymoniales (Convolvulaceae, Solanaceae), Carnivora (Felidae, Canidae).
Class: Includes related orders.
- Example: Mammalia (Primata, Carnivora).
Phylum/Division: Classes with similar characters.
- Example: Chordata (fishes, amphibians, reptiles, birds, mammals).
Kingdom: Highest category; Animalia (all animals), Plantae (all plants).

Arrangement: Species to Kingdom in ascending order.
As you go higher, common characteristics decrease.
Lower taxa share more characteristics; higher categories increase difficulty in determining relationships.