Biology Chapter 1: The Living World

Study Notes

The living world comprises an amazing diversity of living organisms, with diverse habitats, and ecological conflicts and cooperation among populations.

Biology is the science of life forms and living processes.
Early man could distinguish between inanimate matter and living organisms.
Classification of living organisms is necessary to understand the diversity of life.
The process of classification involves identification, nomenclature, and taxonomy.

Ernst Mayr (1904-2004) was an evolutionary biologist and ornithologist who made significant contributions to the field of biology.
He is considered the "Darwin of the 20th century" and was awarded the Balzan Prize, International Prize for Biology, and the Crafoord Prize.

There are approximately 1.7-1.8 million known species of living organisms on Earth.
New species are continuously being identified, and classification is necessary to understand the diversity of life.

Nomenclature is the process of assigning scientific names to living organisms.
The scientific name of an organism is a unique combination of generic and specific epithets.
Binomial nomenclature is the system of providing a scientific name with two components, a generic name and a specific epithet.
This system was developed by Carolus Linnaeus.

Taxonomic categories are hierarchical and include Kingdom, Phylum, Class, Order, Family, Genus, and Species.
Each category is a unit of classification and represents a rank or level of organization.
The categories become more specific as you move from Kingdom to Species.

Species: a group of individual organisms with fundamental similarities.
Genus: a group of related species with more characteristics in common.
Family: a group of related genera with still fewer similarities.
Order: a group of related families with fewer similarities.
Class: a group of related orders.
Phylum: a group of related classes (in animals) or divisions (in plants).
Kingdom: the highest category, comprising all animals (Kingdom Animalia) or plants (Kingdom Plantae).

Taxonomic categories help in identifying and understanding the relationships among different organisms.
They provide a framework for classification and understanding the diversity of life.
They help in recognizing the similarities and differences among organisms.

Figure 1.1 shows the hierarchical arrangement of taxonomic categories from Species to Kingdom.
Table 1.1 provides examples of common organisms and their taxonomic categories.### Taxonomic Categories
Organisms can be classified into different categories, including Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species.
The taxonomic categories are hierarchical, with each category becoming more specific.

Living organisms exhibit a wide range of characteristics, including size, color, habitat, physiological features, and morphological features.
These characteristics are used to identify and classify organisms.

Taxonomy is the branch of biology that deals with the identification, naming, and classification of organisms.
Taxonomic studies are useful in agriculture, forestry, industry, and for understanding bio-resources and their diversity.

The binomial system of nomenclature is used to assign scientific names to organisms.
Each scientific name consists of two words: a genus name and a species name.
The binomial system is universally accepted and follows international codes.

The taxonomic hierarchy is a system of classification that consists of multiple categories.
Each category represents a level of classification, with each level becoming more specific.
The categories include Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species.

Human (Homo sapiens): Kingdom - Animalia, Phylum - Chordata, Class - Mammalia, Order - Primata, Family - Hominidae, Genus - Homo
Housefly (Musca domestica): Kingdom - Animalia, Phylum - Arthropoda, Class - Insecta, Order - Diptera, Family - Muscidae, Genus - Musca
Mango (Mangifera indica): Kingdom - Plantae, Phylum - Angiospermae, Class - Dicotyledonae, Order - Sapindales, Family - Anacardiaceae, Genus - Mangifera
Wheat (Triticum aestivum): Kingdom - Plantae, Phylum - Angiospermae, Class - Monocotyledonae, Order - Poales, Family - Poaceae, Genus - Triticum