Biosphere and Biological Classification

These flashcards cover the fundamental vocabulary of biological classification, including the domains of life, plant and animal kingdoms, and the principles of scientific nomenclature based on the lecture notes.

Life's Origin

It is believed that life originated on earth about $3.6$ billion years ago as unicellular organisms.

Species Diversity

There are approximately $8.7$ million species living on earth today.

Classification

The grouping of organisms into different levels based on their common characteristics.

Artificial Classification

A grouping method based on superficial features, such as grouping birds and insects together because they both have wings, which does not depict evolutionary relationships.

Natural Classification

A grouping method that explains natural and evolutionary relationships among different organisms and the same species.

Taxonomic Hierarchy

The ranking of categories from broadest to most specific: Domain, Kingdom, Phylum/Division, Class, Order, Family, Genus, and Species.

Domain Archaea

Prokaryotic organisms living in extreme environments, such as Methanogens and Halophiles, which are not sensitive to most antibiotics.

Domain Bacteria

The most abundant group of prokaryotes, including Bacteria and Cyanobacteria, which are sensitive to antibiotics and can be pathogenic.

Viruses

Entities that possess both living and non-living features, with their only living feature being multiplication within a host cell.

Domain Eukarya

Organisms with eukaryotic cellular organization, categorized into four kingdoms: Protista, Fungi, Plantae, and Animalia.

Kingdom Protista

Unicellular or multicellular eukaryotes without specialized tissues, such as Algae and Protozoans (e.g., Amoeba, Paramecium).

Kingdom Fungi

Eukaryotic organisms with chitinous cell walls that act as decomposers, and include species like Mushroom (Agaricus) and Yeast.

Gymnosperms

Naked seed plants whose seeds are not covered by a fruit, such as Cycas and Pinus.

Angiosperms

Covered seed plants where seeds are enclosed within a fruit, divided into monocots and dicots.

Monocotyledonae

Plants with a single cotyledon in the seed, unbranched stems, fibrous root systems, and parallel leaf venation (e.g., Coconut, Paddy).

Dicotyledonae

Plants with two cotyledons in the seed, branched stems, tap root systems, and reticulate leaf venation (e.g., Mango, Jak).

Kingdom Animalia

Multicellular heterotrophic organisms divided into Invertebrates and Vertebrates based on the presence of a vertebral column.

Diploblastic

Organisms having a multicellular body built of two germinal layers, such as those in Phylum Cnidaria.

Coelenteron

The central body cavity in Cnidaria that acts as the digestive tract.

Triploblastic

Organisms having a multicellular body made up of three germinal layers, such as Annelids and Mulluscs.

Annelida

The first organisms to evolve a body cavity called coelom

Phylum Arthropoda

The largest phylum in the animal kingdom, containing $75\%$ of all species, characterized by jointed limbs and a chitinous exoskeleton.

Phylum Echinodermata

Marine organisms with penta radial symmetry, a spiny body covering, and a water vascular system (e.g., Sea urchin, Sea cucumber).

Poikilothermic

Cold-blooded animals whose body temperature changes according to the environmental temperature, such as Pisces, Amphibia, and Reptilia.

Homeothermic

Warm-blooded animals that maintain a constant body temperature regardless of the environment, such as Aves and Mammalia.

Class Mammalia

Vertebrates characterized by skin covered with hair, the presence of mammary glands to produce milk, and a four-chambered heart.

Binomial Nomenclature

A two-part naming system introduced by Carolus Linnaeus, consisting of a Genus name (capitalized) and a species name (lowercase), both italicized or underlined.