Biological Foundations: From Bioelements to Biodiversity
Essential Bioelements and Biomolecules
Primary Bioelements: Carbon (C), Oxygen (O), Hydrogen (H), Nitrogen (N), Phosphorus (P), and Sulfur (S). These are highly abundant, making up 98% of living matter. Carbon is the most characteristic, as it forms the long chains that serve as the basic structure of living things.
Secondary Bioelements: Calcium (Ca), Sodium (Na), Potassium (K), Magnesium (Mg), and Chlorine (Cl).
Trace Elements: Also known as vestigial elements, these make up less than 0.1% of the organism (e.g., Iron/Fe).
Biomolecules and Their Functions
- Water: The amount depends on species, age, and tissue type. It serves as the environment for chemical reactions, a vital means of transport, and a chemical reagent.
- Minerals: These can be soluble (dissolved and ionized) or insoluble (precipitated). Soluble minerals regulate osmotic processes, participate in chemical reactions, and act as pH buffers. Insoluble salts form skeletal structures.
Cell Theory and Biological Characteristics
The cell is the morphological, structural, and functional unit of life; it is the smallest part of an organism capable of performing vital functions. Cell Theory was enunciated by Schleiden and Schwann for plants and animals, stating that all organisms are composed of one or more cells. Virchow later established that all cells arise from pre-existing cells (vital, anatomical, physiological, and genetic unity).
Key Cell Characteristics
- Semipermeable membrane and cytoplasm consisting of biomolecules in colloidal suspension where life reactions occur.
- Presence of DNA and RNA.
- Eukaryotes possess organelles and a nuclear membrane.
- Law of Constant Cell Volume: While dimensions vary between types, volume remains relatively constant within the same cell type.
Taxonomy and the Binomial System
Taxonomy is the scientific discipline responsible for classifying and naming living things. It dates back to the 18th century with Linnaeus, who replaced polynomial names with the binomial system (generic and specific names), which proved more effective.
Taxonomic Hierarchy
The hierarchy of classification follows this order: Kingdom, Phylum (or Division), Class, Order, Family, Genus, and Species.
Classification of the Five Kingdoms
- Kingdom Monera: Prokaryotic organisms.
- Kingdom Protoctista: Includes Phylum Protozoa (Sarcodina, Flagellates, Ciliates, and Sporozoa), Phylum Algae (Chlorophyta, Phaeophyta, and Rhodophyta), and Slime Molds.
- Kingdom Fungi: Divisions include Zygomycetes, Deuteromycetes, Ascomycetes, and Basidiomycetes.
- Kingdom Plantae: Divided into Bryophytes and Tracheophytes (including Pteridophytes and Spermatophytes).
- Kingdom Animalia: Includes Phyla such as Porifera, Cnidarians, Platyhelminthes, Nematodes, Annelids, Mollusks, Arthropods, Echinoderms, and Chordates.
The Importance of Biodiversity
Biodiversity provides essential benefits across four main categories: ecological, economic, ethical, and aesthetic.