Biological Taxonomy and Evolutionary Processes Explained

Biological Taxonomy and Classification

The classification of living beings is known as taxonomy. The hierarchical categories are: kingdom, phylum, class, order, family, genus, and species.

The Five Kingdoms

• Plants: Ferns, gymnosperms, mosses.
• Fungi: Mushrooms, molds, yeasts.
• Animals: Mammals, birds, amphibians, fish.
• Protoctists: Protozoa (ciliates, amoebae) and algae (brown, green, and red).
• Monera: Bacteria.

Species and Genetics

A species is a group of individuals with similar characteristics that breed among themselves to produce fertile offspring.

Factors Influencing Variation

• Inheritable: Changes in genetic information.
  • Mutations: Errors in the DNA instructions of cells.
  • Recombination of genes: Occurs during sexual reproduction, where genes from male and female gametes combine to produce offspring different from parents.
• Environmental: Changes due to exposure to different environments, which are not transmitted to offspring.

Speciation and Reproductive Isolation

Speciation is the process of forming new species from a common ancestor. Reproductive isolation identifies a group of individuals as a species based on their ability to reproduce and exchange genetic information.

• Physical or geographical: Usually the first barrier to occur.
• Ecological: Relates to differences in breeding periods.
• Ethological: Changes in sexual behavior.

Differential Adaptation

Each group adapts to its environment. Individuals with genetic traits best suited to survive will persist, while others may become extinct.

Paleontology and Fossils

A fossil is the preserved remainder or activity of an organism from a bygone era. Paleontology is the science of fossils, intersecting with geology, ecology, and evolution.

• Processes: Mineralization, freezing, dehydration, inclusion, and trace fossils.

Biodiversity and Vital Functions

Biodiversity is the variety of life existing in the biosphere. Vital functions include nutrition, reproduction, and relationship.

Threats to Biodiversity

Uncontrolled development, construction, overfishing, pollution, industrial activity, forest fires, and the illegal hunting or trade of exotic species.

Microorganisms

Bacteria

Prokaryotic, unicellular organisms with various forms of nutrition, reproducing asexually.

• Types: Cocci, bacilli, spirilla, vibrios.
• Nutrition: Autotrophic (photosynthetic and chemosynthetic) or Heterotrophic (saprophytic, parasitic, or symbiotic).

Protozoa

Unicellular eukaryotic organisms inhabiting aquatic and soil environments. They do not conduct photosynthesis and can live freely or as parasites.

• Classification: Flagella, cilia, pseudopodia, or motionless.

Lichens

Bodies formed by the symbiotic association between a fungus and an alga. They do not belong to either kingdom. Types include crustose, foliose, and fruticose.