READING: Taxonomy
Overview
This is a Reading for my Canvas-based BIO100 course.
Module 1
This is a Canvas page associated with content for my BIO100 course.
1.4 READING: Taxonomy
Biology is all about studying life on Earth. There's an amazing variety of living things out there! This diversity comes from a process called evolution, which is when new species develop from older ones over time. Scientists who study evolution look at all kinds of living things, from tiny cells to whole environments.
The branch of Biology that studies the classification of living things is called Taxonomy, which comes from the Ancient Greek words "taxis" (arrangement) and "nomia" (method). Based on this system, living things are grouped according to their similarities into taxa (singular: taxon). Taxa are ranked hierarchically to create smaller taxa within larger taxa. There are dynamic developments within the science of taxonomy, and different branches of biology may use slightly different systems. In this course, we will use the most widely accepted ranking system, which consists of the ranks named:
The hierarchy of biological classification's eight major taxonomic ranks. A Family contains one or more genera. Intermediate minor rankings are not shown.
This image has been released into the public domain by Pengo at English Wikipedia. The artwork is from Peter Halasz.
Modern taxonomy has a much more complex classification system than the one we are learning here. The modern system is still largely based on the work of Carl Linnaeus, who published it in the 18th century but takes into account all the knowledge derived from genetics and the study of DNA.
Before Linnaeus, it was difficult to name and identify organisms because different regions had different names for the same thing. Linnaeus devised a new way to name organisms using two names, called the Binomial Naming System. This system uses a unique name for each organism that includes two parts - the first part is capitalized and represents the Genus, and the second part is all lowercase and represents the Species. For example, the blue jay is known as Cyanocitta cristata, and modern humans are known as Homo sapiens. This system helps scientists from all over the world to identify and refer to the same organism using the same name.
Here is an interesting 13-minute video lecture from Khan Academy (Khan Salman) that looks at the science of Taxonomy and where humans fit into the tree of life: https://www.khanacademy.org/science/biology/her/tree-of-life/v/taxonomy-and-the-tree-of-life
This diagram shows the levels of taxonomic hierarchy for a dog,
from the broadest category—Domain—to the most specific—Species.
What kind of features do biologists look at to decide how to classify a particular form of life? There are many aspects. For example, the general external morphology (i.e., what an organism looks like and how similar it is to another), what special structures are present, what the internal organs look like, how it develops from egg to adult, the structure of their cells, their specific chemistry including the substances their body secretes, and, nowadays, more and more, the code encrypted into their DNA, which determines which proteins the organism can build and how similar those proteins are to another organism.
Other clues include their behaviors, such as special courtship rituals, dances, or calls, and their habits, such as where they live, what food they eat, how they approach the seasons, and what kind of parasites inhabit their bodies.
Attribution: CC BY 4.0 DEED - https://creativecommons.org/licenses/by/4.0/