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BIO - 4.2.2 Classification and Evolution > Classification Basics > Flashcards

Flashcards in Classification Basics Deck (6)
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What is classification?

- Classification is the act of arranging organisms into groups based on their similarities and differences.
- This makes it easier for scientists to identify and study them - Taxonomy is the study of classification.
- Until recently the most widely used system contained 7 groups ordered in a hierarchy - these are referred to as taxonomic groups.


Taxonomic groups

- 7 groups are: Kingdom, Phylum, Class, Order, Family, Genus and Species.
- Kingdoms are the biggest and broadest taxonomic group and species is the smallest and most specific classification.
- Related or similar groups at one level are combined into more inclusive groups at the next higher level.



- Based of more studies of genetic material, another level of classification has been added named domain.
- This level is at the top of the hierarchy.
-So similar organisms are first sorted into one of three very large domains.
- Animals, plants and fungi are in the Eukarya domain.
- The 3 domains are Archaea, Bacteria, and Eukarya.


Why do scientists classify organisms?

- To identify species
- To predict characteristics
- To find evolutionary links: species in the same group probably share characteristics as they have evolved from a common ancestor.

Using a single classification system allows scientists worldwide to share their research.



- The smallest units of classification - each group contains only 1 type of organism.
- A species is defines as a group of organisms that are able to reproduce to produce fertile offspring.
- Animals are infertile is they have an odd number of chromosomes as meiosis and gamete production cannot take place correctly.


Binomial system

- To ensure scientists over the world are discussing the same organism, we use a system named binomial nomenclature. This system helps avoid the confusion of common names.

They are given a scientific name consisting of 2 parts:
- First word indicates the genus - it's called the generic name.
- Second word indicates the organism's species - it's called the specific name.
(names are written in italics or underlines; lowercase but genus uppercase)