5.3 Classification of biodiversity Flashcards
(97 cards)
Convention for naming living organisms
Convention for naming living organisms
- The accepted convention of using one common system for the naming of living organisms is an essential basis for scientific research.
- The convention always follows the Genus species (both in italics) format.
Define species
A group of organisms in the same genus that is able to interbreed to produce fertile offspring.
Define genus
A group of species that share common characteristics but may not be able to interbreed.
What is the difference between genus and species?
- A genus is a group of species that share characteristics.
- For example, the -genus Macropus, or ‘big foot’, is a genus of kangaroos that all have big hind legs.
- The species name is specific to that organism and may refer to a specific trait of that particular organism.
- For example, Macropus rufus is a red kangaroo.
What are the rules that scientists follow when it comes to naming a species with these scientific names?
- Genus name starts with a capital (upper case) letter.
- Species name starts with a lowercase letter.
- Genus name is always written before the species name.
- The complete name, i.e. genus and species should be word processed in italics or underlined when handwritten.
- Genus and species names are often written using Latin or classical Greek because they are unchanging languages. However, there are many other sources of binomial names.
Universality of the binomial system of names for species
- The binomial system of names for species is universal (used by all) and has been agreed upon and developed at a series of congresses.
- Each time a new species is discovered, it is given a scientific name using the binomial system.
Abbreviation of genus names
- The genus name is often abbreviated once it has been used in a text.
- So, from this point onwards, we would use M. rufus rather than having to use the complete name, Macropus rufus.
Classification of species into subspecies
- Some species may be classified into subspecies.
- Organisms placed in the same species and subspecies are able to interbreed to have fertile offspring. For example, there are two subspecies of the eastern grey kangaroo ( Macropus giganteus), the Macropus giganteus giganteus and the Macropus giganteus tasmaniensis, also known as the Tasmanian eastern grey kangaroo.
- These two subspecies of kangaroo are able to interbreed to have fertile young. However, they do not often interbreed in nature because they are geographically isolated.
- Macropus giganteus giganteus is endemic in mainland Australia, whereas the Macropus giganteus tasmaniensis is endemic on the island of Tasmania.
- Neither subspecies of the grey kangaroo are able to interbreed with the red kangaroo ( M. rufus ) because it is classified as a different species.
What are organisms that are placedin the same species and subspecies able to do?
Interbreed to have fertile offspring
What are Allium sativum and Allium cepa?
Two different species of the same genus
Both of these organisms are called Allium so they belong to the same genus. They have different species names: sativa and cepa, so they are two different species.
What is the correct way of writing the scientific name of asparagus?
Asparagus officinalis (in italics)
Two kangaroos have the following scientific names respectively: M. giganteus giganteus and M. giganteus tasmaniensis.
What do you know about these two types of kangaroo?
They are two subspecies of the same species.
What does the genus combine?
- Organisms that resemble each other in one or more characteristics.
- For example, the big hind legs in the kangaroo genus Macropus.
What can the genera (plural of genus) be grouped into?
Families
What can families be grouped into?
Orders
Groupings beyond genus
- The genera (plural of genus) can be grouped into families, and families can be grouped into orders.
- Each of the groupings is called a taxon (plural taxa).
- As we go up each level, to the level of a domain, each higher level includes a larger group of organisms.
- In other words, there is a hierarchy of taxa.
The more taxa organisms share, ___
The more they have in common.
When are organisms able to interbreed to produce fertile offspring?
When they share the same taxa down to the species level.
Diagram showing biological classification
What are the principal taxa for classifying eukaryotes?
Kingdom , phylum , class , order , family , genus, and species
What is the highest level of classification?
A domain
How were organisms classified before DNA sequences could be used to classify organisms?
They were divided into prokaryotes (Latin: Prokaryota ) also known as monera, organisms without a nucleus, and eukaryotes (Latin: Eukaryota ), those with a nucleus.
What did Carol Woese discover in 1977 and what did this change?
- In 1977, while using DNA sequencing information to group organisms, an evolutionary microbiologist called Carl Woese discovered that organisms grouped together into prokaryotes actually had two separate ancestors.
- Thus, there are three lines of living things (and not two).