In biology, what would classification refer to?
There are millions and millions of species, so classifying organisms into proper categories can be a difficult task. To make it easier for all scientists to do, a classification system had to be developed.
The evolution of life on Earth over the past 4 billion years has resulted in a huge variety of species. For more than 2,000 years, humans have been trying to classify the great diversity of life. The science of classifying organisms is called taxonomy. Classification is an important step in understanding the present diversity and past evolutionary history of life on Earth.
All modern classification systems have their roots in the Linnaean classification system. It was developed by Swedish botanist Carolus Linnaeus in the 1700s. He tried to classify all living things that were known at his time. He grouped together organisms that shared obvious physical traits, such as number of legs or shape of leaves. For his contribution, Linnaeus is known as the “father of taxonomy.” You can learn more about Linnaeus and his system of classification by watching the video at this link: http://teachertube.com/viewVideo.php?video_id=169889. The Linnaean system of classification consists of a hierarchy of groupings, called taxa (singular, taxon). Taxa range from the kingdom to the species (see Figure below). The kingdom is the largest and most inclusive grouping. It consists of organisms that share just a few basic similarities. Examples are the plant and animal kingdoms. The species is the smallest and most exclusive grouping. It consists of organisms that are similar enough to produce fertile offspring together. Closely related species are grouped together in a genus.
Linnaean Classification System: Classification of the Human Species. This chart shows the taxa of the Linnaean classification system. Each taxon is a subdivision of the taxon below it in the chart. For example, a species is a subdivision of a genus. The classification of humans is given in the chart as an example.
Perhaps the single greatest contribution Linnaeus made to science was his method of naming species. This method, called binomial nomenclature, gives each species a unique, two-word Latin name consisting of the genus name and the species name. An example is Homo sapiens, the two-word Latin name for humans. It literally means “wise human.” This is a reference to our big brains. Why is having two names so important? It is similar to people having a first and a last name. You may know several people with the first name Michael, but adding Michael’s last name usually pins down exactly whom you mean. In the same way, having two names uniquely identifies a species.
Revisions in Linnaean Classification
Linnaeus published his classification system in the 1700s. Since then, many new species have been discovered. The biochemistry of many organisms has also become known. Eventually, scientists realized that Linnaeus’s system of classification needed revision. A major change to the Linnaean system was the addition of a new taxon called the domain. A domain is a taxon that is larger and more inclusive than the kingdom. Most biologists agree there are three domains of life on Earth: Bacteria, Archaea, and Eukaryota (see Figure below). Both Bacteria and Archaea consist of single-celled prokaryotes. Eukaryota consists of all eukaryotes, from single-celled protists to humans. This domain includes the Animalia (animals), Plantae (plants), Fungi (fungi), and Protista (protists) kingdoms.
Three-Domain Classification. This diagram shows the three domains of organisms that currently live on Earth.
Connecting The Pieces
Soft Bodies Aren't All Bad
The Burgess Shale located in Yoho National Park, British Columbia, Canada is considered by many to be the most important fossil bed yet found. This fossil bed is known not only for the complexity and diversity of the organisms preserved but also for the preservation of soft body parts like organs and even whole organ systems. The beds are also over 500 million years old and represent an incredible resource to scientists seeking to understand life during the Cambrian Era and how it compares to life today. Watch the following video to take a look and these incredible fossil beds.
Here you can see someone who has actually worked at the fossil bed talk about the significance of the Burgess Shale and what it was like to work there
Here you can see some of the actual fossils themselves (and a few Japanese models)
Use the below resources to answer the following questions
- What does Lagerstätten mean?
- What physical conditions lead to optimal fossilization?
- What latitude was “North America” located at when the Burgess Shale was deposited?
- How does the preservation of soft body parts increase scientists knowledge of the organism that made the fossils? Explain your answer as fully as possible.
- What kinds of information can scientists get from soft body parts that they cannot get from hard body parts?
- Do all animals have hard body parts?
- How do the organisms in the Burgess Shale compare to organisms in other fossil beds of the same age? Are they the same organisms? Are they different organisms?
- What do we learn when we compare fossil organisms from different fossil beds of the same age to organisms from different areas today?
- http://www.youtube.com/watch?v=jr126K8kDfQ Youtube by BurgessShaleGF
- http://www.youtube.com/watch?v=dCnti9rRL2k Youtube by fossilfactor
- http://www.youtube.com/watch?v=EH9uDMBkR0k Youtube by RoyalOntarioMuseum
- Classification is an important step in understanding life on Earth.
- All modern classification systems have their roots in the Linnaean classification system.
- The Linnaean system is based on similarities in obvious physical traits. It consists of a hierarchy of taxa, from the kingdom to the species.
- Each species is given a unique two-word Latin name.
- The recently added domain is a larger and more inclusive taxon than the kingdom.
Use these resources to answer the questions that follow.
- http://www.hippocampus.org/Biology Biology for AP* Search: Naming Organisms
- Describe the binomial system of nomenclature.
- Distinguish between genus and species.
- Why are species placed into different genera?
- Define taxonomy and describe the role of taxonomists.
- How are bats and humans related?
- http://www.hippocampus.org/Biology Biology for AP* Search: Modern Taxonomy
- Compare early taxonomy to modern taxonomy.
- What is a domain? What are the various domains?
1. What is taxonomy?
2. Define taxon and give an example.
3. What is binomial nomenclature? Why is it important?
4. What is a domain? What are the three domains of life on Earth?
5. Create a taxonomy, modeled on the Linnaean classification system, for a set of common objects, such as motor vehicles, tools, or office supplies. Identify the groupings that correspond to the different taxa in the Linnaean system.