Classification
- Created by: Laura
- Created on: 10-05-14 10:27
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- Classification
- The concept of a species
- A species is the basic unit of classification. A definition of a species is not easy but members of a single species have certain things in common
- They are similar to one another but different from members of other species - they have very similar genes and therefore closely resemble one another physically and biochemically
- They have similar patterns of development and similar immunological features and they occupy the same ecological niche
- They are capable of breeding to produce living, fertile offspring. They are therefore able successfully to produce more offspring.
- Naming species - the binomial system
- At one time scientists gave new organisms a name that described their features e.g. black bird.
- This resulted in the same name being used in a different part of the world for a completely different species.
- Organisms are identified by two names and hence the system is called the binomial system
- It is a universal system based upon Latin or Greek names
- The first name, called the generic name, denotes the genus to which the organism belongs. This is the equivalent to the surname used to identify people
- The second name, called the specific name, denotes the species to which the organism belongs.
- There are three rules when using this system
- The names are printed in italics or if handwritten they are underlined to show they are scientific names
- The first letter of the generic name is in upper case but the specific name is all in lower case
- If the species name is not known, it can be written as sp.
- At one time scientists gave new organisms a name that described their features e.g. black bird.
- Grouping species together - the principles of classification
- Sort organisms into manageable groups. This allows for better communication between scientists
- This process is known as classification, while the theory and practice of biological classification is called taxonomy
- There are two types of biological classification, each used for a different purpose
- Artificial classification divides organisms according to differences that are useful at the time. Such features may include colour, size, number of legs, leaf shape etc.
- These are described as analogous characteristics where they have the same function but do not have the same function but do not have the same evolutionary origins.
- Natural classification is based upon the evolutionary relationships between organisms and their ancestors, classifies species into groups using shared features derived from their ancestors and they arrange the groups into a hierarchy in which the groups are contained within larger composite groups with no overlap
- Relationships in a natural classification are based upon homologous characteristics. These have similar evolutionary origins regardless of their functions in the adult of the species
- Artificial classification divides organisms according to differences that are useful at the time. Such features may include colour, size, number of legs, leaf shape etc.
- Organising the groups of species - taxonomy
- Each group within a natural biological classification is called a taxon. Taxonomy is the study of these groups and their positions in a hierarchical order, where they are known as taxonomic ranks.
- Kindom
- Phylum
- Class
- Order
- Family
- Genus
- Species
- Genus
- Family
- Order
- Class
- Phylum
- The concept of a species
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