¶ Key Understandings:
- Classifying living things into major taxonomic groups enables us to make sense of the biodiversity around us.
- In the natural system of classification, organisms are classified into major taxonomic groups according to a graded scale of hierarchy based on their characteristics
- The diversity of contemporary life reflects past episodes of speciation and evolution
- Biodiversity is important for the continual survival of living things
- Humans have to use the rich resources in nature responsibly and sustainably
- Man continually seeks to understand the complexity in the natural world by studying it in a systematic manner
- A classification system (systematics) allows us to identify and classify individuals into species and refine the evolutionary relationships among organisms
- Recognise that classifying living things into major taxonomic groups (domain, kingdom, phylum, genus and species) enables us to make sense of the biodiversity around us.
- Write proper scientific names for organisms following the Binomial nomenclature.
¶ Recognise that classifying living things into major taxonomic groups (domain, kingdom, phylum, genus and species) enables us to make sense of the biodiversity around us.
- Biodiversity is the range of living organisms present on Earth
- There is a wide variety of organisms on earth (2 - 10 million species are estimated to exist globally)
- Even in Singapore
- We even have endemic species that are found only in Singapore (They are found nowhere else in the world)
- A rich biodiversity is important as:
- Maintains a stable system in nature as all the species in an ecosystem are interdependent
- Provides humans with:
- Resources (source of food & medicine)
- Ecological services (e.g. pollination, clean water)
- Intrinsic value (personal positive feelings)
- Unfortunately, we are now experiencing the sixth mass extinction
- Threats to biodiversity include:
- Human destruction of ecosystems (loss of habitats)
- Over-exploitation of species (hunting) and natural resources
- Human overpopulation
- Pollution
- Alien species invasion
- Human-wildlife conflicts
- Disease
- A classification system allows us to make sense of the biodiversity around us
- It imposes order and a general plan upon the diversity of living things by sorting organisms into groups based on their similarities and differences
- This is important as it allows us to:
- Identify species (to find out which group an unknown organism belongs to by looking at its characteristics)
- Predict how species evolve (as members in the same group share characteristics as they have evolved from a common ancestor)
- Predict what characteristics a species has (as species that are grouped together would probably have the same characteristics)
- Systematics is the scientific study of the diversity of organisms and their evolutionary relationships
- Linnaean Classification System
- Created by Carls Linnaeus
- He organized organisms based on similar and different (usually morphological) characteristics using ranks that reflect structure and function
- The seven major taxonomic ranks from the most general to most specific are:
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
- Phylocode (Cladistics) is another system of classification that is based on the presence or absence of shared derived characters (evolutionary relationships) using clades that reflect descent from one ancestor
¶ Three Domains
- Bacteria
- Archaea
- Protista
- Fungi
- Plantae
- Animalia
- Taxonomy (an aspect of systematics) is the science of naming, describing and classifying organisms
- The binomial nomenclature is part of the rules governing the assignment and application of formal scientific names to organisms or groups of organism that has been internationally agree
- Name consist of two parts:
- Genus + species (both in Latin)
- Genus name always with first letter in upper case
- Specific epithet always in lower case, never in caps
- Species name always italicised (Escherichia coli) or underlined
- Click on this link to view the Flash applet made by Cary & Michael Huang