1. Introduction to Classification Flashcards
(21 cards)
What is classification
- Act of arranging organisms into groups based on their similarities & differences.
- Makes it easier for scientists to identify them & study them.
What is taxonomy
The study of classification.
What do classification systems involve
Placing organisms into groups in a taxonomic hierarchy.
Taxonomic hierarchy
- There are 8 levels of groups (called taxonomic groups) used in classification.
- Similar organisms are first sorted into one of three very large groups called DOMAINS, eg. animals, plants & fungi are in the Eukarya domain.
- Similar organisms are then sorted into slightly smaller groups called KINGDOMS, eg. all animals are in the animal kingdom
- Similar organisms from that kingdom are then grouped into a PHYLUM. Similar organisms from each phylum are then grouped into a CLASS, & so on down the 8 levels of the taxonomic hierarchy.
Acronym for the 8 levels of the taxonomic hierarchy
Dear King Philip Came Over For Good Soup
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
What happens as you move down the taxonomic hierarchy
- There are more groups at each level but fewer organisms in each group.
- Hierarchy ends with SPECIES - the groups that contain only 1 type of organism (Eg, human, dog, E.coli).
5 kingdom classification system
Organisms can be placed into one of 5 kingdoms.
What are the 5 kingdoms
- Prokaryotae
- Protoctista
- Fungi
- Plantae
- Animalia
5 kingdoms: Prokaryotae
EXAMPLE: bacteria
FEATURES: prokaryotic, single-celled, no nucleus, less than 5μm
5 kingdoms: Protocista
EXAMPLES: algae, protozoa
FEATURES: eukaryotic, usually live in water, single-celled or simple multicellular organisms
5 kingdoms: Fungi
EXAMPLES: moulds, yeasts, mushrooms
FEATURES: eukaryotic, chitin cell wall, saprotrophic (absorb substances from dead or decaying organisms), single-celled or multicellular organisms
5 kingdoms: Plantae
EXAMPLES: mosses, ferns, flowering plants
FEATURES: eukaryotic, multicellular, cellulose cell walls, can photosynthesise, contains chlorophyll, autotrophic (produce their own food)
5 kingdoms: Animalia
EXAMPLES: nematodes (roundworms), molluscs, insects, fish, reptiles, birds, mammals
FEATURES: eukaryotic, multicellular, no cell walls, heterotrophic (consume plants & animals)
What are plants also known as
Photoautotrophs - they produce their own food using light
What is the binomial naming system
- The nomenclature (naming system) used for classification is called the binomial system - all organisms are given one internationally accepted scientific name in Latin that has 2 parts.
First & second part of name (binomial naming system)
- First part of name is the genus name & has a capital letter.
- Second part is the species name & begins w a lower case letter.
eg. Homo sapiens for humans
ADVANTAGES of the binomial naming system
- Helps avoid confusion of using common names. eg, over 100 diff plant species are called raspberries.
- Allows scientists to communicate internationally w/o a language barrier.
What is phylogeny
- The study of the evolutionary history of groups of organisms. Tells us abt the evolutionary history of organisms.
- Tells us who’s related to whom & how closely related they are.
How can phylogeny be shown
- All organisms have evolved from shared common ancestors (relatives).
- This can be shown on a phylogenetic tree (eg on pg119 & writing 3.)
Interpretation of a phylogenetic tree
- First branch point represents a common ancestor of all the family members (this ancestor is now extinct).
- Each of following branch points represent another common ancestor from which a different group diverged.
- According to phylogenetic, a species is the smallest group that shares a common ancestor - the end of a branch on a phylogenetic tree - this is known as the phylogenetic species concept.
See pg119 6. and phylogenetic tree for how to interpret relationships
